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Posted to commits@ignite.apache.org by is...@apache.org on 2017/11/10 15:07:10 UTC

[1/4] ignite git commit: IGNITE-5218: First version of decision trees. This closes #2936

Repository: ignite
Updated Branches:
  refs/heads/master 6579e69f2 -> db7697b17


http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/util/MnistUtils.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/util/MnistUtils.java b/modules/ml/src/main/java/org/apache/ignite/ml/util/MnistUtils.java
new file mode 100644
index 0000000..03e3198
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/util/MnistUtils.java
@@ -0,0 +1,121 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.util;
+
+import java.io.FileInputStream;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.Random;
+import java.util.stream.Stream;
+import org.apache.ignite.ml.math.impls.vector.DenseLocalOnHeapVector;
+
+/**
+ * Utility class for reading MNIST dataset.
+ */
+public class MnistUtils {
+    /**
+     * Read random {@code count} samples from MNIST dataset from two files (images and labels) into a stream of labeled vectors.
+     * @param imagesPath Path to the file with images.
+     * @param labelsPath Path to the file with labels.
+     * @param rnd Random numbers generatror.
+     * @param count Count of samples to read.
+     * @return Stream of MNIST samples.
+     * @throws IOException
+     */
+    public static Stream<DenseLocalOnHeapVector> mnist(String imagesPath, String labelsPath, Random rnd, int count) throws IOException {
+        FileInputStream isImages = new FileInputStream(imagesPath);
+        FileInputStream isLabels = new FileInputStream(labelsPath);
+
+        int magic = read4Bytes(isImages); // Skip magic number.
+        int numOfImages = read4Bytes(isImages);
+        int imgHeight = read4Bytes(isImages);
+        int imgWidth = read4Bytes(isImages);
+
+        read4Bytes(isLabels); // Skip magic number.
+        read4Bytes(isLabels); // Skip number of labels.
+
+        int numOfPixels = imgHeight * imgWidth;
+
+        System.out.println("Magic: " + magic);
+        System.out.println("Num of images: " + numOfImages);
+        System.out.println("Num of pixels: " + numOfPixels);
+
+        double[][] vecs = new double[numOfImages][numOfPixels + 1];
+
+        for (int imgNum = 0; imgNum < numOfImages; imgNum++) {
+            vecs[imgNum][numOfPixels] = isLabels.read();
+            for (int p = 0; p < numOfPixels; p++) {
+                int c = 128 - isImages.read();
+                vecs[imgNum][p] = (double)c / 128;
+            }
+        }
+
+        List<double[]> lst = Arrays.asList(vecs);
+        Collections.shuffle(lst, rnd);
+
+        isImages.close();
+        isLabels.close();
+
+        return lst.subList(0, count).stream().map(DenseLocalOnHeapVector::new);
+    }
+
+    /**
+     * Convert random {@code count} samples from MNIST dataset from two files (images and labels) into libsvm format.
+     * @param imagesPath Path to the file with images.
+     * @param labelsPath Path to the file with labels.
+     * @param outPath Path to output path.
+     * @param rnd Random numbers generator.
+     * @param count Count of samples to read.
+     * @throws IOException
+     */
+    public static void asLIBSVM(String imagesPath, String labelsPath, String outPath, Random rnd, int count) throws IOException {
+
+        try (FileWriter fos = new FileWriter(outPath)) {
+            mnist(imagesPath, labelsPath, rnd, count).forEach(vec -> {
+                try {
+                    fos.write((int)vec.get(vec.size() - 1) + " ");
+
+                    for (int i = 0; i < vec.size() - 1; i++) {
+                        double val = vec.get(i);
+
+                        if (val != 0)
+                            fos.write((i + 1) + ":" + val + " ");
+                    }
+
+                    fos.write("\n");
+
+                }
+                catch (IOException e) {
+                    e.printStackTrace();
+                }
+            });
+        }
+    }
+
+    /**
+     * Utility method for reading 4 bytes from input stream.
+     * @param is Input stream.
+     * @throws IOException
+     */
+    private static int read4Bytes(FileInputStream is) throws IOException {
+        return (is.read() << 24) | (is.read() << 16) | (is.read() << 8) | (is.read());
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/util/Utils.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/util/Utils.java b/modules/ml/src/main/java/org/apache/ignite/ml/util/Utils.java
new file mode 100644
index 0000000..b7669be
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/util/Utils.java
@@ -0,0 +1,53 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.util;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+
+/**
+ * Class with various utility methods.
+ */
+public class Utils {
+    /**
+     * Perform deep copy of an object.
+     * @param orig Original object.
+     * @param <T> Class of original object;
+     * @return Deep copy of original object.
+     */
+    public static <T> T copy(T orig) {
+        Object obj = null;
+        try {
+            ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            ObjectOutputStream out = new ObjectOutputStream(baos);
+            out.writeObject(orig);
+            out.flush();
+            out.close();
+            ObjectInputStream in = new ObjectInputStream(
+                new ByteArrayInputStream(baos.toByteArray()));
+            obj = in.readObject();
+        }
+        catch (IOException | ClassNotFoundException e) {
+            e.printStackTrace();
+        }
+        return (T)obj;
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/test/java/org/apache/ignite/ml/IgniteMLTestSuite.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/test/java/org/apache/ignite/ml/IgniteMLTestSuite.java b/modules/ml/src/test/java/org/apache/ignite/ml/IgniteMLTestSuite.java
index 5ac7443..47910c8 100644
--- a/modules/ml/src/test/java/org/apache/ignite/ml/IgniteMLTestSuite.java
+++ b/modules/ml/src/test/java/org/apache/ignite/ml/IgniteMLTestSuite.java
@@ -20,6 +20,7 @@ package org.apache.ignite.ml;
 import org.apache.ignite.ml.clustering.ClusteringTestSuite;
 import org.apache.ignite.ml.math.MathImplMainTestSuite;
 import org.apache.ignite.ml.regressions.RegressionsTestSuite;
+import org.apache.ignite.ml.trees.DecisionTreesTestSuite;
 import org.junit.runner.RunWith;
 import org.junit.runners.Suite;
 
@@ -30,7 +31,8 @@ import org.junit.runners.Suite;
 @Suite.SuiteClasses({
     MathImplMainTestSuite.class,
     RegressionsTestSuite.class,
-    ClusteringTestSuite.class
+    ClusteringTestSuite.class,
+    DecisionTreesTestSuite.class
 })
 public class IgniteMLTestSuite {
     // No-op.

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/test/java/org/apache/ignite/ml/TestUtils.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/test/java/org/apache/ignite/ml/TestUtils.java b/modules/ml/src/test/java/org/apache/ignite/ml/TestUtils.java
index 62fdf2c..d094813 100644
--- a/modules/ml/src/test/java/org/apache/ignite/ml/TestUtils.java
+++ b/modules/ml/src/test/java/org/apache/ignite/ml/TestUtils.java
@@ -23,6 +23,8 @@ import org.apache.ignite.ml.math.Precision;
 import org.apache.ignite.ml.math.Vector;
 import org.junit.Assert;
 
+import static org.junit.Assert.assertTrue;
+
 /** */
 public class TestUtils {
     /**
@@ -245,4 +247,17 @@ public class TestUtils {
     public static double maximumAbsoluteRowSum(Matrix mtx) {
         return IntStream.range(0, mtx.rowSize()).mapToObj(mtx::viewRow).map(v -> Math.abs(v.sum())).reduce(Math::max).get();
     }
+
+    /** */
+    public static void checkIsInEpsilonNeighbourhood(Vector[] v1s, Vector[] v2s, double epsilon) {
+        for (int i = 0; i < v1s.length; i++) {
+            assertTrue("Not in epsilon neighbourhood (index " + i + ") ",
+                v1s[i].minus(v2s[i]).kNorm(2) < epsilon);
+        }
+    }
+
+    /** */
+    public static void checkIsInEpsilonNeighbourhood(Vector v1, Vector v2, double epsilon) {
+        checkIsInEpsilonNeighbourhood(new Vector[] {v1}, new Vector[] {v2}, epsilon);
+    }
 }

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/test/java/org/apache/ignite/ml/math/impls/matrix/SparseDistributedBlockMatrixTest.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/test/java/org/apache/ignite/ml/math/impls/matrix/SparseDistributedBlockMatrixTest.java b/modules/ml/src/test/java/org/apache/ignite/ml/math/impls/matrix/SparseDistributedBlockMatrixTest.java
index 2943bc0..fd6ed78 100644
--- a/modules/ml/src/test/java/org/apache/ignite/ml/math/impls/matrix/SparseDistributedBlockMatrixTest.java
+++ b/modules/ml/src/test/java/org/apache/ignite/ml/math/impls/matrix/SparseDistributedBlockMatrixTest.java
@@ -24,6 +24,7 @@ import java.io.ObjectInputStream;
 import java.io.ObjectOutputStream;
 import java.util.Collection;
 import java.util.Set;
+import java.util.UUID;
 import org.apache.ignite.Ignite;
 import org.apache.ignite.IgniteCache;
 import org.apache.ignite.internal.util.IgniteUtils;

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/test/java/org/apache/ignite/ml/trees/BaseDecisionTreeTest.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/test/java/org/apache/ignite/ml/trees/BaseDecisionTreeTest.java b/modules/ml/src/test/java/org/apache/ignite/ml/trees/BaseDecisionTreeTest.java
new file mode 100644
index 0000000..65f0ae4
--- /dev/null
+++ b/modules/ml/src/test/java/org/apache/ignite/ml/trees/BaseDecisionTreeTest.java
@@ -0,0 +1,70 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees;
+
+import java.util.Arrays;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.ml.math.impls.vector.DenseLocalOnHeapVector;
+import org.apache.ignite.ml.structures.LabeledVectorDouble;
+import org.apache.ignite.testframework.junits.common.GridCommonAbstractTest;
+
+/**
+ * Base class for decision trees test.
+ */
+public class BaseDecisionTreeTest extends GridCommonAbstractTest {
+    /** Count of nodes. */
+    private static final int NODE_COUNT = 4;
+
+    /** Grid instance. */
+    protected Ignite ignite;
+
+    /**
+     * Default constructor.
+     */
+    public BaseDecisionTreeTest() {
+        super(false);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override protected void beforeTest() throws Exception {
+        ignite = grid(NODE_COUNT);
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void beforeTestsStarted() throws Exception {
+        for (int i = 1; i <= NODE_COUNT; i++)
+            startGrid(i);
+    }
+
+    /** {@inheritDoc} */
+    @Override protected void afterTestsStopped() throws Exception {
+        stopAllGrids();
+    }
+
+    /**
+     * Convert double array to  {@link LabeledVectorDouble}
+     *
+     * @param arr Array for conversion.
+     * @return LabeledVectorDouble.
+     */
+    protected static LabeledVectorDouble<DenseLocalOnHeapVector> asLabeledVector(double arr[]) {
+        return new LabeledVectorDouble<>(new DenseLocalOnHeapVector(Arrays.copyOf(arr, arr.length - 1)), arr[arr.length - 1]);
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/test/java/org/apache/ignite/ml/trees/ColumnDecisionTreeTrainerTest.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/test/java/org/apache/ignite/ml/trees/ColumnDecisionTreeTrainerTest.java b/modules/ml/src/test/java/org/apache/ignite/ml/trees/ColumnDecisionTreeTrainerTest.java
new file mode 100644
index 0000000..2b03b47
--- /dev/null
+++ b/modules/ml/src/test/java/org/apache/ignite/ml/trees/ColumnDecisionTreeTrainerTest.java
@@ -0,0 +1,190 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.Random;
+import java.util.stream.Collectors;
+import java.util.stream.DoubleStream;
+import org.apache.ignite.internal.util.IgniteUtils;
+import org.apache.ignite.lang.IgniteBiTuple;
+import org.apache.ignite.ml.math.StorageConstants;
+import org.apache.ignite.ml.math.Tracer;
+import org.apache.ignite.ml.math.functions.IgniteFunction;
+import org.apache.ignite.ml.math.impls.matrix.SparseDistributedMatrix;
+import org.apache.ignite.ml.math.impls.vector.DenseLocalOnHeapVector;
+import org.apache.ignite.ml.structures.LabeledVectorDouble;
+import org.apache.ignite.ml.trees.models.DecisionTreeModel;
+import org.apache.ignite.ml.trees.trainers.columnbased.ColumnDecisionTreeTrainer;
+import org.apache.ignite.ml.trees.trainers.columnbased.ColumnDecisionTreeTrainerInput;
+import org.apache.ignite.ml.trees.trainers.columnbased.MatrixColumnDecisionTreeTrainerInput;
+import org.apache.ignite.ml.trees.trainers.columnbased.contsplitcalcs.ContinuousSplitCalculators;
+import org.apache.ignite.ml.trees.trainers.columnbased.regcalcs.RegionCalculators;
+
+/** Tests behaviour of ColumnDecisionTreeTrainer. */
+public class ColumnDecisionTreeTrainerTest extends BaseDecisionTreeTest {
+    /**
+     * Test {@link ColumnDecisionTreeTrainerTest} for mixed (continuous and categorical) data with Gini impurity.
+     */
+    public void testCacheMixedGini() {
+        IgniteUtils.setCurrentIgniteName(ignite.configuration().getIgniteInstanceName());
+        int totalPts = 1 << 10;
+        int featCnt = 2;
+
+        HashMap<Integer, Integer> catsInfo = new HashMap<>();
+        catsInfo.put(1, 3);
+
+        Random rnd = new Random(12349L);
+
+        SplitDataGenerator<DenseLocalOnHeapVector> gen = new SplitDataGenerator<>(
+            featCnt, catsInfo, () -> new DenseLocalOnHeapVector(featCnt + 1), rnd).
+            split(0, 1, new int[] {0, 2}).
+            split(1, 0, -10.0);
+
+        testByGen(totalPts, catsInfo, gen, ContinuousSplitCalculators.GINI.apply(ignite), RegionCalculators.GINI, RegionCalculators.MEAN, rnd);
+    }
+
+    /**
+     * Test {@link ColumnDecisionTreeTrainerTest} for mixed (continuous and categorical) data with Variance impurity.
+     */
+    public void testCacheMixed() {
+        IgniteUtils.setCurrentIgniteName(ignite.configuration().getIgniteInstanceName());
+        int totalPts = 1 << 10;
+        int featCnt = 2;
+
+        HashMap<Integer, Integer> catsInfo = new HashMap<>();
+        catsInfo.put(1, 3);
+
+        Random rnd = new Random(12349L);
+
+        SplitDataGenerator<DenseLocalOnHeapVector> gen = new SplitDataGenerator<>(
+            featCnt, catsInfo, () -> new DenseLocalOnHeapVector(featCnt + 1), rnd).
+            split(0, 1, new int[] {0, 2}).
+            split(1, 0, -10.0);
+
+        testByGen(totalPts, catsInfo, gen, ContinuousSplitCalculators.VARIANCE, RegionCalculators.VARIANCE, RegionCalculators.MEAN, rnd);
+    }
+
+    /**
+     * Test {@link ColumnDecisionTreeTrainerTest} for continuous data with Variance impurity.
+     */
+    public void testCacheCont() {
+        IgniteUtils.setCurrentIgniteName(ignite.configuration().getIgniteInstanceName());
+        int totalPts = 1 << 10;
+        int featCnt = 12;
+
+        HashMap<Integer, Integer> catsInfo = new HashMap<>();
+
+        Random rnd = new Random(12349L);
+
+        SplitDataGenerator<DenseLocalOnHeapVector> gen = new SplitDataGenerator<>(
+            featCnt, catsInfo, () -> new DenseLocalOnHeapVector(featCnt + 1), rnd).
+            split(0, 0, -10.0).
+            split(1, 0, 0.0).
+            split(1, 1, 2.0).
+            split(3, 7, 50.0);
+
+        testByGen(totalPts, catsInfo, gen, ContinuousSplitCalculators.VARIANCE, RegionCalculators.VARIANCE, RegionCalculators.MEAN, rnd);
+    }
+
+    /**
+     * Test {@link ColumnDecisionTreeTrainerTest} for continuous data with Gini impurity.
+     */
+    public void testCacheContGini() {
+        IgniteUtils.setCurrentIgniteName(ignite.configuration().getIgniteInstanceName());
+        int totalPts = 1 << 10;
+        int featCnt = 12;
+
+        HashMap<Integer, Integer> catsInfo = new HashMap<>();
+
+        Random rnd = new Random(12349L);
+
+        SplitDataGenerator<DenseLocalOnHeapVector> gen = new SplitDataGenerator<>(
+            featCnt, catsInfo, () -> new DenseLocalOnHeapVector(featCnt + 1), rnd).
+            split(0, 0, -10.0).
+            split(1, 0, 0.0).
+            split(1, 1, 2.0).
+            split(3, 7, 50.0);
+
+        testByGen(totalPts, catsInfo, gen, ContinuousSplitCalculators.GINI.apply(ignite), RegionCalculators.GINI, RegionCalculators.MEAN, rnd);
+    }
+
+    /**
+     * Test {@link ColumnDecisionTreeTrainerTest} for categorical data with Variance impurity.
+     */
+    public void testCacheCat() {
+        IgniteUtils.setCurrentIgniteName(ignite.configuration().getIgniteInstanceName());
+        int totalPts = 1 << 10;
+        int featCnt = 12;
+
+        HashMap<Integer, Integer> catsInfo = new HashMap<>();
+        catsInfo.put(5, 7);
+
+        Random rnd = new Random(12349L);
+
+        SplitDataGenerator<DenseLocalOnHeapVector> gen = new SplitDataGenerator<>(
+            featCnt, catsInfo, () -> new DenseLocalOnHeapVector(featCnt + 1), rnd).
+            split(0, 5, new int[] {0, 2, 5});
+
+        testByGen(totalPts, catsInfo, gen, ContinuousSplitCalculators.VARIANCE, RegionCalculators.VARIANCE, RegionCalculators.MEAN, rnd);
+    }
+
+    /** */
+    private <D extends ContinuousRegionInfo> void testByGen(int totalPts, HashMap<Integer, Integer> catsInfo,
+        SplitDataGenerator<DenseLocalOnHeapVector> gen,
+        IgniteFunction<ColumnDecisionTreeTrainerInput, ? extends ContinuousSplitCalculator<D>> calc,
+        IgniteFunction<ColumnDecisionTreeTrainerInput, IgniteFunction<DoubleStream, Double>> catImpCalc,
+        IgniteFunction<DoubleStream, Double> regCalc, Random rnd) {
+
+        List<IgniteBiTuple<Integer, DenseLocalOnHeapVector>> lst = gen.
+            points(totalPts, (i, rn) -> i).
+            collect(Collectors.toList());
+
+        int featCnt = gen.featuresCnt();
+
+        Collections.shuffle(lst, rnd);
+
+        SparseDistributedMatrix m = new SparseDistributedMatrix(totalPts, featCnt + 1, StorageConstants.COLUMN_STORAGE_MODE, StorageConstants.RANDOM_ACCESS_MODE);
+
+        Map<Integer, List<LabeledVectorDouble>> byRegion = new HashMap<>();
+
+        int i = 0;
+        for (IgniteBiTuple<Integer, DenseLocalOnHeapVector> bt : lst) {
+            byRegion.putIfAbsent(bt.get1(), new LinkedList<>());
+            byRegion.get(bt.get1()).add(asLabeledVector(bt.get2().getStorage().data()));
+            m.setRow(i, bt.get2().getStorage().data());
+            i++;
+        }
+
+        ColumnDecisionTreeTrainer<D> trainer =
+            new ColumnDecisionTreeTrainer<>(3, calc, catImpCalc, regCalc, ignite);
+
+        DecisionTreeModel mdl = trainer.train(new MatrixColumnDecisionTreeTrainerInput(m, catsInfo));
+
+        byRegion.keySet().forEach(k -> {
+            LabeledVectorDouble sp = byRegion.get(k).get(0);
+            Tracer.showAscii(sp.vector());
+            System.out.println("Act: " + sp.label() + " " + " pred: " + mdl.predict(sp.vector()));
+            assert mdl.predict(sp.vector()) == sp.doubleLabel();
+        });
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/test/java/org/apache/ignite/ml/trees/DecisionTreesTestSuite.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/test/java/org/apache/ignite/ml/trees/DecisionTreesTestSuite.java b/modules/ml/src/test/java/org/apache/ignite/ml/trees/DecisionTreesTestSuite.java
new file mode 100644
index 0000000..3343503
--- /dev/null
+++ b/modules/ml/src/test/java/org/apache/ignite/ml/trees/DecisionTreesTestSuite.java
@@ -0,0 +1,33 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees;
+
+import org.junit.runner.RunWith;
+import org.junit.runners.Suite;
+
+/**
+ * Test suite for all tests located in org.apache.ignite.ml.trees package
+ */
+@RunWith(Suite.class)
+@Suite.SuiteClasses({
+    ColumnDecisionTreeTrainerTest.class,
+    GiniSplitCalculatorTest.class,
+    VarianceSplitCalculatorTest.class
+})
+public class DecisionTreesTestSuite {
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/test/java/org/apache/ignite/ml/trees/GiniSplitCalculatorTest.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/test/java/org/apache/ignite/ml/trees/GiniSplitCalculatorTest.java b/modules/ml/src/test/java/org/apache/ignite/ml/trees/GiniSplitCalculatorTest.java
new file mode 100644
index 0000000..c92b4f5
--- /dev/null
+++ b/modules/ml/src/test/java/org/apache/ignite/ml/trees/GiniSplitCalculatorTest.java
@@ -0,0 +1,141 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees;
+
+import java.util.stream.DoubleStream;
+import org.apache.ignite.ml.trees.trainers.columnbased.contsplitcalcs.GiniSplitCalculator;
+import org.apache.ignite.ml.trees.trainers.columnbased.vectors.SplitInfo;
+import org.junit.Test;
+
+/**
+ * Test of {@link GiniSplitCalculator}.
+ */
+public class GiniSplitCalculatorTest {
+    /** Test calculation of region info consisting from one point. */
+    @Test
+    public void testCalculateRegionInfoSimple() {
+        double labels[] = new double[] {0.0};
+
+        assert new GiniSplitCalculator(labels).calculateRegionInfo(DoubleStream.of(labels), 0).impurity() == 0.0;
+    }
+
+    /** Test calculation of region info consisting from two distinct classes. */
+    @Test
+    public void testCalculateRegionInfoTwoClasses() {
+        double labels[] = new double[] {0.0, 1.0};
+
+        assert new GiniSplitCalculator(labels).calculateRegionInfo(DoubleStream.of(labels), 0).impurity() == 0.5;
+    }
+
+    /** Test calculation of region info consisting from three distinct classes. */
+    @Test
+    public void testCalculateRegionInfoThreeClasses() {
+        double labels[] = new double[] {0.0, 1.0, 2.0};
+
+        assert Math.abs(new GiniSplitCalculator(labels).calculateRegionInfo(DoubleStream.of(labels), 0).impurity() - 2.0 / 3) < 1E-5;
+    }
+
+    /** Test calculation of split of region consisting from one point. */
+    @Test
+    public void testSplitSimple() {
+        double labels[] = new double[] {0.0};
+        double values[] = new double[] {0.0};
+        Integer[] samples = new Integer[] {0};
+
+        int cnts[] = new int[] {1};
+
+        GiniSplitCalculator.GiniData data = new GiniSplitCalculator.GiniData(0.0, 1, cnts, 1);
+
+        assert new GiniSplitCalculator(labels).splitRegion(samples, values, labels, 0, data) == null;
+    }
+
+    /** Test calculation of split of region consisting from two points. */
+    @Test
+    public void testSplitTwoClassesTwoPoints() {
+        double labels[] = new double[] {0.0, 1.0};
+        double values[] = new double[] {0.0, 1.0};
+        Integer[] samples = new Integer[] {0, 1};
+
+        int cnts[] = new int[] {1, 1};
+
+        GiniSplitCalculator.GiniData data = new GiniSplitCalculator.GiniData(0.5, 2, cnts, 1.0 * 1.0 + 1.0 * 1.0);
+
+        SplitInfo<GiniSplitCalculator.GiniData> split = new GiniSplitCalculator(labels).splitRegion(samples, values, labels, 0, data);
+
+        assert split.leftData().impurity() == 0;
+        assert split.leftData().counts()[0] == 1;
+        assert split.leftData().counts()[1] == 0;
+        assert split.leftData().getSize() == 1;
+
+        assert split.rightData().impurity() == 0;
+        assert split.rightData().counts()[0] == 0;
+        assert split.rightData().counts()[1] == 1;
+        assert split.rightData().getSize() == 1;
+    }
+
+    /** Test calculation of split of region consisting from four distinct values. */
+    @Test
+    public void testSplitTwoClassesFourPoints() {
+        double labels[] = new double[] {0.0, 0.0, 1.0, 1.0};
+        double values[] = new double[] {0.0, 1.0, 2.0, 3.0};
+
+        Integer[] samples = new Integer[] {0, 1, 2, 3};
+
+        int[] cnts = new int[] {2, 2};
+
+        GiniSplitCalculator.GiniData data = new GiniSplitCalculator.GiniData(0.5, 4, cnts, 2.0 * 2.0 + 2.0 * 2.0);
+
+        SplitInfo<GiniSplitCalculator.GiniData> split = new GiniSplitCalculator(labels).splitRegion(samples, values, labels, 0, data);
+
+        assert split.leftData().impurity() == 0;
+        assert split.leftData().counts()[0] == 2;
+        assert split.leftData().counts()[1] == 0;
+        assert split.leftData().getSize() == 2;
+
+        assert split.rightData().impurity() == 0;
+        assert split.rightData().counts()[0] == 0;
+        assert split.rightData().counts()[1] == 2;
+        assert split.rightData().getSize() == 2;
+    }
+
+    /** Test calculation of split of region consisting from three distinct values. */
+    @Test
+    public void testSplitThreePoints() {
+        double labels[] = new double[] {0.0, 1.0, 2.0};
+        double values[] = new double[] {0.0, 1.0, 2.0};
+        Integer[] samples = new Integer[] {0, 1, 2};
+
+        int[] cnts = new int[] {1, 1, 1};
+
+        GiniSplitCalculator.GiniData data = new GiniSplitCalculator.GiniData(2.0 / 3, 3, cnts, 1.0 * 1.0 + 1.0 * 1.0 + 1.0 * 1.0);
+
+        SplitInfo<GiniSplitCalculator.GiniData> split = new GiniSplitCalculator(labels).splitRegion(samples, values, labels, 0, data);
+
+        assert split.leftData().impurity() == 0.0;
+        assert split.leftData().counts()[0] == 1;
+        assert split.leftData().counts()[1] == 0;
+        assert split.leftData().counts()[2] == 0;
+        assert split.leftData().getSize() == 1;
+
+        assert split.rightData().impurity() == 0.5;
+        assert split.rightData().counts()[0] == 0;
+        assert split.rightData().counts()[1] == 1;
+        assert split.rightData().counts()[2] == 1;
+        assert split.rightData().getSize() == 2;
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/test/java/org/apache/ignite/ml/trees/SplitDataGenerator.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/test/java/org/apache/ignite/ml/trees/SplitDataGenerator.java b/modules/ml/src/test/java/org/apache/ignite/ml/trees/SplitDataGenerator.java
new file mode 100644
index 0000000..279e685
--- /dev/null
+++ b/modules/ml/src/test/java/org/apache/ignite/ml/trees/SplitDataGenerator.java
@@ -0,0 +1,390 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.ignite.ml.trees;
+
+import java.io.Serializable;
+import java.util.Arrays;
+import java.util.BitSet;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.Random;
+import java.util.function.BiFunction;
+import java.util.function.Function;
+import java.util.function.Supplier;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+import org.apache.ignite.lang.IgniteBiTuple;
+import org.apache.ignite.ml.math.Vector;
+import org.apache.ignite.ml.math.exceptions.MathIllegalArgumentException;
+import org.apache.ignite.ml.util.Utils;
+
+/**
+ * Utility class for generating data which has binary tree split structure.
+ *
+ * @param <V>
+ */
+public class SplitDataGenerator<V extends Vector> {
+    /** */
+    private static final double DELTA = 100.0;
+
+    /** Map of the form of (is categorical -> list of region indexes). */
+    private final Map<Boolean, List<Integer>> di;
+
+    /** List of regions. */
+    private final List<Region> regs;
+
+    /** Data of bounds of regions. */
+    private final Map<Integer, IgniteBiTuple<Double, Double>> boundsData;
+
+    /** Random numbers generator. */
+    private final Random rnd;
+
+    /** Supplier of vectors. */
+    private final Supplier<V> supplier;
+
+    /** Features count. */
+    private final int featCnt;
+
+    /**
+     * Create SplitDataGenerator.
+     *
+     * @param featCnt Features count.
+     * @param catFeaturesInfo Information about categorical features in form of map (feature index -> categories
+     * count).
+     * @param supplier Supplier of vectors.
+     * @param rnd Random numbers generator.
+     */
+    public SplitDataGenerator(int featCnt, Map<Integer, Integer> catFeaturesInfo, Supplier<V> supplier, Random rnd) {
+        regs = new LinkedList<>();
+        boundsData = new HashMap<>();
+        this.rnd = rnd;
+        this.supplier = supplier;
+        this.featCnt = featCnt;
+
+        // Divide indexes into indexes of categorical coordinates and indexes of continuous coordinates.
+        di = IntStream.range(0, featCnt).
+            boxed().
+            collect(Collectors.partitioningBy(catFeaturesInfo::containsKey));
+
+        // Categorical coordinates info.
+        Map<Integer, CatCoordInfo> catCoords = new HashMap<>();
+        di.get(true).forEach(i -> {
+            BitSet bs = new BitSet();
+            bs.set(0, catFeaturesInfo.get(i));
+            catCoords.put(i, new CatCoordInfo(bs));
+        });
+
+        // Continuous coordinates info.
+        Map<Integer, ContCoordInfo> contCoords = new HashMap<>();
+        di.get(false).forEach(i -> {
+            contCoords.put(i, new ContCoordInfo());
+            boundsData.put(i, new IgniteBiTuple<>(-1.0, 1.0));
+        });
+
+        Region firstReg = new Region(catCoords, contCoords, 0);
+        regs.add(firstReg);
+    }
+
+    /**
+     * Categorical coordinate info.
+     */
+    private static class CatCoordInfo implements Serializable {
+        /**
+         * Defines categories which are included in this region
+         */
+        private final BitSet bs;
+
+        /**
+         * Construct CatCoordInfo.
+         *
+         * @param bs Bitset.
+         */
+        CatCoordInfo(BitSet bs) {
+            this.bs = bs;
+        }
+
+        /** {@inheritDoc} */
+        @Override public String toString() {
+            return "CatCoordInfo [" +
+                "bs=" + bs +
+                ']';
+        }
+    }
+
+    /**
+     * Continuous coordinate info.
+     */
+    private static class ContCoordInfo implements Serializable {
+        /**
+         * Left (min) bound of region.
+         */
+        private double left;
+
+        /**
+         * Right (max) bound of region.
+         */
+        private double right;
+
+        /**
+         * Construct ContCoordInfo.
+         */
+        ContCoordInfo() {
+            left = Double.NEGATIVE_INFINITY;
+            right = Double.POSITIVE_INFINITY;
+        }
+
+        /** {@inheritDoc} */
+        @Override public String toString() {
+            return "ContCoordInfo [" +
+                "left=" + left +
+                ", right=" + right +
+                ']';
+        }
+    }
+
+    /**
+     * Class representing information about region.
+     */
+    private static class Region implements Serializable {
+        /**
+         * Information about categorical coordinates restrictions of this region in form of
+         * (coordinate index -> restriction)
+         */
+        private final Map<Integer, CatCoordInfo> catCoords;
+
+        /**
+         * Information about continuous coordinates restrictions of this region in form of
+         * (coordinate index -> restriction)
+         */
+        private final Map<Integer, ContCoordInfo> contCoords;
+
+        /**
+         * Region should contain {@code 1/2^twoPow * totalPoints} points.
+         */
+        private int twoPow;
+
+        /**
+         * Construct region by information about restrictions on coordinates (features) values.
+         *
+         * @param catCoords Restrictions on categorical coordinates.
+         * @param contCoords Restrictions on continuous coordinates
+         * @param twoPow Region should contain {@code 1/2^twoPow * totalPoints} points.
+         */
+        Region(Map<Integer, CatCoordInfo> catCoords, Map<Integer, ContCoordInfo> contCoords, int twoPow) {
+            this.catCoords = catCoords;
+            this.contCoords = contCoords;
+            this.twoPow = twoPow;
+        }
+
+        /** */
+        int divideBy() {
+            return 1 << twoPow;
+        }
+
+        /** */
+        void incTwoPow() {
+            twoPow++;
+        }
+
+        /** {@inheritDoc} */
+        @Override public String toString() {
+            return "Region [" +
+                "catCoords=" + catCoords +
+                ", contCoords=" + contCoords +
+                ", twoPow=" + twoPow +
+                ']';
+        }
+
+        /**
+         * Generate continuous coordinate for this region.
+         *
+         * @param coordIdx Coordinate index.
+         * @param boundsData Data with bounds
+         * @param rnd Random numbers generator.
+         * @return Categorical coordinate value.
+         */
+        double generateContCoord(int coordIdx, Map<Integer, IgniteBiTuple<Double, Double>> boundsData,
+            Random rnd) {
+            ContCoordInfo cci = contCoords.get(coordIdx);
+            double left = cci.left;
+            double right = cci.right;
+
+            if (left == Double.NEGATIVE_INFINITY)
+                left = boundsData.get(coordIdx).get1() - DELTA;
+
+            if (right == Double.POSITIVE_INFINITY)
+                right = boundsData.get(coordIdx).get2() + DELTA;
+
+            double size = right - left;
+
+            return left + rnd.nextDouble() * size;
+        }
+
+        /**
+         * Generate categorical coordinate value for this region.
+         *
+         * @param coordIdx Coordinate index.
+         * @param rnd Random numbers generator.
+         * @return Categorical coordinate value.
+         */
+        double generateCatCoord(int coordIdx, Random rnd) {
+            // Pick random bit.
+            BitSet bs = catCoords.get(coordIdx).bs;
+            int j = rnd.nextInt(bs.length());
+
+            int i = 0;
+            int bn = 0;
+            int bnp = 0;
+
+            while ((bn = bs.nextSetBit(bn)) != -1 && i <= j) {
+                i++;
+                bnp = bn;
+                bn++;
+            }
+
+            return bnp;
+        }
+
+        /**
+         * Generate points for this region.
+         *
+         * @param ptsCnt Count of points to generate.
+         * @param val Label for all points in this region.
+         * @param boundsData Data about bounds of continuous coordinates.
+         * @param catCont Data about which categories can be in this region in the form (coordinate index -> list of
+         * categories indexes).
+         * @param s Vectors supplier.
+         * @param rnd Random numbers generator.
+         * @param <V> Type of vectors.
+         * @return Stream of generated points for this region.
+         */
+        <V extends Vector> Stream<V> generatePoints(int ptsCnt, double val,
+            Map<Integer, IgniteBiTuple<Double, Double>> boundsData, Map<Boolean, List<Integer>> catCont,
+            Supplier<V> s,
+            Random rnd) {
+            return IntStream.range(0, ptsCnt / divideBy()).mapToObj(i -> {
+                V v = s.get();
+                int coordsCnt = v.size();
+                catCont.get(false).forEach(ci -> v.setX(ci, generateContCoord(ci, boundsData, rnd)));
+                catCont.get(true).forEach(ci -> v.setX(ci, generateCatCoord(ci, rnd)));
+
+                v.setX(coordsCnt - 1, val);
+                return v;
+            });
+        }
+    }
+
+    /**
+     * Split region by continuous coordinate.using given threshold.
+     *
+     * @param regIdx Region index.
+     * @param coordIdx Coordinate index.
+     * @param threshold Threshold.
+     * @return {@code this}.
+     */
+    public SplitDataGenerator<V> split(int regIdx, int coordIdx, double threshold) {
+        Region regToSplit = regs.get(regIdx);
+        ContCoordInfo cci = regToSplit.contCoords.get(coordIdx);
+
+        double left = cci.left;
+        double right = cci.right;
+
+        if (threshold < left || threshold > right)
+            throw new MathIllegalArgumentException("Threshold is out of region bounds.");
+
+        regToSplit.incTwoPow();
+
+        Region newReg = Utils.copy(regToSplit);
+        newReg.contCoords.get(coordIdx).left = threshold;
+
+        regs.add(regIdx + 1, newReg);
+        cci.right = threshold;
+
+        IgniteBiTuple<Double, Double> bounds = boundsData.get(coordIdx);
+        double min = bounds.get1();
+        double max = bounds.get2();
+        boundsData.put(coordIdx, new IgniteBiTuple<>(Math.min(threshold, min), Math.max(max, threshold)));
+
+        return this;
+    }
+
+    /**
+     * Split region by categorical coordinate.
+     *
+     * @param regIdx Region index.
+     * @param coordIdx Coordinate index.
+     * @param cats Categories allowed for the left sub region.
+     * @return {@code this}.
+     */
+    public SplitDataGenerator<V> split(int regIdx, int coordIdx, int[] cats) {
+        BitSet subset = new BitSet();
+        Arrays.stream(cats).forEach(subset::set);
+        Region regToSplit = regs.get(regIdx);
+        CatCoordInfo cci = regToSplit.catCoords.get(coordIdx);
+
+        BitSet ssc = (BitSet)subset.clone();
+        BitSet set = cci.bs;
+        ssc.and(set);
+        if (ssc.length() != subset.length())
+            throw new MathIllegalArgumentException("Splitter set is not a subset of a parent subset.");
+
+        ssc.xor(set);
+        set.and(subset);
+
+        regToSplit.incTwoPow();
+        Region newReg = Utils.copy(regToSplit);
+        newReg.catCoords.put(coordIdx, new CatCoordInfo(ssc));
+
+        regs.add(regIdx + 1, newReg);
+
+        return this;
+    }
+
+    /**
+     * Get stream of points generated by this generator.
+     *
+     * @param ptsCnt Points count.
+     */
+    public Stream<IgniteBiTuple<Integer, V>> points(int ptsCnt, BiFunction<Double, Random, Double> f) {
+        regs.forEach(System.out::println);
+
+        return IntStream.range(0, regs.size()).
+            boxed().
+            map(i -> regs.get(i).generatePoints(ptsCnt, f.apply((double)i, rnd), boundsData, di, supplier, rnd).map(v -> new IgniteBiTuple<>(i, v))).flatMap(Function.identity());
+    }
+
+    /**
+     * Count of regions.
+     *
+     * @return Count of regions.
+     */
+    public int regsCount() {
+        return regs.size();
+    }
+
+    /**
+     * Get features count.
+     *
+     * @return Features count.
+     */
+    public int featuresCnt() {
+        return featCnt;
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/test/java/org/apache/ignite/ml/trees/VarianceSplitCalculatorTest.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/test/java/org/apache/ignite/ml/trees/VarianceSplitCalculatorTest.java b/modules/ml/src/test/java/org/apache/ignite/ml/trees/VarianceSplitCalculatorTest.java
new file mode 100644
index 0000000..d67cbc6
--- /dev/null
+++ b/modules/ml/src/test/java/org/apache/ignite/ml/trees/VarianceSplitCalculatorTest.java
@@ -0,0 +1,84 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees;
+
+import java.util.stream.DoubleStream;
+import org.apache.ignite.ml.trees.trainers.columnbased.contsplitcalcs.VarianceSplitCalculator;
+import org.apache.ignite.ml.trees.trainers.columnbased.vectors.SplitInfo;
+import org.junit.Test;
+
+/**
+ * Test for {@link VarianceSplitCalculator}.
+ */
+public class VarianceSplitCalculatorTest {
+    /** Test calculation of region info consisting from one point. */
+    @Test
+    public void testCalculateRegionInfoSimple() {
+        double labels[] = new double[] {0.0};
+
+        assert new VarianceSplitCalculator().calculateRegionInfo(DoubleStream.of(labels), 1).impurity() == 0.0;
+    }
+
+    /** Test calculation of region info consisting from two classes. */
+    @Test
+    public void testCalculateRegionInfoTwoClasses() {
+        double labels[] = new double[] {0.0, 1.0};
+
+        assert new VarianceSplitCalculator().calculateRegionInfo(DoubleStream.of(labels), 2).impurity() == 0.25;
+    }
+
+    /** Test calculation of region info consisting from three classes. */
+    @Test
+    public void testCalculateRegionInfoThreeClasses() {
+        double labels[] = new double[] {1.0, 2.0, 3.0};
+
+        assert Math.abs(new VarianceSplitCalculator().calculateRegionInfo(DoubleStream.of(labels), 3).impurity() - 2.0 / 3) < 1E-10;
+    }
+
+    /** Test calculation of split of region consisting from one point. */
+    @Test
+    public void testSplitSimple() {
+        double labels[] = new double[] {0.0};
+        double values[] = new double[] {0.0};
+        Integer[] samples = new Integer[] {0};
+
+        VarianceSplitCalculator.VarianceData data = new VarianceSplitCalculator.VarianceData(0.0, 1, 0.0);
+
+        assert new VarianceSplitCalculator().splitRegion(samples, values, labels, 0, data) == null;
+    }
+
+    /** Test calculation of split of region consisting from two classes. */
+    @Test
+    public void testSplitTwoClassesTwoPoints() {
+        double labels[] = new double[] {0.0, 1.0};
+        double values[] = new double[] {0.0, 1.0};
+        Integer[] samples = new Integer[] {0, 1};
+
+        VarianceSplitCalculator.VarianceData data = new VarianceSplitCalculator.VarianceData(0.25, 2, 0.5);
+
+        SplitInfo<VarianceSplitCalculator.VarianceData> split = new VarianceSplitCalculator().splitRegion(samples, values, labels, 0, data);
+
+        assert split.leftData().impurity() == 0;
+        assert split.leftData().mean() == 0;
+        assert split.leftData().getSize() == 1;
+
+        assert split.rightData().impurity() == 0;
+        assert split.rightData().mean() == 1;
+        assert split.rightData().getSize() == 1;
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/test/java/org/apache/ignite/ml/trees/performance/ColumnDecisionTreeTrainerBenchmark.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/test/java/org/apache/ignite/ml/trees/performance/ColumnDecisionTreeTrainerBenchmark.java b/modules/ml/src/test/java/org/apache/ignite/ml/trees/performance/ColumnDecisionTreeTrainerBenchmark.java
new file mode 100644
index 0000000..4e7cc24
--- /dev/null
+++ b/modules/ml/src/test/java/org/apache/ignite/ml/trees/performance/ColumnDecisionTreeTrainerBenchmark.java
@@ -0,0 +1,455 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.performance;
+
+import it.unimi.dsi.fastutil.ints.Int2DoubleOpenHashMap;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.Properties;
+import java.util.Random;
+import java.util.UUID;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import java.util.stream.DoubleStream;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.IgniteDataStreamer;
+import org.apache.ignite.Ignition;
+import org.apache.ignite.cache.CacheAtomicityMode;
+import org.apache.ignite.cache.CacheMode;
+import org.apache.ignite.cache.CacheWriteSynchronizationMode;
+import org.apache.ignite.configuration.CacheConfiguration;
+import org.apache.ignite.configuration.IgniteConfiguration;
+import org.apache.ignite.internal.processors.cache.GridCacheProcessor;
+import org.apache.ignite.internal.util.IgniteUtils;
+import org.apache.ignite.lang.IgniteBiTuple;
+import org.apache.ignite.ml.Model;
+import org.apache.ignite.ml.estimators.Estimators;
+import org.apache.ignite.ml.math.StorageConstants;
+import org.apache.ignite.ml.math.Tracer;
+import org.apache.ignite.ml.math.Vector;
+import org.apache.ignite.ml.math.distributed.keys.impl.SparseMatrixKey;
+import org.apache.ignite.ml.math.functions.IgniteFunction;
+import org.apache.ignite.ml.math.functions.IgniteTriFunction;
+import org.apache.ignite.ml.math.impls.matrix.SparseDistributedMatrix;
+import org.apache.ignite.ml.math.impls.storage.matrix.SparseDistributedMatrixStorage;
+import org.apache.ignite.ml.math.impls.vector.DenseLocalOnHeapVector;
+import org.apache.ignite.ml.structures.LabeledVectorDouble;
+import org.apache.ignite.ml.trees.BaseDecisionTreeTest;
+import org.apache.ignite.ml.trees.SplitDataGenerator;
+import org.apache.ignite.ml.trees.models.DecisionTreeModel;
+import org.apache.ignite.ml.trees.trainers.columnbased.BiIndex;
+import org.apache.ignite.ml.trees.trainers.columnbased.BiIndexedCacheColumnDecisionTreeTrainerInput;
+import org.apache.ignite.ml.trees.trainers.columnbased.ColumnDecisionTreeTrainer;
+import org.apache.ignite.ml.trees.trainers.columnbased.MatrixColumnDecisionTreeTrainerInput;
+import org.apache.ignite.ml.trees.trainers.columnbased.caches.ContextCache;
+import org.apache.ignite.ml.trees.trainers.columnbased.caches.FeaturesCache;
+import org.apache.ignite.ml.trees.trainers.columnbased.caches.ProjectionsCache;
+import org.apache.ignite.ml.trees.trainers.columnbased.caches.SplitCache;
+import org.apache.ignite.ml.trees.trainers.columnbased.contsplitcalcs.ContinuousSplitCalculators;
+import org.apache.ignite.ml.trees.trainers.columnbased.contsplitcalcs.GiniSplitCalculator;
+import org.apache.ignite.ml.trees.trainers.columnbased.contsplitcalcs.VarianceSplitCalculator;
+import org.apache.ignite.ml.trees.trainers.columnbased.regcalcs.RegionCalculators;
+import org.apache.ignite.ml.util.MnistUtils;
+import org.apache.ignite.stream.StreamTransformer;
+import org.apache.ignite.testframework.junits.IgniteTestResources;
+import org.apache.log4j.Level;
+import org.junit.Assert;
+
+/**
+ * Various benchmarks for hand runs.
+ */
+public class ColumnDecisionTreeTrainerBenchmark extends BaseDecisionTreeTest {
+    /** Name of the property specifying path to training set images. */
+    private static final String PROP_TRAINING_IMAGES = "mnist.training.images";
+
+    /** Name of property specifying path to training set labels. */
+    private static final String PROP_TRAINING_LABELS = "mnist.training.labels";
+
+    /** Name of property specifying path to test set images. */
+    private static final String PROP_TEST_IMAGES = "mnist.test.images";
+
+    /** Name of property specifying path to test set labels. */
+    private static final String PROP_TEST_LABELS = "mnist.test.labels";
+
+    /** Function to approximate. */
+    private static final Function<Vector, Double> f1 = v -> v.get(0) * v.get(0) + 2 * Math.sin(v.get(1)) + v.get(2);
+
+    /** {@inheritDoc} */
+    @Override protected long getTestTimeout() {
+        return 6000000;
+    }
+
+    /** {@inheritDoc} */
+    @Override protected IgniteConfiguration getConfiguration(String igniteInstanceName,
+        IgniteTestResources rsrcs) throws Exception {
+        IgniteConfiguration configuration = super.getConfiguration(igniteInstanceName, rsrcs);
+        // We do not need any extra event types.
+        configuration.setIncludeEventTypes();
+        configuration.setPeerClassLoadingEnabled(false);
+
+        resetLog4j(Level.INFO, false, GridCacheProcessor.class.getPackage().getName());
+
+        return configuration;
+    }
+
+    /**
+     * This test is for manual run only.
+     * To run this test rename this method so it starts from 'test'.
+     */
+    public void tstCacheMixed() {
+        IgniteUtils.setCurrentIgniteName(ignite.configuration().getIgniteInstanceName());
+        int ptsPerReg = 150;
+        int featCnt = 10;
+
+        HashMap<Integer, Integer> catsInfo = new HashMap<>();
+        catsInfo.put(1, 3);
+
+        Random rnd = new Random(12349L);
+
+        SplitDataGenerator<DenseLocalOnHeapVector> gen = new SplitDataGenerator<>(
+            featCnt, catsInfo, () -> new DenseLocalOnHeapVector(featCnt + 1), rnd).
+            split(0, 1, new int[] {0, 2}).
+            split(1, 0, -10.0).
+            split(0, 0, 0.0);
+
+        testByGenStreamerLoad(ptsPerReg, catsInfo, gen, rnd);
+    }
+
+    /**
+     * Run decision tree classifier on MNIST using bi-indexed cache as a storage for dataset.
+     * To run this test rename this method so it starts from 'test'.
+     *
+     * @throws IOException In case of loading MNIST dataset errors.
+     */
+    public void tstMNISTBiIndexedCache() throws IOException {
+        IgniteUtils.setCurrentIgniteName(ignite.configuration().getIgniteInstanceName());
+
+        int ptsCnt = 40_000;
+        int featCnt = 28 * 28;
+
+        Properties props = loadMNISTProperties();
+
+        Stream<DenseLocalOnHeapVector> trainingMnistStream = MnistUtils.mnist(props.getProperty(PROP_TRAINING_IMAGES), props.getProperty(PROP_TRAINING_LABELS), new Random(123L), ptsCnt);
+        Stream<DenseLocalOnHeapVector> testMnistStream = MnistUtils.mnist(props.getProperty(PROP_TEST_IMAGES), props.getProperty(PROP_TEST_LABELS), new Random(123L), 10_000);
+
+        IgniteCache<BiIndex, Double> cache = createBiIndexedCache();
+
+        loadVectorsIntoBiIndexedCache(cache.getName(), trainingMnistStream.iterator(), featCnt + 1);
+
+        ColumnDecisionTreeTrainer<GiniSplitCalculator.GiniData> trainer =
+            new ColumnDecisionTreeTrainer<>(10, ContinuousSplitCalculators.GINI.apply(ignite), RegionCalculators.GINI, RegionCalculators.MOST_COMMON, ignite);
+
+        System.out.println(">>> Training started");
+        long before = System.currentTimeMillis();
+        DecisionTreeModel mdl = trainer.train(new BiIndexedCacheColumnDecisionTreeTrainerInput(cache, new HashMap<>(), ptsCnt, featCnt));
+        System.out.println(">>> Training finished in " + (System.currentTimeMillis() - before));
+
+        IgniteTriFunction<Model<Vector, Double>, Stream<IgniteBiTuple<Vector, Double>>, Function<Double, Double>, Double> mse = Estimators.errorsPercentage();
+        Double accuracy = mse.apply(mdl, testMnistStream.map(v -> new IgniteBiTuple<>(v.viewPart(0, featCnt), v.getX(featCnt))), Function.identity());
+        System.out.println(">>> Errs percentage: " + accuracy);
+
+        Assert.assertEquals(0, SplitCache.getOrCreate(ignite).size());
+        Assert.assertEquals(0, FeaturesCache.getOrCreate(ignite).size());
+        Assert.assertEquals(0, ContextCache.getOrCreate(ignite).size());
+        Assert.assertEquals(0, ProjectionsCache.getOrCreate(ignite).size());
+    }
+
+    /**
+     * Run decision tree classifier on MNIST using sparse distributed matrix as a storage for dataset.
+     * To run this test rename this method so it starts from 'test'.
+     *
+     * @throws IOException In case of loading MNIST dataset errors.
+     */
+    public void tstMNISTSparseDistributedMatrix() throws IOException {
+        IgniteUtils.setCurrentIgniteName(ignite.configuration().getIgniteInstanceName());
+
+        int ptsCnt = 30_000;
+        int featCnt = 28 * 28;
+
+        Properties props = loadMNISTProperties();
+
+        Stream<DenseLocalOnHeapVector> trainingMnistStream = MnistUtils.mnist(props.getProperty(PROP_TRAINING_IMAGES), props.getProperty(PROP_TRAINING_LABELS), new Random(123L), ptsCnt);
+        Stream<DenseLocalOnHeapVector> testMnistStream = MnistUtils.mnist(props.getProperty(PROP_TEST_IMAGES), props.getProperty(PROP_TEST_LABELS), new Random(123L), 10_000);
+
+        SparseDistributedMatrix m = new SparseDistributedMatrix(ptsCnt, featCnt + 1, StorageConstants.COLUMN_STORAGE_MODE, StorageConstants.RANDOM_ACCESS_MODE);
+
+        SparseDistributedMatrixStorage sto = (SparseDistributedMatrixStorage)m.getStorage();
+
+        loadVectorsIntoSparseDistributedMatrixCache(sto.cache().getName(), sto.getUUID(), trainingMnistStream.iterator(), featCnt + 1);
+
+        ColumnDecisionTreeTrainer<GiniSplitCalculator.GiniData> trainer =
+            new ColumnDecisionTreeTrainer<>(10, ContinuousSplitCalculators.GINI.apply(ignite), RegionCalculators.GINI, RegionCalculators.MOST_COMMON, ignite);
+
+        System.out.println(">>> Training started");
+        long before = System.currentTimeMillis();
+        DecisionTreeModel mdl = trainer.train(new MatrixColumnDecisionTreeTrainerInput(m, new HashMap<>()));
+        System.out.println(">>> Training finished in " + (System.currentTimeMillis() - before));
+
+        IgniteTriFunction<Model<Vector, Double>, Stream<IgniteBiTuple<Vector, Double>>, Function<Double, Double>, Double> mse = Estimators.errorsPercentage();
+        Double accuracy = mse.apply(mdl, testMnistStream.map(v -> new IgniteBiTuple<>(v.viewPart(0, featCnt), v.getX(featCnt))), Function.identity());
+        System.out.println(">>> Errs percentage: " + accuracy);
+
+        Assert.assertEquals(0, SplitCache.getOrCreate(ignite).size());
+        Assert.assertEquals(0, FeaturesCache.getOrCreate(ignite).size());
+        Assert.assertEquals(0, ContextCache.getOrCreate(ignite).size());
+        Assert.assertEquals(0, ProjectionsCache.getOrCreate(ignite).size());
+    }
+
+    /** Load properties for MNIST tests. */
+    private static Properties loadMNISTProperties() throws IOException {
+        Properties res = new Properties();
+
+        InputStream is = ColumnDecisionTreeTrainerBenchmark.class.getClassLoader().getResourceAsStream("manualrun/trees/columntrees.manualrun.properties");
+
+        res.load(is);
+
+        return res;
+    }
+
+    /** */
+    private void testByGenStreamerLoad(int ptsPerReg, HashMap<Integer, Integer> catsInfo,
+        SplitDataGenerator<DenseLocalOnHeapVector> gen, Random rnd) {
+
+        List<IgniteBiTuple<Integer, DenseLocalOnHeapVector>> lst = gen.
+            points(ptsPerReg, (i, rn) -> i).
+            collect(Collectors.toList());
+
+        int featCnt = gen.featuresCnt();
+
+        Collections.shuffle(lst, rnd);
+
+        int numRegs = gen.regsCount();
+
+        SparseDistributedMatrix m = new SparseDistributedMatrix(numRegs * ptsPerReg, featCnt + 1, StorageConstants.COLUMN_STORAGE_MODE, StorageConstants.RANDOM_ACCESS_MODE);
+
+        IgniteFunction<DoubleStream, Double> regCalc = s -> s.average().orElse(0.0);
+
+        Map<Integer, List<LabeledVectorDouble>> byRegion = new HashMap<>();
+
+        SparseDistributedMatrixStorage sto = (SparseDistributedMatrixStorage)m.getStorage();
+        long before = System.currentTimeMillis();
+        System.out.println(">>> Batch loading started...");
+        loadVectorsIntoSparseDistributedMatrixCache(sto.cache().getName(), sto.getUUID(), gen.
+            points(ptsPerReg, (i, rn) -> i).map(IgniteBiTuple::get2).iterator(), featCnt + 1);
+        System.out.println(">>> Batch loading took " + (System.currentTimeMillis() - before) + " ms.");
+
+        for (IgniteBiTuple<Integer, DenseLocalOnHeapVector> bt : lst) {
+            byRegion.putIfAbsent(bt.get1(), new LinkedList<>());
+            byRegion.get(bt.get1()).add(asLabeledVector(bt.get2().getStorage().data()));
+        }
+
+        ColumnDecisionTreeTrainer<VarianceSplitCalculator.VarianceData> trainer =
+            new ColumnDecisionTreeTrainer<>(2, ContinuousSplitCalculators.VARIANCE, RegionCalculators.VARIANCE, regCalc, ignite);
+
+        before = System.currentTimeMillis();
+        DecisionTreeModel mdl = trainer.train(new MatrixColumnDecisionTreeTrainerInput(m, catsInfo));
+
+        System.out.println(">>> Took time(ms): " + (System.currentTimeMillis() - before));
+
+        byRegion.keySet().forEach(k -> {
+            LabeledVectorDouble sp = byRegion.get(k).get(0);
+            Tracer.showAscii(sp.vector());
+            System.out.println("Prediction: " + mdl.predict(sp.vector()) + "label: " + sp.doubleLabel());
+            assert mdl.predict(sp.vector()) == sp.doubleLabel();
+        });
+    }
+
+    /**
+     * Test decision tree regression.
+     * To run this test rename this method so it starts from 'test'.
+     */
+    public void tstF1() {
+        IgniteUtils.setCurrentIgniteName(ignite.configuration().getIgniteInstanceName());
+        int ptsCnt = 10000;
+        Map<Integer, double[]> ranges = new HashMap<>();
+
+        ranges.put(0, new double[] {-100.0, 100.0});
+        ranges.put(1, new double[] {-100.0, 100.0});
+        ranges.put(2, new double[] {-100.0, 100.0});
+
+        int featCnt = 100;
+        double[] defRng = {-1.0, 1.0};
+
+        Vector[] trainVectors = vecsFromRanges(ranges, featCnt, defRng, new Random(123L), ptsCnt, f1);
+
+        SparseDistributedMatrix m = new SparseDistributedMatrix(ptsCnt, featCnt + 1, StorageConstants.COLUMN_STORAGE_MODE, StorageConstants.RANDOM_ACCESS_MODE);
+
+        SparseDistributedMatrixStorage sto = (SparseDistributedMatrixStorage)m.getStorage();
+
+        loadVectorsIntoSparseDistributedMatrixCache(sto.cache().getName(), sto.getUUID(), Arrays.stream(trainVectors).iterator(), featCnt + 1);
+
+        IgniteFunction<DoubleStream, Double> regCalc = s -> s.average().orElse(0.0);
+
+        ColumnDecisionTreeTrainer<VarianceSplitCalculator.VarianceData> trainer =
+            new ColumnDecisionTreeTrainer<>(10, ContinuousSplitCalculators.VARIANCE, RegionCalculators.VARIANCE, regCalc, ignite);
+
+        System.out.println(">>> Training started");
+        long before = System.currentTimeMillis();
+        DecisionTreeModel mdl = trainer.train(new MatrixColumnDecisionTreeTrainerInput(m, new HashMap<>()));
+        System.out.println(">>> Training finished in " + (System.currentTimeMillis() - before));
+
+        Vector[] testVectors = vecsFromRanges(ranges, featCnt, defRng, new Random(123L), 20, f1);
+
+        IgniteTriFunction<Model<Vector, Double>, Stream<IgniteBiTuple<Vector, Double>>, Function<Double, Double>, Double> mse = Estimators.MSE();
+        Double accuracy = mse.apply(mdl, Arrays.stream(testVectors).map(v -> new IgniteBiTuple<>(v.viewPart(0, featCnt), v.getX(featCnt))), Function.identity());
+        System.out.println(">>> MSE: " + accuracy);
+    }
+
+    /**
+     * Load vectors into sparse distributed matrix.
+     *
+     * @param cacheName Name of cache where matrix is stored.
+     * @param uuid UUID of matrix.
+     * @param iter Iterator over vectors.
+     * @param vectorSize size of vectors.
+     */
+    private void loadVectorsIntoSparseDistributedMatrixCache(String cacheName, UUID uuid,
+        Iterator<? extends org.apache.ignite.ml.math.Vector> iter, int vectorSize) {
+        try (IgniteDataStreamer<SparseMatrixKey, Map<Integer, Double>> streamer =
+                 Ignition.localIgnite().dataStreamer(cacheName)) {
+            int sampleIdx = 0;
+            streamer.allowOverwrite(true);
+
+            streamer.receiver(StreamTransformer.from((e, arg) -> {
+                Map<Integer, Double> val = e.getValue();
+
+                if (val == null)
+                    val = new Int2DoubleOpenHashMap();
+
+                val.putAll((Map<Integer, Double>)arg[0]);
+
+                e.setValue(val);
+
+                return null;
+            }));
+
+            // Feature index -> (sample index -> value)
+            Map<Integer, Map<Integer, Double>> batch = new HashMap<>();
+            IntStream.range(0, vectorSize).forEach(i -> batch.put(i, new HashMap<>()));
+            int batchSize = 1000;
+
+            while (iter.hasNext()) {
+                org.apache.ignite.ml.math.Vector next = iter.next();
+
+                for (int i = 0; i < vectorSize; i++)
+                    batch.get(i).put(sampleIdx, next.getX(i));
+
+                System.out.println(sampleIdx);
+                if (sampleIdx % batchSize == 0) {
+                    batch.keySet().forEach(fi -> streamer.addData(new SparseMatrixKey(fi, uuid, fi), batch.get(fi)));
+                    IntStream.range(0, vectorSize).forEach(i -> batch.put(i, new HashMap<>()));
+                }
+                sampleIdx++;
+            }
+            if (sampleIdx % batchSize != 0) {
+                batch.keySet().forEach(fi -> streamer.addData(new SparseMatrixKey(fi, uuid, fi), batch.get(fi)));
+                IntStream.range(0, vectorSize).forEach(i -> batch.put(i, new HashMap<>()));
+            }
+        }
+    }
+
+    /**
+     * Load vectors into bi-indexed cache.
+     *
+     * @param cacheName Name of cache.
+     * @param iter Iterator over vectors.
+     * @param vectorSize size of vectors.
+     */
+    private void loadVectorsIntoBiIndexedCache(String cacheName,
+        Iterator<? extends org.apache.ignite.ml.math.Vector> iter, int vectorSize) {
+        try (IgniteDataStreamer<BiIndex, Double> streamer =
+                 Ignition.localIgnite().dataStreamer(cacheName)) {
+            int sampleIdx = 0;
+
+            streamer.perNodeBufferSize(10000);
+
+            while (iter.hasNext()) {
+                org.apache.ignite.ml.math.Vector next = iter.next();
+
+                for (int i = 0; i < vectorSize; i++)
+                    streamer.addData(new BiIndex(sampleIdx, i), next.getX(i));
+
+                sampleIdx++;
+
+                if (sampleIdx % 1000 == 0)
+                    System.out.println(">>> Loaded " + sampleIdx + " vectors.");
+            }
+        }
+    }
+
+    /**
+     * Create bi-indexed cache for tests.
+     *
+     * @return Bi-indexed cache.
+     */
+    private IgniteCache<BiIndex, Double> createBiIndexedCache() {
+        CacheConfiguration<BiIndex, Double> cfg = new CacheConfiguration<>();
+
+        // Write to primary.
+        cfg.setWriteSynchronizationMode(CacheWriteSynchronizationMode.PRIMARY_SYNC);
+
+        // Atomic transactions only.
+        cfg.setAtomicityMode(CacheAtomicityMode.ATOMIC);
+
+        // No eviction.
+        cfg.setEvictionPolicy(null);
+
+        // No copying of values.
+        cfg.setCopyOnRead(false);
+
+        // Cache is partitioned.
+        cfg.setCacheMode(CacheMode.PARTITIONED);
+
+        cfg.setBackups(0);
+
+        cfg.setName("TMP_BI_INDEXED_CACHE");
+
+        return Ignition.localIgnite().getOrCreateCache(cfg);
+    }
+
+    /** */
+    private Vector[] vecsFromRanges(Map<Integer, double[]> ranges, int featCnt, double[] defRng, Random rnd, int ptsCnt,
+        Function<Vector, Double> f) {
+        int vs = featCnt + 1;
+        DenseLocalOnHeapVector[] res = new DenseLocalOnHeapVector[ptsCnt];
+        for (int pt = 0; pt < ptsCnt; pt++) {
+            DenseLocalOnHeapVector v = new DenseLocalOnHeapVector(vs);
+            for (int i = 0; i < featCnt; i++) {
+                double[] range = ranges.getOrDefault(i, defRng);
+                double from = range[0];
+                double to = range[1];
+                double rng = to - from;
+
+                v.setX(i, rnd.nextDouble() * rng);
+            }
+            v.setX(featCnt, f.apply(v));
+            res[pt] = v;
+        }
+
+        return res;
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/test/resources/manualrun/trees/columntrees.manualrun.properties
----------------------------------------------------------------------
diff --git a/modules/ml/src/test/resources/manualrun/trees/columntrees.manualrun.properties b/modules/ml/src/test/resources/manualrun/trees/columntrees.manualrun.properties
new file mode 100644
index 0000000..7040010
--- /dev/null
+++ b/modules/ml/src/test/resources/manualrun/trees/columntrees.manualrun.properties
@@ -0,0 +1,5 @@
+# Paths to mnist dataset parts.
+mnist.training.images=/path/to/train-images-idx3-ubyte
+mnist.training.labels=/path/to/train-labels-idx1-ubyte
+mnist.test.images=/path/to/t10k-images-idx3-ubyte
+mnist.test.labels=/path/to/t10k-labels-idx1-ubyte
\ No newline at end of file


[4/4] ignite git commit: IGNITE-5218: First version of decision trees. This closes #2936

Posted by is...@apache.org.
IGNITE-5218: First version of decision trees.
This closes #2936


Project: http://git-wip-us.apache.org/repos/asf/ignite/repo
Commit: http://git-wip-us.apache.org/repos/asf/ignite/commit/db7697b1
Tree: http://git-wip-us.apache.org/repos/asf/ignite/tree/db7697b1
Diff: http://git-wip-us.apache.org/repos/asf/ignite/diff/db7697b1

Branch: refs/heads/master
Commit: db7697b17cf6eb94754edb2b5e200655a3610dc1
Parents: 6579e69
Author: Artem Malykh <am...@gridgain.com>
Authored: Fri Nov 10 18:03:33 2017 +0300
Committer: Igor Sapego <is...@gridgain.com>
Committed: Fri Nov 10 18:03:33 2017 +0300

----------------------------------------------------------------------
 .gitignore                                      |   2 +
 examples/pom.xml                                |   5 +
 .../examples/ml/math/trees/MNISTExample.java    | 261 +++++++++
 .../examples/ml/math/trees/package-info.java    |  22 +
 modules/ml/licenses/netlib-java-bsd3.txt        |  51 ++
 modules/ml/pom.xml                              |  12 +-
 .../main/java/org/apache/ignite/ml/Model.java   |   4 +-
 .../main/java/org/apache/ignite/ml/Trainer.java |  30 +
 .../clustering/KMeansDistributedClusterer.java  |  19 +-
 .../apache/ignite/ml/estimators/Estimators.java |  50 ++
 .../ignite/ml/estimators/package-info.java      |  22 +
 .../ignite/ml/math/distributed/CacheUtils.java  | 178 +++++-
 .../math/distributed/keys/MatrixCacheKey.java   |   6 +-
 .../distributed/keys/impl/BlockMatrixKey.java   |  17 +-
 .../distributed/keys/impl/SparseMatrixKey.java  |  59 +-
 .../ignite/ml/math/functions/Functions.java     |  38 ++
 .../ml/math/functions/IgniteBinaryOperator.java |  29 +
 .../math/functions/IgniteCurriedBiFunction.java |  29 +
 .../ml/math/functions/IgniteSupplier.java       |  30 +
 .../math/functions/IgniteToDoubleFunction.java  |  25 +
 .../matrix/SparseBlockDistributedMatrix.java    |   4 +-
 .../impls/matrix/SparseDistributedMatrix.java   |   3 +-
 .../storage/matrix/BlockMatrixStorage.java      |  12 +-
 .../matrix/SparseDistributedMatrixStorage.java  |  17 +-
 .../ignite/ml/structures/LabeledVector.java     |  63 +++
 .../ml/structures/LabeledVectorDouble.java      |  46 ++
 .../ignite/ml/structures/package-info.java      |  22 +
 .../ignite/ml/trees/CategoricalRegionInfo.java  |  72 +++
 .../ignite/ml/trees/CategoricalSplitInfo.java   |  68 +++
 .../ignite/ml/trees/ContinuousRegionInfo.java   |  74 +++
 .../ml/trees/ContinuousSplitCalculator.java     |  50 ++
 .../org/apache/ignite/ml/trees/RegionInfo.java  |  62 +++
 .../ml/trees/models/DecisionTreeModel.java      |  44 ++
 .../ignite/ml/trees/models/package-info.java    |  22 +
 .../ml/trees/nodes/CategoricalSplitNode.java    |  50 ++
 .../ml/trees/nodes/ContinuousSplitNode.java     |  56 ++
 .../ignite/ml/trees/nodes/DecisionTreeNode.java |  33 ++
 .../org/apache/ignite/ml/trees/nodes/Leaf.java  |  49 ++
 .../apache/ignite/ml/trees/nodes/SplitNode.java | 100 ++++
 .../ignite/ml/trees/nodes/package-info.java     |  22 +
 .../apache/ignite/ml/trees/package-info.java    |  22 +
 .../ml/trees/trainers/columnbased/BiIndex.java  | 113 ++++
 ...exedCacheColumnDecisionTreeTrainerInput.java |  57 ++
 .../CacheColumnDecisionTreeTrainerInput.java    | 142 +++++
 .../columnbased/ColumnDecisionTreeTrainer.java  | 557 +++++++++++++++++++
 .../ColumnDecisionTreeTrainerInput.java         |  55 ++
 .../MatrixColumnDecisionTreeTrainerInput.java   |  82 +++
 .../trainers/columnbased/RegionProjection.java  | 109 ++++
 .../trainers/columnbased/TrainingContext.java   | 166 ++++++
 .../columnbased/caches/ContextCache.java        |  68 +++
 .../columnbased/caches/FeaturesCache.java       | 151 +++++
 .../columnbased/caches/ProjectionsCache.java    | 284 ++++++++++
 .../trainers/columnbased/caches/SplitCache.java | 206 +++++++
 .../ContinuousSplitCalculators.java             |  34 ++
 .../contsplitcalcs/GiniSplitCalculator.java     | 234 ++++++++
 .../contsplitcalcs/VarianceSplitCalculator.java | 179 ++++++
 .../contsplitcalcs/package-info.java            |  22 +
 .../trainers/columnbased/package-info.java      |  22 +
 .../columnbased/regcalcs/RegionCalculators.java |  85 +++
 .../columnbased/regcalcs/package-info.java      |  22 +
 .../vectors/CategoricalFeatureProcessor.java    | 211 +++++++
 .../vectors/ContinuousFeatureProcessor.java     | 111 ++++
 .../vectors/ContinuousSplitInfo.java            |  54 ++
 .../columnbased/vectors/FeatureProcessor.java   |  81 +++
 .../vectors/FeatureVectorProcessorUtils.java    |  57 ++
 .../columnbased/vectors/SampleInfo.java         |  80 +++
 .../trainers/columnbased/vectors/SplitInfo.java | 106 ++++
 .../columnbased/vectors/package-info.java       |  22 +
 .../org/apache/ignite/ml/util/MnistUtils.java   | 121 ++++
 .../java/org/apache/ignite/ml/util/Utils.java   |  53 ++
 .../org/apache/ignite/ml/IgniteMLTestSuite.java |   4 +-
 .../java/org/apache/ignite/ml/TestUtils.java    |  15 +
 .../SparseDistributedBlockMatrixTest.java       |   1 +
 .../ignite/ml/trees/BaseDecisionTreeTest.java   |  70 +++
 .../ml/trees/ColumnDecisionTreeTrainerTest.java | 190 +++++++
 .../ignite/ml/trees/DecisionTreesTestSuite.java |  33 ++
 .../ml/trees/GiniSplitCalculatorTest.java       | 141 +++++
 .../ignite/ml/trees/SplitDataGenerator.java     | 390 +++++++++++++
 .../ml/trees/VarianceSplitCalculatorTest.java   |  84 +++
 .../ColumnDecisionTreeTrainerBenchmark.java     | 455 +++++++++++++++
 .../trees/columntrees.manualrun.properties      |   5 +
 81 files changed, 6538 insertions(+), 114 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/.gitignore
----------------------------------------------------------------------
diff --git a/.gitignore b/.gitignore
index d8dd951..18146f8 100644
--- a/.gitignore
+++ b/.gitignore
@@ -89,3 +89,5 @@ packages
 /modules/platforms/cpp/odbc-test/ignite-odbc-tests
 /modules/platforms/cpp/stamp-h1
 
+#Files related to ML manual-runnable tests
+/modules/ml/src/test/resources/manualrun/trees/columntrees.manualrun.properties
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/examples/pom.xml
----------------------------------------------------------------------
diff --git a/examples/pom.xml b/examples/pom.xml
index 30d23ae..2b95e65 100644
--- a/examples/pom.xml
+++ b/examples/pom.xml
@@ -248,6 +248,11 @@
                     <artifactId>ignite-ml</artifactId>
                     <version>${project.version}</version>
                 </dependency>
+                <dependency>
+                    <groupId>commons-cli</groupId>
+                    <artifactId>commons-cli</artifactId>
+                    <version>1.2</version>
+                </dependency>
             </dependencies>
         </profile>
 

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/examples/src/main/ml/org/apache/ignite/examples/ml/math/trees/MNISTExample.java
----------------------------------------------------------------------
diff --git a/examples/src/main/ml/org/apache/ignite/examples/ml/math/trees/MNISTExample.java b/examples/src/main/ml/org/apache/ignite/examples/ml/math/trees/MNISTExample.java
new file mode 100644
index 0000000..6aaadd9
--- /dev/null
+++ b/examples/src/main/ml/org/apache/ignite/examples/ml/math/trees/MNISTExample.java
@@ -0,0 +1,261 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.examples.ml.math.trees;
+
+import java.io.IOException;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.Random;
+import java.util.function.Function;
+import java.util.stream.Stream;
+import org.apache.commons.cli.BasicParser;
+import org.apache.commons.cli.CommandLine;
+import org.apache.commons.cli.CommandLineParser;
+import org.apache.commons.cli.Option;
+import org.apache.commons.cli.OptionBuilder;
+import org.apache.commons.cli.Options;
+import org.apache.commons.cli.ParseException;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.IgniteDataStreamer;
+import org.apache.ignite.Ignition;
+import org.apache.ignite.cache.CacheAtomicityMode;
+import org.apache.ignite.cache.CacheMode;
+import org.apache.ignite.cache.CacheWriteSynchronizationMode;
+import org.apache.ignite.configuration.CacheConfiguration;
+import org.apache.ignite.examples.ExampleNodeStartup;
+import org.apache.ignite.internal.util.IgniteUtils;
+import org.apache.ignite.lang.IgniteBiTuple;
+import org.apache.ignite.ml.Model;
+import org.apache.ignite.ml.estimators.Estimators;
+import org.apache.ignite.ml.math.Vector;
+import org.apache.ignite.ml.math.functions.IgniteTriFunction;
+import org.apache.ignite.ml.math.impls.vector.DenseLocalOnHeapVector;
+import org.apache.ignite.ml.trees.models.DecisionTreeModel;
+import org.apache.ignite.ml.trees.trainers.columnbased.BiIndex;
+import org.apache.ignite.ml.trees.trainers.columnbased.BiIndexedCacheColumnDecisionTreeTrainerInput;
+import org.apache.ignite.ml.trees.trainers.columnbased.ColumnDecisionTreeTrainer;
+import org.apache.ignite.ml.trees.trainers.columnbased.contsplitcalcs.ContinuousSplitCalculators;
+import org.apache.ignite.ml.trees.trainers.columnbased.contsplitcalcs.GiniSplitCalculator;
+import org.apache.ignite.ml.trees.trainers.columnbased.regcalcs.RegionCalculators;
+import org.apache.ignite.ml.util.MnistUtils;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * <p>
+ * Example of usage of decision trees algorithm for MNIST dataset
+ * (it can be found here: http://yann.lecun.com/exdb/mnist/). </p>
+ * <p>
+ * Remote nodes should always be started with special configuration file which
+ * enables P2P class loading: {@code 'ignite.{sh|bat} examples/config/example-ignite.xml'}.</p>
+ * <p>
+ * Alternatively you can run {@link ExampleNodeStartup} in another JVM which will start node
+ * with {@code examples/config/example-ignite.xml} configuration.</p>
+ * <p>
+ * It is recommended to start at least one node prior to launching this example if you intend
+ * to run it with default memory settings.</p>
+ * <p>
+ * This example should with program arguments, for example
+ * -ts_i /path/to/train-images-idx3-ubyte
+ * -ts_l /path/to/train-labels-idx1-ubyte
+ * -tss_i /path/to/t10k-images-idx3-ubyte
+ * -tss_l /path/to/t10k-labels-idx1-ubyte
+ * -cfg examples/config/example-ignite.xml.</p>
+ * <p>
+ * -ts_i specifies path to training set images of MNIST;
+ * -ts_l specifies path to training set labels of MNIST;
+ * -tss_i specifies path to test set images of MNIST;
+ * -tss_l specifies path to test set labels of MNIST;
+ * -cfg specifies path to a config path.</p>
+ */
+public class MNISTExample {
+    /** Name of parameter specifying path to training set images. */
+    private static final String MNIST_TRAINING_IMAGES_PATH = "ts_i";
+
+    /** Name of parameter specifying path to training set labels. */
+    private static final String MNIST_TRAINING_LABELS_PATH = "ts_l";
+
+    /** Name of parameter specifying path to test set images. */
+    private static final String MNIST_TEST_IMAGES_PATH = "tss_i";
+
+    /** Name of parameter specifying path to test set labels. */
+    private static final String MNIST_TEST_LABELS_PATH = "tss_l";
+
+    /** Name of parameter specifying path of Ignite config. */
+    private static final String CONFIG = "cfg";
+
+    /** Default config path. */
+    private static final String DEFAULT_CONFIG = "examples/config/example-ignite.xml";
+
+    /**
+     * Launches example.
+     *
+     * @param args Program arguments.
+     */
+    public static void main(String[] args) {
+        String igniteCfgPath;
+
+        CommandLineParser parser = new BasicParser();
+
+        String trainingImagesPath;
+        String trainingLabelsPath;
+
+        String testImagesPath;
+        String testLabelsPath;
+
+        try {
+            // Parse the command line arguments.
+            CommandLine line = parser.parse(buildOptions(), args);
+
+            trainingImagesPath = line.getOptionValue(MNIST_TRAINING_IMAGES_PATH);
+            trainingLabelsPath = line.getOptionValue(MNIST_TRAINING_LABELS_PATH);
+            testImagesPath = line.getOptionValue(MNIST_TEST_IMAGES_PATH);
+            testLabelsPath = line.getOptionValue(MNIST_TEST_LABELS_PATH);
+            igniteCfgPath = line.getOptionValue(CONFIG, DEFAULT_CONFIG);
+        }
+        catch (ParseException e) {
+            e.printStackTrace();
+            return;
+        }
+
+        try (Ignite ignite = Ignition.start(igniteCfgPath)) {
+            IgniteUtils.setCurrentIgniteName(ignite.configuration().getIgniteInstanceName());
+
+            int ptsCnt = 60000;
+            int featCnt = 28 * 28;
+
+            Stream<DenseLocalOnHeapVector> trainingMnistStream = MnistUtils.mnist(trainingImagesPath, trainingLabelsPath, new Random(123L), ptsCnt);
+            Stream<DenseLocalOnHeapVector> testMnistStream = MnistUtils.mnist(testImagesPath, testLabelsPath, new Random(123L), 10_000);
+
+            IgniteCache<BiIndex, Double> cache = createBiIndexedCache(ignite);
+
+            loadVectorsIntoBiIndexedCache(cache.getName(), trainingMnistStream.iterator(), featCnt + 1, ignite);
+
+            ColumnDecisionTreeTrainer<GiniSplitCalculator.GiniData> trainer =
+                new ColumnDecisionTreeTrainer<>(10, ContinuousSplitCalculators.GINI.apply(ignite), RegionCalculators.GINI, RegionCalculators.MOST_COMMON, ignite);
+
+            System.out.println(">>> Training started");
+            long before = System.currentTimeMillis();
+            DecisionTreeModel mdl = trainer.train(new BiIndexedCacheColumnDecisionTreeTrainerInput(cache, new HashMap<>(), ptsCnt, featCnt));
+            System.out.println(">>> Training finished in " + (System.currentTimeMillis() - before));
+
+            IgniteTriFunction<Model<Vector, Double>, Stream<IgniteBiTuple<Vector, Double>>, Function<Double, Double>, Double> mse = Estimators.errorsPercentage();
+            Double accuracy = mse.apply(mdl, testMnistStream.map(v -> new IgniteBiTuple<>(v.viewPart(0, featCnt), v.getX(featCnt))), Function.identity());
+            System.out.println(">>> Errs percentage: " + accuracy);
+        }
+        catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    /**
+     * Build cli options.
+     */
+    @NotNull private static Options buildOptions() {
+        Options options = new Options();
+
+        Option trsImagesPathOpt = OptionBuilder.withArgName(MNIST_TRAINING_IMAGES_PATH).withLongOpt(MNIST_TRAINING_IMAGES_PATH).hasArg()
+            .withDescription("Path to the MNIST training set.")
+            .isRequired(true).create();
+
+        Option trsLabelsPathOpt = OptionBuilder.withArgName(MNIST_TRAINING_LABELS_PATH).withLongOpt(MNIST_TRAINING_LABELS_PATH).hasArg()
+            .withDescription("Path to the MNIST training set.")
+            .isRequired(true).create();
+
+        Option tssImagesPathOpt = OptionBuilder.withArgName(MNIST_TEST_IMAGES_PATH).withLongOpt(MNIST_TEST_IMAGES_PATH).hasArg()
+            .withDescription("Path to the MNIST test set.")
+            .isRequired(true).create();
+
+        Option tssLabelsPathOpt = OptionBuilder.withArgName(MNIST_TEST_LABELS_PATH).withLongOpt(MNIST_TEST_LABELS_PATH).hasArg()
+            .withDescription("Path to the MNIST test set.")
+            .isRequired(true).create();
+
+        Option configOpt = OptionBuilder.withArgName(CONFIG).withLongOpt(CONFIG).hasArg()
+            .withDescription("Path to the config.")
+            .isRequired(false).create();
+
+        options.addOption(trsImagesPathOpt);
+        options.addOption(trsLabelsPathOpt);
+        options.addOption(tssImagesPathOpt);
+        options.addOption(tssLabelsPathOpt);
+        options.addOption(configOpt);
+
+        return options;
+    }
+
+    /**
+     * Creates cache where data for training is stored.
+     *
+     * @param ignite Ignite instance.
+     * @return cache where data for training is stored.
+     */
+    private static IgniteCache<BiIndex, Double> createBiIndexedCache(Ignite ignite) {
+        CacheConfiguration<BiIndex, Double> cfg = new CacheConfiguration<>();
+
+        // Write to primary.
+        cfg.setWriteSynchronizationMode(CacheWriteSynchronizationMode.PRIMARY_SYNC);
+
+        // Atomic transactions only.
+        cfg.setAtomicityMode(CacheAtomicityMode.ATOMIC);
+
+        // No eviction.
+        cfg.setEvictionPolicy(null);
+
+        // No copying of values.
+        cfg.setCopyOnRead(false);
+
+        // Cache is partitioned.
+        cfg.setCacheMode(CacheMode.PARTITIONED);
+
+        cfg.setBackups(0);
+
+        cfg.setName("TMP_BI_INDEXED_CACHE");
+
+        return ignite.getOrCreateCache(cfg);
+    }
+
+    /**
+     * Loads vectors into cache.
+     *
+     * @param cacheName Name of cache.
+     * @param vectorsIterator Iterator over vectors to load.
+     * @param vectorSize Size of vector.
+     * @param ignite Ignite instance.
+     */
+    private static void loadVectorsIntoBiIndexedCache(String cacheName, Iterator<? extends Vector> vectorsIterator,
+        int vectorSize, Ignite ignite) {
+        try (IgniteDataStreamer<BiIndex, Double> streamer =
+                 ignite.dataStreamer(cacheName)) {
+            int sampleIdx = 0;
+
+            streamer.perNodeBufferSize(10000);
+
+            while (vectorsIterator.hasNext()) {
+                org.apache.ignite.ml.math.Vector next = vectorsIterator.next();
+
+                for (int i = 0; i < vectorSize; i++)
+                    streamer.addData(new BiIndex(sampleIdx, i), next.getX(i));
+
+                sampleIdx++;
+
+                if (sampleIdx % 1000 == 0)
+                    System.out.println("Loaded " + sampleIdx + " vectors.");
+            }
+        }
+    }
+}
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/examples/src/main/ml/org/apache/ignite/examples/ml/math/trees/package-info.java
----------------------------------------------------------------------
diff --git a/examples/src/main/ml/org/apache/ignite/examples/ml/math/trees/package-info.java b/examples/src/main/ml/org/apache/ignite/examples/ml/math/trees/package-info.java
new file mode 100644
index 0000000..9b6867b
--- /dev/null
+++ b/examples/src/main/ml/org/apache/ignite/examples/ml/math/trees/package-info.java
@@ -0,0 +1,22 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * <!-- Package description. -->
+ * Decision trees examples.
+ */
+package org.apache.ignite.examples.ml.math.trees;

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/licenses/netlib-java-bsd3.txt
----------------------------------------------------------------------
diff --git a/modules/ml/licenses/netlib-java-bsd3.txt b/modules/ml/licenses/netlib-java-bsd3.txt
new file mode 100644
index 0000000..d6b30c1
--- /dev/null
+++ b/modules/ml/licenses/netlib-java-bsd3.txt
@@ -0,0 +1,51 @@
+This product binaries redistribute netlib-java which is available under the following license:
+
+Copyright (c) 2013 Samuel Halliday
+Copyright (c) 1992-2011 The University of Tennessee and The University
+                        of Tennessee Research Foundation.  All rights
+                        reserved.
+Copyright (c) 2000-2011 The University of California Berkeley. All
+                        rights reserved.
+Copyright (c) 2006-2011 The University of Colorado Denver.  All rights
+                        reserved.
+
+$COPYRIGHT$
+
+Additional copyrights may follow
+
+$HEADER$
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+- Redistributions of source code must retain the above copyright
+  notice, this list of conditions and the following disclaimer.
+
+- Redistributions in binary form must reproduce the above copyright
+  notice, this list of conditions and the following disclaimer listed
+  in this license in the documentation and/or other materials
+  provided with the distribution.
+
+- Neither the name of the copyright holders nor the names of its
+  contributors may be used to endorse or promote products derived from
+  this software without specific prior written permission.
+
+The copyright holders provide no reassurances that the source code
+provided does not infringe any patent, copyright, or any other
+intellectual property rights of third parties.  The copyright holders
+disclaim any liability to any recipient for claims brought against
+recipient by any third party for infringement of that parties
+intellectual property rights.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/pom.xml
----------------------------------------------------------------------
diff --git a/modules/ml/pom.xml b/modules/ml/pom.xml
index 94cfc51..c495f44 100644
--- a/modules/ml/pom.xml
+++ b/modules/ml/pom.xml
@@ -75,13 +75,6 @@
 
         <dependency>
             <groupId>org.springframework</groupId>
-            <artifactId>spring-beans</artifactId>
-            <version>${spring.version}</version>
-            <scope>test</scope>
-        </dependency>
-
-        <dependency>
-            <groupId>org.springframework</groupId>
             <artifactId>spring-context</artifactId>
             <version>${spring.version}</version>
             <scope>test</scope>
@@ -105,6 +98,11 @@
             <version>1.0</version>
         </dependency>
 
+        <dependency>
+            <groupId>com.zaxxer</groupId>
+            <artifactId>SparseBitSet</artifactId>
+            <version>1.0</version>
+        </dependency>
     </dependencies>
 
     <profiles>

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/Model.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/Model.java b/modules/ml/src/main/java/org/apache/ignite/ml/Model.java
index 3c60bfa..05ce774 100644
--- a/modules/ml/src/main/java/org/apache/ignite/ml/Model.java
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/Model.java
@@ -24,7 +24,7 @@ import java.util.function.BiFunction;
 @FunctionalInterface
 public interface Model<T, V> extends Serializable {
     /** Predict a result for value. */
-    public V predict(T val);
+    V predict(T val);
 
     /**
      * Combines this model with other model via specified combiner
@@ -33,7 +33,7 @@ public interface Model<T, V> extends Serializable {
      * @param combiner Combiner.
      * @return Combination of models.
      */
-    public default <X, W> Model<T, X> combine(Model<T, W> other, BiFunction<V, W, X> combiner) {
+    default <X, W> Model<T, X> combine(Model<T, W> other, BiFunction<V, W, X> combiner) {
         return v -> combiner.apply(predict(v), other.predict(v));
     }
 }

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/Trainer.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/Trainer.java b/modules/ml/src/main/java/org/apache/ignite/ml/Trainer.java
new file mode 100644
index 0000000..795e218
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/Trainer.java
@@ -0,0 +1,30 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml;
+
+import org.apache.ignite.ml.trees.trainers.columnbased.ColumnDecisionTreeTrainer;
+
+/**
+ * Interface for Trainers. Trainer is just a function which produces model from the data.
+ * See for example {@link ColumnDecisionTreeTrainer}.
+ * @param <M> Type of produced model.
+ * @param <T> Type of data needed for model producing.
+ */
+public interface Trainer<M extends Model, T> {
+    M train(T data);
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/clustering/KMeansDistributedClusterer.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/clustering/KMeansDistributedClusterer.java b/modules/ml/src/main/java/org/apache/ignite/ml/clustering/KMeansDistributedClusterer.java
index d6a3fc3..6c25edc 100644
--- a/modules/ml/src/main/java/org/apache/ignite/ml/clustering/KMeansDistributedClusterer.java
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/clustering/KMeansDistributedClusterer.java
@@ -21,6 +21,7 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 import java.util.Random;
+import java.util.UUID;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.stream.Collectors;
 import javax.cache.Cache;
@@ -94,7 +95,7 @@ public class KMeansDistributedClusterer extends BaseKMeansClusterer<SparseDistri
         boolean converged = false;
         int iteration = 0;
         int dim = pointsCp.viewRow(0).size();
-        IgniteUuid uid = pointsCp.getUUID();
+        UUID uid = pointsCp.getUUID();
 
         // Execute iterations of Lloyd's algorithm until converged
         while (iteration < maxIterations && !converged) {
@@ -140,7 +141,7 @@ public class KMeansDistributedClusterer extends BaseKMeansClusterer<SparseDistri
         // to their squared distance from the centers. Note that only distances between points
         // and new centers are computed in each iteration.
         int step = 0;
-        IgniteUuid uid = points.getUUID();
+        UUID uid = points.getUUID();
 
         while (step < initSteps) {
             // We assume here that costs can fit into memory of one node.
@@ -180,7 +181,7 @@ public class KMeansDistributedClusterer extends BaseKMeansClusterer<SparseDistri
     }
 
     /** */
-    private List<Vector> getNewCenters(int k, ConcurrentHashMap<Integer, Double> costs, IgniteUuid uid,
+    private List<Vector> getNewCenters(int k, ConcurrentHashMap<Integer, Double> costs, UUID uid,
         double sumCosts, String cacheName) {
         return distributedFold(cacheName,
             (IgniteBiFunction<Cache.Entry<SparseMatrixKey, Map<Integer, Double>>,
@@ -200,7 +201,7 @@ public class KMeansDistributedClusterer extends BaseKMeansClusterer<SparseDistri
                 list1.addAll(list2);
                 return list1;
             },
-            new ArrayList<>()
+            ArrayList::new
         );
     }
 
@@ -219,11 +220,11 @@ public class KMeansDistributedClusterer extends BaseKMeansClusterer<SparseDistri
             (map1, map2) -> {
                 map1.putAll(map2);
                 return map1;
-            }, new ConcurrentHashMap<>());
+            }, ConcurrentHashMap::new);
     }
 
     /** */
-    private ConcurrentHashMap<Integer, Integer> weightCenters(IgniteUuid uid, List<Vector> distinctCenters, String cacheName) {
+    private ConcurrentHashMap<Integer, Integer> weightCenters(UUID uid, List<Vector> distinctCenters, String cacheName) {
         return distributedFold(cacheName,
             (IgniteBiFunction<Cache.Entry<SparseMatrixKey, Map<Integer, Double>>,
                 ConcurrentHashMap<Integer, Integer>,
@@ -249,7 +250,7 @@ public class KMeansDistributedClusterer extends BaseKMeansClusterer<SparseDistri
             key -> key.matrixId().equals(uid),
             (map1, map2) -> MapUtil.mergeMaps(map1, map2, (integer, integer2) -> integer2 + integer,
                 ConcurrentHashMap::new),
-            new ConcurrentHashMap<>());
+            ConcurrentHashMap::new);
     }
 
     /** */
@@ -258,7 +259,7 @@ public class KMeansDistributedClusterer extends BaseKMeansClusterer<SparseDistri
     }
 
     /** */
-    private SumsAndCounts getSumsAndCounts(Vector[] centers, int dim, IgniteUuid uid, String cacheName) {
+    private SumsAndCounts getSumsAndCounts(Vector[] centers, int dim, UUID uid, String cacheName) {
         return CacheUtils.distributedFold(cacheName,
             (IgniteBiFunction<Cache.Entry<SparseMatrixKey, Map<Integer, Double>>, SumsAndCounts, SumsAndCounts>)(entry, counts) -> {
                 Map<Integer, Double> vec = entry.getValue();
@@ -278,7 +279,7 @@ public class KMeansDistributedClusterer extends BaseKMeansClusterer<SparseDistri
                 return counts;
             },
             key -> key.matrixId().equals(uid),
-            SumsAndCounts::merge, new SumsAndCounts()
+            SumsAndCounts::merge, SumsAndCounts::new
         );
     }
 

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/estimators/Estimators.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/estimators/Estimators.java b/modules/ml/src/main/java/org/apache/ignite/ml/estimators/Estimators.java
new file mode 100644
index 0000000..13331d1
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/estimators/Estimators.java
@@ -0,0 +1,50 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.estimators;
+
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.Function;
+import java.util.stream.Stream;
+import org.apache.ignite.lang.IgniteBiTuple;
+import org.apache.ignite.ml.Model;
+import org.apache.ignite.ml.math.functions.IgniteTriFunction;
+
+/** Estimators. */
+public class Estimators {
+    /** Simple implementation of mean squared error estimator. */
+    public static <T, V> IgniteTriFunction<Model<T, V>, Stream<IgniteBiTuple<T, V>>, Function<V, Double>, Double> MSE() {
+        return (model, stream, f) -> stream.mapToDouble(dp -> {
+            double diff = f.apply(dp.get2()) - f.apply(model.predict(dp.get1()));
+            return diff * diff;
+        }).average().orElse(0);
+    }
+
+    /** Simple implementation of errors percentage estimator. */
+    public static <T, V> IgniteTriFunction<Model<T, V>, Stream<IgniteBiTuple<T, V>>, Function<V, Double>, Double> errorsPercentage() {
+        return (model, stream, f) -> {
+            AtomicLong total = new AtomicLong(0);
+
+            long cnt = stream.
+                peek((ib) -> total.incrementAndGet()).
+                filter(dp -> !model.predict(dp.get1()).equals(dp.get2())).
+                count();
+
+            return (double)cnt / total.get();
+        };
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/estimators/package-info.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/estimators/package-info.java b/modules/ml/src/main/java/org/apache/ignite/ml/estimators/package-info.java
new file mode 100644
index 0000000..c03827f
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/estimators/package-info.java
@@ -0,0 +1,22 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * <!-- Package description. -->
+ * Contains estimation algorithms.
+ */
+package org.apache.ignite.ml.estimators;
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/CacheUtils.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/CacheUtils.java b/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/CacheUtils.java
index 8c8bba7..b9eb386 100644
--- a/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/CacheUtils.java
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/CacheUtils.java
@@ -21,7 +21,11 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.Map;
 import java.util.Objects;
+import java.util.Set;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.function.BinaryOperator;
+import java.util.stream.Stream;
 import javax.cache.Cache;
 import org.apache.ignite.Ignite;
 import org.apache.ignite.IgniteCache;
@@ -32,17 +36,21 @@ import org.apache.ignite.cluster.ClusterGroup;
 import org.apache.ignite.cluster.ClusterNode;
 import org.apache.ignite.internal.processors.cache.CacheEntryImpl;
 import org.apache.ignite.internal.util.typedef.internal.A;
+import org.apache.ignite.lang.IgniteBiTuple;
 import org.apache.ignite.lang.IgniteCallable;
 import org.apache.ignite.lang.IgnitePredicate;
 import org.apache.ignite.lang.IgniteRunnable;
 import org.apache.ignite.lang.IgniteUuid;
 import org.apache.ignite.ml.math.KeyMapper;
-import org.apache.ignite.ml.math.distributed.keys.RowColMatrixKey;
-import org.apache.ignite.ml.math.distributed.keys.impl.BlockMatrixKey;
+import org.apache.ignite.ml.math.distributed.keys.BlockMatrixKey;
+import org.apache.ignite.ml.math.distributed.keys.MatrixCacheKey;
 import org.apache.ignite.ml.math.functions.IgniteBiFunction;
+import org.apache.ignite.ml.math.functions.IgniteBinaryOperator;
 import org.apache.ignite.ml.math.functions.IgniteConsumer;
 import org.apache.ignite.ml.math.functions.IgniteDoubleFunction;
 import org.apache.ignite.ml.math.functions.IgniteFunction;
+import org.apache.ignite.ml.math.functions.IgniteSupplier;
+import org.apache.ignite.ml.math.functions.IgniteTriFunction;
 import org.apache.ignite.ml.math.impls.matrix.BlockEntry;
 
 /**
@@ -131,7 +139,7 @@ public class CacheUtils {
      * @return Sum obtained using sparse logic.
      */
     @SuppressWarnings("unchecked")
-    public static <K, V> double sparseSum(IgniteUuid matrixUuid, String cacheName) {
+    public static <K, V> double sparseSum(UUID matrixUuid, String cacheName) {
         A.notNull(matrixUuid, "matrixUuid");
         A.notNull(cacheName, "cacheName");
 
@@ -198,7 +206,7 @@ public class CacheUtils {
      * @return Minimum value obtained using sparse logic.
      */
     @SuppressWarnings("unchecked")
-    public static <K, V> double sparseMin(IgniteUuid matrixUuid, String cacheName) {
+    public static <K, V> double sparseMin(UUID matrixUuid, String cacheName) {
         A.notNull(matrixUuid, "matrixUuid");
         A.notNull(cacheName, "cacheName");
 
@@ -235,7 +243,7 @@ public class CacheUtils {
      * @return Maximum value obtained using sparse logic.
      */
     @SuppressWarnings("unchecked")
-    public static <K, V> double sparseMax(IgniteUuid matrixUuid, String cacheName) {
+    public static <K, V> double sparseMax(UUID matrixUuid, String cacheName) {
         A.notNull(matrixUuid, "matrixUuid");
         A.notNull(cacheName, "cacheName");
 
@@ -316,7 +324,7 @@ public class CacheUtils {
      * @param mapper Mapping {@link IgniteFunction}.
      */
     @SuppressWarnings("unchecked")
-    public static <K, V> void sparseMap(IgniteUuid matrixUuid, IgniteDoubleFunction<Double> mapper, String cacheName) {
+    public static <K, V> void sparseMap(UUID matrixUuid, IgniteDoubleFunction<Double> mapper, String cacheName) {
         A.notNull(matrixUuid, "matrixUuid");
         A.notNull(cacheName, "cacheName");
         A.notNull(mapper, "mapper");
@@ -350,12 +358,12 @@ public class CacheUtils {
      *
      * @param matrixUuid Matrix uuid.
      */
-    private static <K> IgnitePredicate<K> sparseKeyFilter(IgniteUuid matrixUuid) {
+    private static <K> IgnitePredicate<K> sparseKeyFilter(UUID matrixUuid) {
         return key -> {
-            if (key instanceof BlockMatrixKey)
-                return ((BlockMatrixKey)key).matrixId().equals(matrixUuid);
-            else if (key instanceof RowColMatrixKey)
-                return ((RowColMatrixKey)key).matrixId().equals(matrixUuid);
+            if (key instanceof MatrixCacheKey)
+                return ((MatrixCacheKey)key).matrixId().equals(matrixUuid);
+            else if (key instanceof IgniteBiTuple)
+                return ((IgniteBiTuple<Integer, UUID>)key).get2().equals(matrixUuid);
             else
                 throw new UnsupportedOperationException();
         };
@@ -404,6 +412,76 @@ public class CacheUtils {
     }
 
     /**
+     * @param cacheName Cache name.
+     * @param fun An operation that accepts a cache entry and processes it.
+     * @param ignite Ignite.
+     * @param keysGen Keys generator.
+     * @param <K> Cache key object type.
+     * @param <V> Cache value object type.
+     */
+    public static <K, V> void update(String cacheName, Ignite ignite,
+        IgniteBiFunction<Ignite, Cache.Entry<K, V>, Stream<Cache.Entry<K, V>>> fun, IgniteSupplier<Set<K>> keysGen) {
+        bcast(cacheName, ignite, () -> {
+            Ignite ig = Ignition.localIgnite();
+            IgniteCache<K, V> cache = ig.getOrCreateCache(cacheName);
+
+            Affinity<K> affinity = ig.affinity(cacheName);
+            ClusterNode locNode = ig.cluster().localNode();
+
+            Collection<K> ks = affinity.mapKeysToNodes(keysGen.get()).get(locNode);
+
+            if (ks == null)
+                return;
+
+            Map<K, V> m = new ConcurrentHashMap<>();
+
+            ks.parallelStream().forEach(k -> {
+                V v = cache.localPeek(k);
+                if (v != null)
+                    (fun.apply(ignite, new CacheEntryImpl<>(k, v))).forEach(ent -> m.put(ent.getKey(), ent.getValue()));
+            });
+
+            cache.putAll(m);
+        });
+    }
+
+    /**
+     * @param cacheName Cache name.
+     * @param fun An operation that accepts a cache entry and processes it.
+     * @param ignite Ignite.
+     * @param keysGen Keys generator.
+     * @param <K> Cache key object type.
+     * @param <V> Cache value object type.
+     */
+    public static <K, V> void update(String cacheName, Ignite ignite, IgniteConsumer<Cache.Entry<K, V>> fun,
+        IgniteSupplier<Set<K>> keysGen) {
+        bcast(cacheName, ignite, () -> {
+            Ignite ig = Ignition.localIgnite();
+            IgniteCache<K, V> cache = ig.getOrCreateCache(cacheName);
+
+            Affinity<K> affinity = ig.affinity(cacheName);
+            ClusterNode locNode = ig.cluster().localNode();
+
+            Collection<K> ks = affinity.mapKeysToNodes(keysGen.get()).get(locNode);
+
+            if (ks == null)
+                return;
+
+            Map<K, V> m = new ConcurrentHashMap<>();
+
+            for (K k : ks) {
+                V v = cache.localPeek(k);
+                fun.accept(new CacheEntryImpl<>(k, v));
+                m.put(k, v);
+            }
+
+            long before = System.currentTimeMillis();
+            cache.putAll(m);
+            System.out.println("PutAll took: " + (System.currentTimeMillis() - before));
+        });
+    }
+
+    /**
      * <b>Currently fold supports only commutative operations.<b/>
      *
      * @param cacheName Cache name.
@@ -463,11 +541,11 @@ public class CacheUtils {
      * @param folder Folder.
      * @param keyFilter Key filter.
      * @param accumulator Accumulator.
-     * @param zeroVal Zero value.
+     * @param zeroValSupp Zero value supplier.
      */
     public static <K, V, A> A distributedFold(String cacheName, IgniteBiFunction<Cache.Entry<K, V>, A, A> folder,
-        IgnitePredicate<K> keyFilter, BinaryOperator<A> accumulator, A zeroVal) {
-        return sparseFold(cacheName, folder, keyFilter, accumulator, zeroVal, null, null, 0,
+        IgnitePredicate<K> keyFilter, BinaryOperator<A> accumulator, IgniteSupplier<A> zeroValSupp) {
+        return sparseFold(cacheName, folder, keyFilter, accumulator, zeroValSupp, null, null, 0,
             false);
     }
 
@@ -478,17 +556,17 @@ public class CacheUtils {
      * @param folder Folder.
      * @param keyFilter Key filter.
      * @param accumulator Accumulator.
-     * @param zeroVal Zero value.
-     * @param defVal Def value.
-     * @param defKey Def key.
+     * @param zeroValSupp Zero value supplier.
+     * @param defVal Default value.
+     * @param defKey Default key.
      * @param defValCnt Def value count.
      * @param isNilpotent Is nilpotent.
      */
     private static <K, V, A> A sparseFold(String cacheName, IgniteBiFunction<Cache.Entry<K, V>, A, A> folder,
-        IgnitePredicate<K> keyFilter, BinaryOperator<A> accumulator, A zeroVal, V defVal, K defKey, long defValCnt,
-        boolean isNilpotent) {
+        IgnitePredicate<K> keyFilter, BinaryOperator<A> accumulator, IgniteSupplier<A> zeroValSupp, V defVal, K defKey,
+        long defValCnt, boolean isNilpotent) {
 
-        A defRes = zeroVal;
+        A defRes = zeroValSupp.get();
 
         if (!isNilpotent)
             for (int i = 0; i < defValCnt; i++)
@@ -504,7 +582,7 @@ public class CacheUtils {
             Affinity affinity = ignite.affinity(cacheName);
             ClusterNode locNode = ignite.cluster().localNode();
 
-            A a = zeroVal;
+            A a = zeroValSupp.get();
 
             // Iterate over all partitions. Some of them will be stored on that local node.
             for (int part = 0; part < partsCnt; part++) {
@@ -519,16 +597,54 @@ public class CacheUtils {
 
             return a;
         });
-        totalRes.add(defRes);
-        return totalRes.stream().reduce(zeroVal, accumulator);
+        return totalRes.stream().reduce(defRes, accumulator);
+    }
+
+    public static <K, V, A, W> A reduce(String cacheName, Ignite ignite,
+        IgniteTriFunction<W, Cache.Entry<K, V>, A, A> acc,
+        IgniteSupplier<W> supp,
+        IgniteSupplier<Iterable<Cache.Entry<K, V>>> entriesGen, IgniteBinaryOperator<A> comb,
+        IgniteSupplier<A> zeroValSupp) {
+
+        A defRes = zeroValSupp.get();
+
+        Collection<A> totalRes = bcast(cacheName, ignite, () -> {
+            // Use affinity in filter for ScanQuery. Otherwise we accept consumer in each node which is wrong.
+            A a = zeroValSupp.get();
+
+            W w = supp.get();
+
+            for (Cache.Entry<K, V> kvEntry : entriesGen.get())
+                a = acc.apply(w, kvEntry, a);
+
+            return a;
+        });
+
+        return totalRes.stream().reduce(defRes, comb);
+    }
+
+    public static <K, V, A, W> A reduce(String cacheName, IgniteTriFunction<W, Cache.Entry<K, V>, A, A> acc,
+        IgniteSupplier<W> supp,
+        IgniteSupplier<Iterable<Cache.Entry<K, V>>> entriesGen, IgniteBinaryOperator<A> comb,
+        IgniteSupplier<A> zeroValSupp) {
+        return reduce(cacheName, Ignition.localIgnite(), acc, supp, entriesGen, comb, zeroValSupp);
     }
 
     /**
      * @param cacheName Cache name.
      * @param run {@link Runnable} to broadcast to cache nodes for given cache name.
      */
+    public static void bcast(String cacheName, Ignite ignite, IgniteRunnable run) {
+        ignite.compute(ignite.cluster().forDataNodes(cacheName)).broadcast(run);
+    }
+
+    /**
+     * Broadcast runnable to data nodes of given cache.
+     * @param cacheName Cache name.
+     * @param run Runnable.
+     */
     public static void bcast(String cacheName, IgniteRunnable run) {
-        ignite().compute(ignite().cluster().forCacheNodes(cacheName)).broadcast(run);
+        bcast(cacheName, ignite(), run);
     }
 
     /**
@@ -537,6 +653,18 @@ public class CacheUtils {
      * @param <A> Type returned by the callable.
      */
     public static <A> Collection<A> bcast(String cacheName, IgniteCallable<A> call) {
-        return ignite().compute(ignite().cluster().forCacheNodes(cacheName)).broadcast(call);
+        return bcast(cacheName, ignite(), call);
+    }
+
+    /**
+     * Broadcast callable to data nodes of given cache.
+     * @param cacheName Cache name.
+     * @param ignite Ignite instance.
+     * @param call Callable to broadcast.
+     * @param <A> Type of callable result.
+     * @return Results of callable from each node.
+     */
+    public static <A> Collection<A> bcast(String cacheName, Ignite ignite, IgniteCallable<A> call) {
+        return ignite.compute(ignite.cluster().forDataNodes(cacheName)).broadcast(call);
     }
 }

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/keys/MatrixCacheKey.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/keys/MatrixCacheKey.java b/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/keys/MatrixCacheKey.java
index 669e9a4..0242560 100644
--- a/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/keys/MatrixCacheKey.java
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/keys/MatrixCacheKey.java
@@ -17,7 +17,7 @@
 
 package org.apache.ignite.ml.math.distributed.keys;
 
-import org.apache.ignite.lang.IgniteUuid;
+import java.util.UUID;
 
 /**
  * Base matrix cache key.
@@ -26,10 +26,10 @@ public interface MatrixCacheKey {
     /**
      * @return matrix id.
      */
-    public IgniteUuid matrixId();
+    public UUID matrixId();
 
     /**
      * @return affinity key.
      */
-    public IgniteUuid affinityKey();
+    public Object affinityKey();
 }

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/keys/impl/BlockMatrixKey.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/keys/impl/BlockMatrixKey.java b/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/keys/impl/BlockMatrixKey.java
index 2edd9cb..cc8c488 100644
--- a/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/keys/impl/BlockMatrixKey.java
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/keys/impl/BlockMatrixKey.java
@@ -21,6 +21,7 @@ import java.io.Externalizable;
 import java.io.IOException;
 import java.io.ObjectInput;
 import java.io.ObjectOutput;
+import java.util.UUID;
 import org.apache.ignite.binary.BinaryObjectException;
 import org.apache.ignite.binary.BinaryRawReader;
 import org.apache.ignite.binary.BinaryRawWriter;
@@ -47,7 +48,7 @@ public class BlockMatrixKey implements org.apache.ignite.ml.math.distributed.key
     /** Block col ID */
     private long blockIdCol;
     /** Matrix ID */
-    private IgniteUuid matrixUuid;
+    private UUID matrixUuid;
     /** Block affinity key. */
     private IgniteUuid affinityKey;
 
@@ -64,7 +65,7 @@ public class BlockMatrixKey implements org.apache.ignite.ml.math.distributed.key
      * @param matrixUuid Matrix uuid.
      * @param affinityKey Affinity key.
      */
-    public BlockMatrixKey(long rowId, long colId,  IgniteUuid matrixUuid, @Nullable IgniteUuid affinityKey) {
+    public BlockMatrixKey(long rowId, long colId,  UUID matrixUuid, @Nullable IgniteUuid affinityKey) {
         assert rowId >= 0;
         assert colId >= 0;
         assert matrixUuid != null;
@@ -86,7 +87,7 @@ public class BlockMatrixKey implements org.apache.ignite.ml.math.distributed.key
     }
 
     /** {@inheritDoc} */
-    @Override public IgniteUuid matrixId() {
+    @Override public UUID matrixId() {
         return matrixUuid;
     }
 
@@ -97,7 +98,7 @@ public class BlockMatrixKey implements org.apache.ignite.ml.math.distributed.key
 
     /** {@inheritDoc} */
     @Override public void writeExternal(ObjectOutput out) throws IOException {
-        U.writeGridUuid(out, matrixUuid);
+        out.writeObject(matrixUuid);
         U.writeGridUuid(out, affinityKey);
         out.writeLong(blockIdRow);
         out.writeLong(blockIdCol);
@@ -105,7 +106,7 @@ public class BlockMatrixKey implements org.apache.ignite.ml.math.distributed.key
 
     /** {@inheritDoc} */
     @Override public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
-        matrixUuid = U.readGridUuid(in);
+        matrixUuid = (UUID)in.readObject();
         affinityKey = U.readGridUuid(in);
         blockIdRow = in.readLong();
         blockIdCol = in.readLong();
@@ -115,7 +116,7 @@ public class BlockMatrixKey implements org.apache.ignite.ml.math.distributed.key
     @Override public void writeBinary(BinaryWriter writer) throws BinaryObjectException {
         BinaryRawWriter out = writer.rawWriter();
 
-        BinaryUtils.writeIgniteUuid(out, matrixUuid);
+        out.writeUuid(matrixUuid);
         BinaryUtils.writeIgniteUuid(out, affinityKey);
         out.writeLong(blockIdRow);
         out.writeLong(blockIdCol);
@@ -125,7 +126,7 @@ public class BlockMatrixKey implements org.apache.ignite.ml.math.distributed.key
     @Override public void readBinary(BinaryReader reader) throws BinaryObjectException {
         BinaryRawReader in = reader.rawReader();
 
-        matrixUuid = BinaryUtils.readIgniteUuid(in);
+        matrixUuid = in.readUuid();
         affinityKey = BinaryUtils.readIgniteUuid(in);
         blockIdRow = in.readLong();
         blockIdCol = in.readLong();
@@ -160,6 +161,4 @@ public class BlockMatrixKey implements org.apache.ignite.ml.math.distributed.key
     @Override public String toString() {
         return S.toString(BlockMatrixKey.class, this);
     }
-
-
 }

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/keys/impl/SparseMatrixKey.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/keys/impl/SparseMatrixKey.java b/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/keys/impl/SparseMatrixKey.java
index 0c34c8b..aa5e0ad 100644
--- a/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/keys/impl/SparseMatrixKey.java
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/math/distributed/keys/impl/SparseMatrixKey.java
@@ -21,30 +21,24 @@ import java.io.Externalizable;
 import java.io.IOException;
 import java.io.ObjectInput;
 import java.io.ObjectOutput;
-import org.apache.ignite.binary.BinaryObjectException;
-import org.apache.ignite.binary.BinaryRawReader;
-import org.apache.ignite.binary.BinaryRawWriter;
-import org.apache.ignite.binary.BinaryReader;
-import org.apache.ignite.binary.BinaryWriter;
-import org.apache.ignite.binary.Binarylizable;
-import org.apache.ignite.internal.binary.BinaryUtils;
+import java.util.UUID;
+import org.apache.ignite.cache.affinity.AffinityKeyMapped;
 import org.apache.ignite.internal.util.typedef.F;
 import org.apache.ignite.internal.util.typedef.internal.S;
-import org.apache.ignite.internal.util.typedef.internal.U;
-import org.apache.ignite.lang.IgniteUuid;
 import org.apache.ignite.ml.math.distributed.keys.RowColMatrixKey;
 import org.apache.ignite.ml.math.impls.matrix.SparseDistributedMatrix;
 
 /**
  * Key implementation for {@link SparseDistributedMatrix}.
  */
-public class SparseMatrixKey implements RowColMatrixKey, Externalizable, Binarylizable {
+public class SparseMatrixKey implements RowColMatrixKey, Externalizable {
     /** */
     private int idx;
     /** */
-    private IgniteUuid matrixId;
+    private UUID matrixId;
     /** */
-    private IgniteUuid affinityKey;
+    @AffinityKeyMapped
+    private Object affinityKey;
 
     /**
      * Default constructor (required by Externalizable).
@@ -56,7 +50,7 @@ public class SparseMatrixKey implements RowColMatrixKey, Externalizable, Binaryl
     /**
      * Build Key.
      */
-    public SparseMatrixKey(int idx, IgniteUuid matrixId, IgniteUuid affinityKey) {
+    public SparseMatrixKey(int idx, UUID matrixId, Object affinityKey) {
         assert idx >= 0 : "Index must be positive.";
         assert matrixId != null : "Matrix id can`t be null.";
 
@@ -71,54 +65,35 @@ public class SparseMatrixKey implements RowColMatrixKey, Externalizable, Binaryl
     }
 
     /** {@inheritDoc} */
-    @Override public IgniteUuid matrixId() {
+    @Override public UUID matrixId() {
         return matrixId;
     }
 
     /** {@inheritDoc} */
-    @Override public IgniteUuid affinityKey() {
+    @Override public Object affinityKey() {
         return affinityKey;
     }
 
     /** {@inheritDoc} */
     @Override public void writeExternal(ObjectOutput out) throws IOException {
-        U.writeGridUuid(out, matrixId);
-        U.writeGridUuid(out, affinityKey);
+//        U.writeGridUuid(out, matrixId);
+        out.writeObject(matrixId);
+        out.writeObject(affinityKey);
         out.writeInt(idx);
     }
 
     /** {@inheritDoc} */
     @Override public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
-        matrixId = U.readGridUuid(in);
-        affinityKey = U.readGridUuid(in);
-        idx = in.readInt();
-    }
-
-    /** {@inheritDoc} */
-    @Override public void writeBinary(BinaryWriter writer) throws BinaryObjectException {
-        BinaryRawWriter out = writer.rawWriter();
-
-        BinaryUtils.writeIgniteUuid(out, matrixId);
-        BinaryUtils.writeIgniteUuid(out, affinityKey);
-        out.writeInt(idx);
-    }
-
-    /** {@inheritDoc} */
-    @Override public void readBinary(BinaryReader reader) throws BinaryObjectException {
-        BinaryRawReader in = reader.rawReader();
-
-        matrixId = BinaryUtils.readIgniteUuid(in);
-        affinityKey = BinaryUtils.readIgniteUuid(in);
+        matrixId = (UUID)in.readObject();
+        affinityKey = in.readObject();
         idx = in.readInt();
     }
 
     /** {@inheritDoc} */
     @Override public int hashCode() {
-        int res = 1;
-
-        res += res * 37 + matrixId.hashCode();
-        res += res * 37 + idx;
-
+        int res = idx;
+        res = 31 * res + (matrixId != null ? matrixId.hashCode() : 0);
+        res = 31 * res + (affinityKey != null ? affinityKey.hashCode() : 0);
         return res;
     }
 

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/Functions.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/Functions.java b/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/Functions.java
index 022dd04..0b4ad12 100644
--- a/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/Functions.java
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/Functions.java
@@ -17,7 +17,9 @@
 
 package org.apache.ignite.ml.math.functions;
 
+import java.util.Comparator;
 import java.util.List;
+import java.util.function.BiFunction;
 import org.apache.ignite.lang.IgniteBiTuple;
 
 /**
@@ -75,6 +77,30 @@ public final class Functions {
     /** Function that returns {@code max(abs(a), abs(b))}. */
     public static final IgniteBiFunction<Double, Double, Double> MAX_ABS = (a, b) -> Math.max(Math.abs(a), Math.abs(b));
 
+    /**
+     * Generic 'max' function.
+     * @param a First object to compare.
+     * @param b Second object to compare.
+     * @param f Comparator.
+     * @param <T> Type of objects to compare.
+     * @return Maximum between {@code a} and {@code b} in terms of comparator {@code f}.
+     */
+    public static <T> T MAX_GENERIC(T a, T b, Comparator<T> f) {
+        return f.compare(a, b) > 0 ? a : b;
+    }
+
+    /**
+     * Generic 'min' function.
+     * @param a First object to compare.
+     * @param b Second object to compare.
+     * @param f Comparator.
+     * @param <T> Type of objects to compare.
+     * @return Minimum between {@code a} and {@code b} in terms of comparator {@code f}.
+     */
+    public static <T> T MIN_GENERIC(T a, T b, Comparator<T> f) {
+        return f.compare(a, b) > 0 ? a : b;
+    }
+
     /** Function that returns {@code min(abs(a), abs(b))}. */
     public static final IgniteBiFunction<Double, Double, Double> MIN_ABS = (a, b) -> Math.min(Math.abs(a), Math.abs(b));
 
@@ -185,4 +211,16 @@ public final class Functions {
                 return Math.pow(a, b);
         };
     }
+
+    /**
+     * Curry bifunction.
+     * @param f Bifunction to curry.
+     * @param <A> Type of first argument of {@code f}.
+     * @param <B> Type of second argument of {@code f}.
+     * @param <C> Return type of {@code f}.
+     * @return Curried bifunction.
+     */
+    public static <A, B, C> IgniteCurriedBiFunction<A, B, C> curry(BiFunction<A, B, C> f) {
+        return a -> b -> f.apply(a, b);
+    }
 }

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/IgniteBinaryOperator.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/IgniteBinaryOperator.java b/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/IgniteBinaryOperator.java
new file mode 100644
index 0000000..1170b67
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/IgniteBinaryOperator.java
@@ -0,0 +1,29 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.math.functions;
+
+import java.io.Serializable;
+import java.util.function.BinaryOperator;
+
+/**
+ * Serializable binary operator.
+ *
+ * @see java.util.function.BinaryOperator
+ */
+public interface IgniteBinaryOperator<A> extends BinaryOperator<A>, Serializable {
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/IgniteCurriedBiFunction.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/IgniteCurriedBiFunction.java b/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/IgniteCurriedBiFunction.java
new file mode 100644
index 0000000..3dd8490
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/IgniteCurriedBiFunction.java
@@ -0,0 +1,29 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.math.functions;
+
+import java.io.Serializable;
+import java.util.function.BiFunction;
+
+/**
+ * Serializable binary function.
+ *
+ * @see BiFunction
+ */
+public interface IgniteCurriedBiFunction<A, B, T> extends IgniteFunction<A, IgniteFunction<B, T>>, Serializable {
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/IgniteSupplier.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/IgniteSupplier.java b/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/IgniteSupplier.java
new file mode 100644
index 0000000..8c05b75
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/IgniteSupplier.java
@@ -0,0 +1,30 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.math.functions;
+
+import java.io.Serializable;
+import java.util.function.Supplier;
+
+/**
+ * Serializable supplier.
+ *
+ * @see java.util.function.Consumer
+ */
+@FunctionalInterface
+public interface IgniteSupplier<T> extends Supplier<T>, Serializable {
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/IgniteToDoubleFunction.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/IgniteToDoubleFunction.java b/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/IgniteToDoubleFunction.java
new file mode 100644
index 0000000..59a8bf3
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/math/functions/IgniteToDoubleFunction.java
@@ -0,0 +1,25 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.math.functions;
+
+import java.io.Serializable;
+import java.util.function.ToDoubleFunction;
+
+@FunctionalInterface
+public interface IgniteToDoubleFunction<T> extends ToDoubleFunction<T>, Serializable {
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/matrix/SparseBlockDistributedMatrix.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/matrix/SparseBlockDistributedMatrix.java b/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/matrix/SparseBlockDistributedMatrix.java
index 3d542bc..e829168 100644
--- a/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/matrix/SparseBlockDistributedMatrix.java
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/matrix/SparseBlockDistributedMatrix.java
@@ -20,13 +20,13 @@ package org.apache.ignite.ml.math.impls.matrix;
 import java.util.Collection;
 import java.util.List;
 import java.util.Map;
+import java.util.UUID;
 import org.apache.ignite.Ignite;
 import org.apache.ignite.IgniteCache;
 import org.apache.ignite.Ignition;
 import org.apache.ignite.cache.affinity.Affinity;
 import org.apache.ignite.cluster.ClusterNode;
 import org.apache.ignite.internal.util.lang.IgnitePair;
-import org.apache.ignite.lang.IgniteUuid;
 import org.apache.ignite.ml.math.Matrix;
 import org.apache.ignite.ml.math.StorageConstants;
 import org.apache.ignite.ml.math.Vector;
@@ -190,7 +190,7 @@ public class SparseBlockDistributedMatrix extends AbstractMatrix implements Stor
     }
 
     /** */
-    private IgniteUuid getUUID() {
+    private UUID getUUID() {
         return ((BlockMatrixStorage)getStorage()).getUUID();
     }
 

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/matrix/SparseDistributedMatrix.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/matrix/SparseDistributedMatrix.java b/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/matrix/SparseDistributedMatrix.java
index 9a18f8b..594aebc 100644
--- a/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/matrix/SparseDistributedMatrix.java
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/matrix/SparseDistributedMatrix.java
@@ -19,6 +19,7 @@ package org.apache.ignite.ml.math.impls.matrix;
 
 import java.util.Collection;
 import java.util.Map;
+import java.util.UUID;
 import org.apache.ignite.Ignite;
 import org.apache.ignite.IgniteCache;
 import org.apache.ignite.Ignition;
@@ -211,7 +212,7 @@ public class SparseDistributedMatrix extends AbstractMatrix implements StorageCo
     }
 
     /** */
-    public IgniteUuid getUUID() {
+    public UUID getUUID() {
         return ((SparseDistributedMatrixStorage)getStorage()).getUUID();
     }
 }

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/storage/matrix/BlockMatrixStorage.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/storage/matrix/BlockMatrixStorage.java b/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/storage/matrix/BlockMatrixStorage.java
index 0d5cf0a..cd76e5a 100644
--- a/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/storage/matrix/BlockMatrixStorage.java
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/storage/matrix/BlockMatrixStorage.java
@@ -24,6 +24,7 @@ import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Set;
+import java.util.UUID;
 import org.apache.ignite.IgniteCache;
 import org.apache.ignite.Ignition;
 import org.apache.ignite.cache.CacheAtomicityMode;
@@ -32,7 +33,6 @@ import org.apache.ignite.cache.CachePeekMode;
 import org.apache.ignite.cache.CacheWriteSynchronizationMode;
 import org.apache.ignite.configuration.CacheConfiguration;
 import org.apache.ignite.internal.util.lang.IgnitePair;
-import org.apache.ignite.internal.util.typedef.internal.U;
 import org.apache.ignite.lang.IgniteUuid;
 import org.apache.ignite.ml.math.MatrixStorage;
 import org.apache.ignite.ml.math.StorageConstants;
@@ -59,7 +59,7 @@ public class BlockMatrixStorage extends CacheUtils implements MatrixStorage, Sto
     /** Amount of columns in the matrix. */
     private int cols;
     /** Matrix uuid. */
-    private IgniteUuid uuid;
+    private UUID uuid;
     /** Block size about 8 KB of data. */
     private int maxBlockEdge = MAX_BLOCK_SIZE;
 
@@ -92,7 +92,7 @@ public class BlockMatrixStorage extends CacheUtils implements MatrixStorage, Sto
 
         cache = newCache();
 
-        uuid = IgniteUuid.randomUuid();
+        uuid = UUID.randomUUID();
     }
 
     /**
@@ -152,7 +152,7 @@ public class BlockMatrixStorage extends CacheUtils implements MatrixStorage, Sto
         out.writeInt(cols);
         out.writeInt(blocksInRow);
         out.writeInt(blocksInCol);
-        U.writeGridUuid(out, uuid);
+        out.writeObject(uuid);
         out.writeUTF(cache.getName());
     }
 
@@ -162,7 +162,7 @@ public class BlockMatrixStorage extends CacheUtils implements MatrixStorage, Sto
         cols = in.readInt();
         blocksInRow = in.readInt();
         blocksInCol = in.readInt();
-        uuid = U.readGridUuid(in);
+        uuid = (UUID)in.readObject();
         cache = ignite().getOrCreateCache(in.readUTF());
     }
 
@@ -201,7 +201,7 @@ public class BlockMatrixStorage extends CacheUtils implements MatrixStorage, Sto
      *
      * @return storage UUID.
      */
-    public IgniteUuid getUUID() {
+    public UUID getUUID() {
         return uuid;
     }
 

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/storage/matrix/SparseDistributedMatrixStorage.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/storage/matrix/SparseDistributedMatrixStorage.java b/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/storage/matrix/SparseDistributedMatrixStorage.java
index 95852b7..c40e73d 100644
--- a/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/storage/matrix/SparseDistributedMatrixStorage.java
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/math/impls/storage/matrix/SparseDistributedMatrixStorage.java
@@ -24,6 +24,7 @@ import java.io.ObjectInput;
 import java.io.ObjectOutput;
 import java.util.Map;
 import java.util.Set;
+import java.util.UUID;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 import org.apache.ignite.IgniteCache;
@@ -33,7 +34,6 @@ import org.apache.ignite.cache.CacheMode;
 import org.apache.ignite.cache.CachePeekMode;
 import org.apache.ignite.cache.CacheWriteSynchronizationMode;
 import org.apache.ignite.configuration.CacheConfiguration;
-import org.apache.ignite.lang.IgniteUuid;
 import org.apache.ignite.ml.math.MatrixStorage;
 import org.apache.ignite.ml.math.StorageConstants;
 import org.apache.ignite.ml.math.distributed.CacheUtils;
@@ -57,7 +57,7 @@ public class SparseDistributedMatrixStorage extends CacheUtils implements Matrix
     /** Random or sequential access mode. */
     private int acsMode;
     /** Matrix uuid. */
-    private IgniteUuid uuid;
+    private UUID uuid;
 
     /** Actual distributed storage. */
     private IgniteCache<
@@ -91,7 +91,7 @@ public class SparseDistributedMatrixStorage extends CacheUtils implements Matrix
 
         cache = newCache();
 
-        uuid = IgniteUuid.randomUuid();
+        uuid = UUID.randomUUID();
     }
 
     /**
@@ -115,6 +115,9 @@ public class SparseDistributedMatrixStorage extends CacheUtils implements Matrix
         // Cache is partitioned.
         cfg.setCacheMode(CacheMode.PARTITIONED);
 
+        // TODO: Possibly we should add a fix of https://issues.apache.org/jira/browse/IGNITE-6862 here commented below.
+        // cfg.setReadFromBackup(false);
+
         // Random cache name.
         cfg.setName(CACHE_NAME);
 
@@ -205,7 +208,7 @@ public class SparseDistributedMatrixStorage extends CacheUtils implements Matrix
 
     /** Build cache key for row/column. */
     public RowColMatrixKey getCacheKey(int idx) {
-        return new SparseMatrixKey(idx, uuid, null);
+        return new SparseMatrixKey(idx, uuid, idx);
     }
 
     /** {@inheritDoc} */
@@ -239,7 +242,7 @@ public class SparseDistributedMatrixStorage extends CacheUtils implements Matrix
         cols = in.readInt();
         acsMode = in.readInt();
         stoMode = in.readInt();
-        uuid = (IgniteUuid)in.readObject();
+        uuid = (UUID)in.readObject();
         cache = ignite().getOrCreateCache(in.readUTF());
     }
 
@@ -304,7 +307,7 @@ public class SparseDistributedMatrixStorage extends CacheUtils implements Matrix
     }
 
     /** */
-    public IgniteUuid getUUID() {
+    public UUID getUUID() {
         return uuid;
     }
 
@@ -312,7 +315,7 @@ public class SparseDistributedMatrixStorage extends CacheUtils implements Matrix
     @Override public Set<RowColMatrixKey> getAllKeys() {
         int range = stoMode == ROW_STORAGE_MODE ? rows : cols;
 
-        return IntStream.range(0, range).mapToObj(i -> new SparseMatrixKey(i, getUUID(), null)).collect(Collectors.toSet());
+        return IntStream.range(0, range).mapToObj(i -> new SparseMatrixKey(i, getUUID(), i)).collect(Collectors.toSet());
     }
 
     /** {@inheritDoc} */

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/structures/LabeledVector.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/structures/LabeledVector.java b/modules/ml/src/main/java/org/apache/ignite/ml/structures/LabeledVector.java
new file mode 100644
index 0000000..51b973a
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/structures/LabeledVector.java
@@ -0,0 +1,63 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.structures;
+
+import org.apache.ignite.ml.math.Vector;
+
+/**
+ * Class for vector with label.
+ *
+ * @param <V> Some class extending {@link Vector}.
+ * @param <T> Type of label.
+ */
+public class LabeledVector<V extends Vector, T> {
+    /** Vector. */
+    private final V vector;
+
+    /** Label. */
+    private final T lb;
+
+    /**
+     * Construct labeled vector.
+     *
+     * @param vector Vector.
+     * @param lb Label.
+     */
+    public LabeledVector(V vector, T lb) {
+        this.vector = vector;
+        this.lb = lb;
+    }
+
+    /**
+     * Get the vector.
+     *
+     * @return Vector.
+     */
+    public V vector() {
+        return vector;
+    }
+
+    /**
+     * Get the label.
+     *
+     * @return Label.
+     */
+    public T label() {
+        return lb;
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/structures/LabeledVectorDouble.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/structures/LabeledVectorDouble.java b/modules/ml/src/main/java/org/apache/ignite/ml/structures/LabeledVectorDouble.java
new file mode 100644
index 0000000..4ef9eae
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/structures/LabeledVectorDouble.java
@@ -0,0 +1,46 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.structures;
+
+import org.apache.ignite.ml.math.Vector;
+
+/**
+ * Labeled vector specialized to double label.
+ *
+ * @param <V> Type of vector.
+ */
+public class LabeledVectorDouble<V extends Vector> extends LabeledVector<V, Double> {
+    /**
+     * Construct LabeledVectorDouble.
+     *
+     * @param vector Vector.
+     * @param lb Label.
+     */
+    public LabeledVectorDouble(V vector, Double lb) {
+        super(vector, lb);
+    }
+
+    /**
+     * Get label as double.
+     *
+     * @return label as double.
+     */
+    public double doubleLabel() {
+        return label();
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/structures/package-info.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/structures/package-info.java b/modules/ml/src/main/java/org/apache/ignite/ml/structures/package-info.java
new file mode 100644
index 0000000..ec9d79e
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/structures/package-info.java
@@ -0,0 +1,22 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * <!-- Package description. -->
+ * Contains some utility structures.
+ */
+package org.apache.ignite.ml.structures;
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/CategoricalRegionInfo.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/CategoricalRegionInfo.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/CategoricalRegionInfo.java
new file mode 100644
index 0000000..3ae474e
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/CategoricalRegionInfo.java
@@ -0,0 +1,72 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees;
+
+import java.io.Externalizable;
+import java.io.IOException;
+import java.io.ObjectInput;
+import java.io.ObjectOutput;
+import java.util.BitSet;
+
+/**
+ * Information about categorical region.
+ */
+public class CategoricalRegionInfo extends RegionInfo implements Externalizable {
+    /**
+     * Bitset representing categories of this region.
+     */
+    private BitSet cats;
+
+    /**
+     * @param impurity Impurity of region.
+     * @param cats Bitset representing categories of this region.
+     */
+    public CategoricalRegionInfo(double impurity, BitSet cats) {
+        super(impurity);
+
+        this.cats = cats;
+    }
+
+    /**
+     * No-op constructor for serialization/deserialization.
+     */
+    public CategoricalRegionInfo() {
+        // No-op
+    }
+
+    /**
+     * Get bitset representing categories of this region.
+     *
+     * @return Bitset representing categories of this region.
+     */
+    public BitSet cats() {
+        return cats;
+    }
+
+    /** {@inheritDoc} */
+    @Override public void writeExternal(ObjectOutput out) throws IOException {
+        super.writeExternal(out);
+        out.writeObject(cats);
+    }
+
+    /** {@inheritDoc} */
+    @Override public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
+        super.readExternal(in);
+        cats = (BitSet)in.readObject();
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/CategoricalSplitInfo.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/CategoricalSplitInfo.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/CategoricalSplitInfo.java
new file mode 100644
index 0000000..94cb1e8
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/CategoricalSplitInfo.java
@@ -0,0 +1,68 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees;
+
+import java.util.BitSet;
+import org.apache.ignite.ml.trees.nodes.CategoricalSplitNode;
+import org.apache.ignite.ml.trees.nodes.SplitNode;
+import org.apache.ignite.ml.trees.trainers.columnbased.vectors.SplitInfo;
+
+/**
+ * Information about split of categorical feature.
+ *
+ * @param <D> Class representing information of left and right subregions.
+ */
+public class CategoricalSplitInfo<D extends RegionInfo> extends SplitInfo<D> {
+    /** Bitset indicating which vectors are assigned to left subregion. */
+    private final BitSet bs;
+
+    /**
+     * @param regionIdx Index of region which is split.
+     * @param leftData Data of left subregion.
+     * @param rightData Data of right subregion.
+     * @param bs Bitset indicating which vectors are assigned to left subregion.
+     */
+    public CategoricalSplitInfo(int regionIdx, D leftData, D rightData,
+        BitSet bs) {
+        super(regionIdx, leftData, rightData);
+        this.bs = bs;
+    }
+
+    /** {@inheritDoc} */
+    @Override public SplitNode createSplitNode(int featureIdx) {
+        return new CategoricalSplitNode(featureIdx, bs);
+    }
+
+    /**
+     * Get bitset indicating which vectors are assigned to left subregion.
+     */
+    public BitSet bitSet() {
+        return bs;
+    }
+
+    /** {@inheritDoc} */
+    @Override public String toString() {
+        return "CategoricalSplitInfo [" +
+            "infoGain=" + infoGain +
+            ", regionIdx=" + regionIdx +
+            ", leftData=" + leftData +
+            ", bs=" + bs +
+            ", rightData=" + rightData +
+            ']';
+    }
+}


[2/4] ignite git commit: IGNITE-5218: First version of decision trees. This closes #2936

Posted by is...@apache.org.
http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/caches/FeaturesCache.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/caches/FeaturesCache.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/caches/FeaturesCache.java
new file mode 100644
index 0000000..fcc1f16
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/caches/FeaturesCache.java
@@ -0,0 +1,151 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased.caches;
+
+import java.util.Set;
+import java.util.UUID;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.cache.CacheAtomicityMode;
+import org.apache.ignite.cache.CacheMode;
+import org.apache.ignite.cache.CacheWriteSynchronizationMode;
+import org.apache.ignite.cache.affinity.AffinityKeyMapped;
+import org.apache.ignite.configuration.CacheConfiguration;
+import org.apache.ignite.ml.math.functions.IgniteBiFunction;
+import org.apache.ignite.ml.trees.trainers.columnbased.ColumnDecisionTreeTrainer;
+
+/**
+ * Cache storing features for {@link ColumnDecisionTreeTrainer}.
+ */
+public class FeaturesCache {
+    /**
+     * Name of cache which is used for storing features for {@link ColumnDecisionTreeTrainer}.
+     */
+    public static final String COLUMN_DECISION_TREE_TRAINER_FEATURES_CACHE_NAME = "COLUMN_DECISION_TREE_TRAINER_FEATURES_CACHE_NAME";
+
+    /**
+     * Key of features cache.
+     */
+    public static class FeatureKey {
+        /** Column key of cache used as input for {@link ColumnDecisionTreeTrainer}. */
+        @AffinityKeyMapped
+        private Object parentColKey;
+
+        /** Index of feature. */
+        private final int featureIdx;
+
+        /** UUID of training. */
+        private final UUID trainingUUID;
+
+        /**
+         * Construct FeatureKey.
+         *
+         * @param featureIdx Feature index.
+         * @param trainingUUID UUID of training.
+         * @param parentColKey Column key of cache used as input.
+         */
+        public FeatureKey(int featureIdx, UUID trainingUUID, Object parentColKey) {
+            this.parentColKey = parentColKey;
+            this.featureIdx = featureIdx;
+            this.trainingUUID = trainingUUID;
+            this.parentColKey = parentColKey;
+        }
+
+        /** {@inheritDoc} */
+        @Override public boolean equals(Object o) {
+            if (this == o)
+                return true;
+            if (o == null || getClass() != o.getClass())
+                return false;
+
+            FeatureKey key = (FeatureKey)o;
+
+            if (featureIdx != key.featureIdx)
+                return false;
+            return trainingUUID != null ? trainingUUID.equals(key.trainingUUID) : key.trainingUUID == null;
+        }
+
+        /** {@inheritDoc} */
+        @Override public int hashCode() {
+            int res = trainingUUID != null ? trainingUUID.hashCode() : 0;
+            res = 31 * res + featureIdx;
+            return res;
+        }
+    }
+
+    /**
+     * Create new projections cache for ColumnDecisionTreeTrainer if needed.
+     *
+     * @param ignite Ignite instance.
+     */
+    public static IgniteCache<FeatureKey, double[]> getOrCreate(Ignite ignite) {
+        CacheConfiguration<FeatureKey, double[]> cfg = new CacheConfiguration<>();
+
+        // Write to primary.
+        cfg.setWriteSynchronizationMode(CacheWriteSynchronizationMode.PRIMARY_SYNC);
+
+        // Atomic transactions only.
+        cfg.setAtomicityMode(CacheAtomicityMode.ATOMIC);
+
+        // No eviction.
+        cfg.setEvictionPolicy(null);
+
+        // No copying of values.
+        cfg.setCopyOnRead(false);
+
+        // Cache is partitioned.
+        cfg.setCacheMode(CacheMode.PARTITIONED);
+
+        cfg.setOnheapCacheEnabled(true);
+
+        cfg.setBackups(0);
+
+        cfg.setName(COLUMN_DECISION_TREE_TRAINER_FEATURES_CACHE_NAME);
+
+        return ignite.getOrCreateCache(cfg);
+    }
+
+    /**
+     * Construct FeatureKey from index, uuid and affinity key.
+     *
+     * @param idx Feature index.
+     * @param uuid UUID of training.
+     * @param aff Affinity key.
+     * @return FeatureKey.
+     */
+    public static FeatureKey getFeatureCacheKey(int idx, UUID uuid, Object aff) {
+        return new FeatureKey(idx, uuid, aff);
+    }
+
+    /**
+     * Clear all data from features cache related to given training.
+     *
+     * @param featuresCnt Count of features.
+     * @param affinity Affinity function.
+     * @param uuid Training uuid.
+     * @param ignite Ignite instance.
+     */
+    public static void clear(int featuresCnt, IgniteBiFunction<Integer, Ignite, Object> affinity, UUID uuid,
+        Ignite ignite) {
+        Set<FeatureKey> toRmv = IntStream.range(0, featuresCnt).boxed().map(fIdx -> getFeatureCacheKey(fIdx, uuid, affinity.apply(fIdx, ignite))).collect(Collectors.toSet());
+
+        getOrCreate(ignite).removeAll(toRmv);
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/caches/ProjectionsCache.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/caches/ProjectionsCache.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/caches/ProjectionsCache.java
new file mode 100644
index 0000000..29cf6b4
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/caches/ProjectionsCache.java
@@ -0,0 +1,284 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased.caches;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.PrimitiveIterator;
+import java.util.Set;
+import java.util.UUID;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.Ignition;
+import org.apache.ignite.cache.CacheAtomicityMode;
+import org.apache.ignite.cache.CacheMode;
+import org.apache.ignite.cache.CacheWriteSynchronizationMode;
+import org.apache.ignite.cache.affinity.Affinity;
+import org.apache.ignite.cache.affinity.AffinityKeyMapped;
+import org.apache.ignite.configuration.CacheConfiguration;
+import org.apache.ignite.lang.IgniteBiTuple;
+import org.apache.ignite.ml.math.functions.IgniteBiFunction;
+import org.apache.ignite.ml.math.functions.IgniteFunction;
+import org.apache.ignite.ml.trees.trainers.columnbased.ColumnDecisionTreeTrainer;
+import org.apache.ignite.ml.trees.trainers.columnbased.RegionProjection;
+
+/**
+ * Cache used for storing data of region projections on features.
+ */
+public class ProjectionsCache {
+    /**
+     * Name of cache which is used for storing data of region projections on features of {@link
+     * ColumnDecisionTreeTrainer}.
+     */
+    public static final String CACHE_NAME = "COLUMN_DECISION_TREE_TRAINER_PROJECTIONS_CACHE_NAME";
+
+    /**
+     * Key of region projections cache.
+     */
+    public static class RegionKey {
+        /** Column key of cache used as input for {@link ColumnDecisionTreeTrainer}. */
+        @AffinityKeyMapped
+        private final Object parentColKey;
+
+        /** Feature index. */
+        private final int featureIdx;
+
+        /** Region index. */
+        private final int regBlockIdx;
+
+        /** Training UUID. */
+        private final UUID trainingUUID;
+
+        /**
+         * Construct a RegionKey from feature index, index of block, key of column in input cache and UUID of training.
+         *
+         * @param featureIdx Feature index.
+         * @param regBlockIdx Index of block.
+         * @param parentColKey Key of column in input cache.
+         * @param trainingUUID UUID of training.
+         */
+        public RegionKey(int featureIdx, int regBlockIdx, Object parentColKey, UUID trainingUUID) {
+            this.featureIdx = featureIdx;
+            this.regBlockIdx = regBlockIdx;
+            this.trainingUUID = trainingUUID;
+            this.parentColKey = parentColKey;
+        }
+
+        /**
+         * Feature index.
+         *
+         * @return Feature index.
+         */
+        public int featureIdx() {
+            return featureIdx;
+        }
+
+        /**
+         * Region block index.
+         *
+         * @return Region block index.
+         */
+        public int regionBlockIndex() {
+            return regBlockIdx;
+        }
+
+        /**
+         * UUID of training.
+         *
+         * @return UUID of training.
+         */
+        public UUID trainingUUID() {
+            return trainingUUID;
+        }
+
+        /** {@inheritDoc} */
+        @Override public boolean equals(Object o) {
+            if (this == o)
+                return true;
+            if (o == null || getClass() != o.getClass())
+                return false;
+
+            RegionKey key = (RegionKey)o;
+
+            if (featureIdx != key.featureIdx)
+                return false;
+            if (regBlockIdx != key.regBlockIdx)
+                return false;
+            return trainingUUID != null ? trainingUUID.equals(key.trainingUUID) : key.trainingUUID == null;
+        }
+
+        /** {@inheritDoc} */
+        @Override public int hashCode() {
+            int res = trainingUUID != null ? trainingUUID.hashCode() : 0;
+            res = 31 * res + featureIdx;
+            res = 31 * res + regBlockIdx;
+            return res;
+        }
+
+        /** {@inheritDoc} */
+        @Override public String toString() {
+            return "RegionKey [" +
+                "parentColKey=" + parentColKey +
+                ", featureIdx=" + featureIdx +
+                ", regBlockIdx=" + regBlockIdx +
+                ", trainingUUID=" + trainingUUID +
+                ']';
+        }
+    }
+
+    /**
+     * Affinity service for region projections cache.
+     *
+     * @return Affinity service for region projections cache.
+     */
+    public static Affinity<RegionKey> affinity() {
+        return Ignition.localIgnite().affinity(CACHE_NAME);
+    }
+
+    /**
+     * Get or create region projections cache.
+     *
+     * @param ignite Ignite instance.
+     * @return Region projections cache.
+     */
+    public static IgniteCache<RegionKey, List<RegionProjection>> getOrCreate(Ignite ignite) {
+        CacheConfiguration<RegionKey, List<RegionProjection>> cfg = new CacheConfiguration<>();
+
+        // Write to primary.
+        cfg.setWriteSynchronizationMode(CacheWriteSynchronizationMode.PRIMARY_SYNC);
+
+        // Atomic transactions only.
+        cfg.setAtomicityMode(CacheAtomicityMode.ATOMIC);
+
+        // No eviction.
+        cfg.setEvictionPolicy(null);
+
+        // No copying of values.
+        cfg.setCopyOnRead(false);
+
+        // Cache is partitioned.
+        cfg.setCacheMode(CacheMode.PARTITIONED);
+
+        cfg.setBackups(0);
+
+        cfg.setOnheapCacheEnabled(true);
+
+        cfg.setName(CACHE_NAME);
+
+        return ignite.getOrCreateCache(cfg);
+    }
+
+    /**
+     * Get region projections in the form of map (regionIndex -> regionProjections).
+     *
+     * @param featureIdx Feature index.
+     * @param maxDepth Max depth of decision tree.
+     * @param regionIndexes Indexes of regions for which we want get projections.
+     * @param blockSize Size of regions block.
+     * @param affinity Affinity function.
+     * @param trainingUUID UUID of training.
+     * @param ignite Ignite instance.
+     * @return Region projections in the form of map (regionIndex -> regionProjections).
+     */
+    public static Map<Integer, RegionProjection> projectionsOfRegions(int featureIdx, int maxDepth,
+        IntStream regionIndexes, int blockSize, IgniteFunction<Integer, Object> affinity, UUID trainingUUID,
+        Ignite ignite) {
+        HashMap<Integer, RegionProjection> regsForSearch = new HashMap<>();
+        IgniteCache<RegionKey, List<RegionProjection>> cache = getOrCreate(ignite);
+
+        PrimitiveIterator.OfInt itr = regionIndexes.iterator();
+
+        int curBlockIdx = -1;
+        List<RegionProjection> block = null;
+
+        Object affinityKey = affinity.apply(featureIdx);
+
+        while (itr.hasNext()) {
+            int i = itr.nextInt();
+
+            int blockIdx = i / blockSize;
+
+            if (blockIdx != curBlockIdx) {
+                block = cache.localPeek(key(featureIdx, blockIdx, affinityKey, trainingUUID));
+                curBlockIdx = blockIdx;
+            }
+
+            if (block == null)
+                throw new IllegalStateException("Unexpected null block at index " + i);
+
+            RegionProjection reg = block.get(i % blockSize);
+
+            if (reg.depth() < maxDepth)
+                regsForSearch.put(i, reg);
+        }
+
+        return regsForSearch;
+    }
+
+    /**
+     * Returns projections of regions on given feature filtered by maximal depth in the form of (region index -> region projection).
+     *
+     * @param featureIdx Feature index.
+     * @param maxDepth Maximal depth of the tree.
+     * @param regsCnt Count of regions.
+     * @param blockSize Size of regions blocks.
+     * @param affinity Affinity function.
+     * @param trainingUUID UUID of training.
+     * @param ignite Ignite instance.
+     * @return Projections of regions on given feature filtered by maximal depth in the form of (region index -> region projection).
+     */
+    public static Map<Integer, RegionProjection> projectionsOfFeature(int featureIdx, int maxDepth, int regsCnt,
+        int blockSize, IgniteFunction<Integer, Object> affinity, UUID trainingUUID, Ignite ignite) {
+        return projectionsOfRegions(featureIdx, maxDepth, IntStream.range(0, regsCnt), blockSize, affinity, trainingUUID, ignite);
+    }
+
+    /**
+     * Construct key for projections cache.
+     *
+     * @param featureIdx Feature index.
+     * @param regBlockIdx Region block index.
+     * @param parentColKey Column key of cache used as input for {@link ColumnDecisionTreeTrainer}.
+     * @param uuid UUID of training.
+     * @return Key for projections cache.
+     */
+    public static RegionKey key(int featureIdx, int regBlockIdx, Object parentColKey, UUID uuid) {
+        return new RegionKey(featureIdx, regBlockIdx, parentColKey, uuid);
+    }
+
+    /**
+     * Clear data from projections cache related to given training.
+     *
+     * @param featuresCnt Features count.
+     * @param regs Regions count.
+     * @param aff Affinity function.
+     * @param uuid UUID of training.
+     * @param ignite Ignite instance.
+     */
+    public static void clear(int featuresCnt, int regs, IgniteBiFunction<Integer, Ignite, Object> aff, UUID uuid,
+        Ignite ignite) {
+        Set<RegionKey> toRmv = IntStream.range(0, featuresCnt).boxed().
+            flatMap(fIdx -> IntStream.range(0, regs).boxed().map(reg -> new IgniteBiTuple<>(fIdx, reg))).
+            map(t -> key(t.get1(), t.get2(), aff.apply(t.get1(), ignite), uuid)).
+            collect(Collectors.toSet());
+
+        getOrCreate(ignite).removeAll(toRmv);
+    }
+}
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/caches/SplitCache.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/caches/SplitCache.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/caches/SplitCache.java
new file mode 100644
index 0000000..ecbc861
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/caches/SplitCache.java
@@ -0,0 +1,206 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased.caches;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Set;
+import java.util.UUID;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import java.util.stream.IntStream;
+import javax.cache.Cache;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.Ignition;
+import org.apache.ignite.cache.CacheAtomicityMode;
+import org.apache.ignite.cache.CacheMode;
+import org.apache.ignite.cache.CacheWriteSynchronizationMode;
+import org.apache.ignite.cache.affinity.Affinity;
+import org.apache.ignite.cache.affinity.AffinityKeyMapped;
+import org.apache.ignite.configuration.CacheConfiguration;
+import org.apache.ignite.internal.processors.cache.CacheEntryImpl;
+import org.apache.ignite.lang.IgniteBiTuple;
+import org.apache.ignite.ml.math.functions.IgniteBiFunction;
+import org.apache.ignite.ml.trees.trainers.columnbased.ColumnDecisionTreeTrainer;
+
+/**
+ * Class for working with cache used for storing of best splits during training with {@link ColumnDecisionTreeTrainer}.
+ */
+public class SplitCache {
+    /** Name of splits cache. */
+    public static final String CACHE_NAME = "COLUMN_DECISION_TREE_TRAINER_SPLIT_CACHE_NAME";
+
+    /**
+     * Class used for keys in the splits cache.
+     */
+    public static class SplitKey {
+        /** UUID of current training. */
+        private final UUID trainingUUID;
+
+        /** Affinity key of input data. */
+        @AffinityKeyMapped
+        private final Object parentColKey;
+
+        /** Index of feature by which the split is made. */
+        private final int featureIdx;
+
+        /**
+         * Construct SplitKey.
+         *
+         * @param trainingUUID UUID of the training.
+         * @param parentColKey Affinity key used to ensure that cache entry for given feature will be on the same node
+         * as column with that feature in input.
+         * @param featureIdx Feature index.
+         */
+        public SplitKey(UUID trainingUUID, Object parentColKey, int featureIdx) {
+            this.trainingUUID = trainingUUID;
+            this.featureIdx = featureIdx;
+            this.parentColKey = parentColKey;
+        }
+
+        /** Get UUID of current training. */
+        public UUID trainingUUID() {
+            return trainingUUID;
+        }
+
+        /**
+         * Get feature index.
+         *
+         * @return Feature index.
+         */
+        public int featureIdx() {
+            return featureIdx;
+        }
+
+        /** {@inheritDoc} */
+        @Override public boolean equals(Object o) {
+            if (this == o)
+                return true;
+            if (o == null || getClass() != o.getClass())
+                return false;
+
+            SplitKey splitKey = (SplitKey)o;
+
+            if (featureIdx != splitKey.featureIdx)
+                return false;
+            return trainingUUID != null ? trainingUUID.equals(splitKey.trainingUUID) : splitKey.trainingUUID == null;
+
+        }
+
+        /** {@inheritDoc} */
+        @Override public int hashCode() {
+            int res = trainingUUID != null ? trainingUUID.hashCode() : 0;
+            res = 31 * res + featureIdx;
+            return res;
+        }
+    }
+
+    /**
+     * Construct the key for splits cache.
+     *
+     * @param featureIdx Feature index.
+     * @param parentColKey Affinity key used to ensure that cache entry for given feature will be on the same node as
+     * column with that feature in input.
+     * @param uuid UUID of current training.
+     * @return Key for splits cache.
+     */
+    public static SplitKey key(int featureIdx, Object parentColKey, UUID uuid) {
+        return new SplitKey(uuid, parentColKey, featureIdx);
+    }
+
+    /**
+     * Get or create splits cache.
+     *
+     * @param ignite Ignite instance.
+     * @return Splits cache.
+     */
+    public static IgniteCache<SplitKey, IgniteBiTuple<Integer, Double>> getOrCreate(Ignite ignite) {
+        CacheConfiguration<SplitKey, IgniteBiTuple<Integer, Double>> cfg = new CacheConfiguration<>();
+
+        // Write to primary.
+        cfg.setWriteSynchronizationMode(CacheWriteSynchronizationMode.PRIMARY_SYNC);
+
+        // Atomic transactions only.
+        cfg.setAtomicityMode(CacheAtomicityMode.ATOMIC);
+
+        // No eviction.
+        cfg.setEvictionPolicy(null);
+
+        // No copying of values.
+        cfg.setCopyOnRead(false);
+
+        // Cache is partitioned.
+        cfg.setCacheMode(CacheMode.PARTITIONED);
+
+        cfg.setBackups(0);
+
+        cfg.setOnheapCacheEnabled(true);
+
+        cfg.setName(CACHE_NAME);
+
+        return ignite.getOrCreateCache(cfg);
+    }
+
+    /**
+     * Affinity function used in splits cache.
+     *
+     * @return Affinity function used in splits cache.
+     */
+    public static Affinity<SplitKey> affinity() {
+        return Ignition.localIgnite().affinity(CACHE_NAME);
+    }
+
+    /**
+     * Returns local entries for keys corresponding to {@code featureIndexes}.
+     *
+     * @param featureIndexes Index of features.
+     * @param affinity Affinity function.
+     * @param trainingUUID UUID of training.
+     * @return local entries for keys corresponding to {@code featureIndexes}.
+     */
+    public static Iterable<Cache.Entry<SplitKey, IgniteBiTuple<Integer, Double>>> localEntries(
+        Set<Integer> featureIndexes,
+        IgniteBiFunction<Integer, Ignite, Object> affinity,
+        UUID trainingUUID) {
+        Ignite ignite = Ignition.localIgnite();
+        Set<SplitKey> keys = featureIndexes.stream().map(fIdx -> new SplitKey(trainingUUID, affinity.apply(fIdx, ignite), fIdx)).collect(Collectors.toSet());
+
+        Collection<SplitKey> locKeys = affinity().mapKeysToNodes(keys).getOrDefault(ignite.cluster().localNode(), Collections.emptyList());
+
+        return () -> {
+            Function<SplitKey, Cache.Entry<SplitKey, IgniteBiTuple<Integer, Double>>> f = k -> (new CacheEntryImpl<>(k, getOrCreate(ignite).localPeek(k)));
+            return locKeys.stream().map(f).iterator();
+        };
+    }
+
+    /**
+     * Clears data related to current training from splits cache related to given training.
+     *
+     * @param featuresCnt Count of features.
+     * @param affinity Affinity function.
+     * @param uuid UUID of the given training.
+     * @param ignite Ignite instance.
+     */
+    public static void clear(int featuresCnt, IgniteBiFunction<Integer, Ignite, Object> affinity, UUID uuid,
+        Ignite ignite) {
+        Set<SplitKey> toRmv = IntStream.range(0, featuresCnt).boxed().map(fIdx -> new SplitKey(uuid, affinity.apply(fIdx, ignite), fIdx)).collect(Collectors.toSet());
+
+        getOrCreate(ignite).removeAll(toRmv);
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/contsplitcalcs/ContinuousSplitCalculators.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/contsplitcalcs/ContinuousSplitCalculators.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/contsplitcalcs/ContinuousSplitCalculators.java
new file mode 100644
index 0000000..9fd4c66
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/contsplitcalcs/ContinuousSplitCalculators.java
@@ -0,0 +1,34 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased.contsplitcalcs;
+
+import org.apache.ignite.Ignite;
+import org.apache.ignite.ml.math.functions.IgniteCurriedBiFunction;
+import org.apache.ignite.ml.math.functions.IgniteFunction;
+import org.apache.ignite.ml.trees.trainers.columnbased.ColumnDecisionTreeTrainerInput;
+
+/** Continuous Split Calculators. */
+public class ContinuousSplitCalculators {
+    /** Variance split calculator. */
+    public static IgniteFunction<ColumnDecisionTreeTrainerInput, VarianceSplitCalculator> VARIANCE = input ->
+        new VarianceSplitCalculator();
+
+    /** Gini split calculator. */
+    public static IgniteCurriedBiFunction<Ignite, ColumnDecisionTreeTrainerInput, GiniSplitCalculator> GINI = ignite ->
+        input -> new GiniSplitCalculator(input.labels(ignite));
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/contsplitcalcs/GiniSplitCalculator.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/contsplitcalcs/GiniSplitCalculator.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/contsplitcalcs/GiniSplitCalculator.java
new file mode 100644
index 0000000..259c84c
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/contsplitcalcs/GiniSplitCalculator.java
@@ -0,0 +1,234 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased.contsplitcalcs;
+
+import it.unimi.dsi.fastutil.doubles.Double2IntArrayMap;
+import java.io.IOException;
+import java.io.ObjectInput;
+import java.io.ObjectOutput;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.PrimitiveIterator;
+import java.util.stream.DoubleStream;
+import org.apache.ignite.ml.trees.ContinuousRegionInfo;
+import org.apache.ignite.ml.trees.ContinuousSplitCalculator;
+import org.apache.ignite.ml.trees.trainers.columnbased.vectors.ContinuousSplitInfo;
+import org.apache.ignite.ml.trees.trainers.columnbased.vectors.SplitInfo;
+
+/**
+ * Calculator for Gini impurity.
+ */
+public class GiniSplitCalculator implements ContinuousSplitCalculator<GiniSplitCalculator.GiniData> {
+    /** Mapping assigning index to each member value */
+    private final Map<Double, Integer> mapping = new Double2IntArrayMap();
+
+    /**
+     * Create Gini split calculator from labels.
+     *
+     * @param labels Labels.
+     */
+    public GiniSplitCalculator(double[] labels) {
+        int i = 0;
+
+        for (double label : labels) {
+            if (!mapping.containsKey(label)) {
+                mapping.put(label, i);
+                i++;
+            }
+        }
+    }
+
+    /** {@inheritDoc} */
+    @Override public GiniData calculateRegionInfo(DoubleStream s, int l) {
+        PrimitiveIterator.OfDouble itr = s.iterator();
+
+        Map<Double, Integer> m = new HashMap<>();
+
+        int size = 0;
+
+        while (itr.hasNext()) {
+            size++;
+            m.compute(itr.next(), (a, i) -> i != null ? i + 1 : 1);
+        }
+
+        double c2 = m.values().stream().mapToDouble(v -> v * v).sum();
+
+        int[] cnts = new int[mapping.size()];
+
+        m.forEach((key, value) -> cnts[mapping.get(key)] = value);
+
+        return new GiniData(size != 0 ? 1 - c2 / (size * size) : 0.0, size, cnts, c2);
+    }
+
+    /** {@inheritDoc} */
+    @Override public SplitInfo<GiniData> splitRegion(Integer[] s, double[] values, double[] labels, int regionIdx,
+        GiniData d) {
+        int size = d.getSize();
+
+        double lg = 0.0;
+        double rg = d.impurity();
+
+        double lc2 = 0.0;
+        double rc2 = d.c2;
+        int lSize = 0;
+
+        double minImpurity = d.impurity() * size;
+        double curThreshold;
+        double curImpurity;
+        double threshold = Double.NEGATIVE_INFINITY;
+
+        int i = 0;
+        int nextIdx = s[0];
+        i++;
+        double[] lrImps = new double[] {0.0, d.impurity(), lc2, rc2};
+
+        int[] lMapCur = new int[d.counts().length];
+        int[] rMapCur = new int[d.counts().length];
+
+        System.arraycopy(d.counts(), 0, rMapCur, 0, d.counts().length);
+
+        int[] lMap = new int[d.counts().length];
+        int[] rMap = new int[d.counts().length];
+
+        System.arraycopy(d.counts(), 0, rMap, 0, d.counts().length);
+
+        do {
+            // Process all values equal to prev.
+            while (i < s.length) {
+                moveLeft(labels[nextIdx], i, size - i, lMapCur, rMapCur, lrImps);
+                curImpurity = (i * lrImps[0] + (size - i) * lrImps[1]);
+                curThreshold = values[nextIdx];
+
+                if (values[nextIdx] != values[(nextIdx = s[i++])]) {
+                    if (curImpurity < minImpurity) {
+                        lSize = i - 1;
+
+                        lg = lrImps[0];
+                        rg = lrImps[1];
+
+                        lc2 = lrImps[2];
+                        rc2 = lrImps[3];
+
+                        System.arraycopy(lMapCur, 0, lMap, 0, lMapCur.length);
+                        System.arraycopy(rMapCur, 0, rMap, 0, rMapCur.length);
+
+                        minImpurity = curImpurity;
+                        threshold = curThreshold;
+                    }
+
+                    break;
+                }
+            }
+        }
+        while (i < s.length - 1);
+
+        if (lSize == size || lSize == 0)
+            return null;
+
+        GiniData lData = new GiniData(lg, lSize, lMap, lc2);
+        int rSize = size - lSize;
+        GiniData rData = new GiniData(rg, rSize, rMap, rc2);
+
+        return new ContinuousSplitInfo<>(regionIdx, threshold, lData, rData);
+    }
+
+    /**
+     * Add point to the left interval and remove it from the right interval and calculate necessary statistics on
+     * intervals with new bounds.
+     */
+    private void moveLeft(double x, int lSize, int rSize, int[] lMap, int[] rMap, double[] data) {
+        double lc2 = data[2];
+        double rc2 = data[3];
+
+        Integer idx = mapping.get(x);
+
+        int cxl = lMap[idx];
+        int cxr = rMap[idx];
+
+        lc2 += 2 * cxl + 1;
+        rc2 -= 2 * cxr - 1;
+
+        lMap[idx] += 1;
+        rMap[idx] -= 1;
+
+        data[0] = 1 - lc2 / (lSize * lSize);
+        data[1] = 1 - rc2 / (rSize * rSize);
+
+        data[2] = lc2;
+        data[3] = rc2;
+    }
+
+    /**
+     * Data used for gini impurity calculations.
+     */
+    public static class GiniData extends ContinuousRegionInfo {
+        /** Sum of squares of counts of each label. */
+        private double c2;
+
+        /** Counts of each label. On i-th position there is count of label which is mapped to index i. */
+        private int[] m;
+
+        /**
+         * Create Gini data.
+         *
+         * @param impurity Impurity (i.e. Gini impurity).
+         * @param size Count of samples.
+         * @param m Counts of each label.
+         * @param c2 Sum of squares of counts of each label.
+         */
+        public GiniData(double impurity, int size, int[] m, double c2) {
+            super(impurity, size);
+            this.m = m;
+            this.c2 = c2;
+        }
+
+        /**
+         * No-op constructor for serialization/deserialization..
+         */
+        public GiniData() {
+            // No-op.
+        }
+
+        /** Get counts of each label. */
+        public int[] counts() {
+            return m;
+        }
+
+        /** {@inheritDoc} */
+        @Override public void writeExternal(ObjectOutput out) throws IOException {
+            super.writeExternal(out);
+            out.writeDouble(c2);
+            out.writeInt(m.length);
+            for (int i : m)
+                out.writeInt(i);
+
+        }
+
+        /** {@inheritDoc} */
+        @Override public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
+            super.readExternal(in);
+
+            c2 = in.readDouble();
+            int size = in.readInt();
+            m = new int[size];
+
+            for (int i = 0; i < size; i++)
+                m[i] = in.readInt();
+        }
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/contsplitcalcs/VarianceSplitCalculator.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/contsplitcalcs/VarianceSplitCalculator.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/contsplitcalcs/VarianceSplitCalculator.java
new file mode 100644
index 0000000..66c54f2
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/contsplitcalcs/VarianceSplitCalculator.java
@@ -0,0 +1,179 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased.contsplitcalcs;
+
+import java.io.IOException;
+import java.io.ObjectInput;
+import java.io.ObjectOutput;
+import java.util.PrimitiveIterator;
+import java.util.stream.DoubleStream;
+import org.apache.ignite.ml.trees.ContinuousRegionInfo;
+import org.apache.ignite.ml.trees.ContinuousSplitCalculator;
+import org.apache.ignite.ml.trees.trainers.columnbased.vectors.ContinuousSplitInfo;
+import org.apache.ignite.ml.trees.trainers.columnbased.vectors.SplitInfo;
+
+/**
+ * Calculator of variance in a given region.
+ */
+public class VarianceSplitCalculator implements ContinuousSplitCalculator<VarianceSplitCalculator.VarianceData> {
+    /**
+     * Data used in variance calculations.
+     */
+    public static class VarianceData extends ContinuousRegionInfo {
+        /** Mean value in a given region. */
+        double mean;
+
+        /**
+         * @param var Variance in this region.
+         * @param size Size of data for which variance is calculated.
+         * @param mean Mean value in this region.
+         */
+        public VarianceData(double var, int size, double mean) {
+            super(var, size);
+            this.mean = mean;
+        }
+
+        /**
+         * No-op constructor. For serialization/deserialization.
+         */
+        public VarianceData() {
+            // No-op.
+        }
+
+        /** {@inheritDoc} */
+        @Override public void writeExternal(ObjectOutput out) throws IOException {
+            super.writeExternal(out);
+            out.writeDouble(mean);
+        }
+
+        /** {@inheritDoc} */
+        @Override public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
+            super.readExternal(in);
+            mean = in.readDouble();
+        }
+
+        /**
+         * Returns mean.
+         */
+        public double mean() {
+            return mean;
+        }
+    }
+
+    /** {@inheritDoc} */
+    @Override public VarianceData calculateRegionInfo(DoubleStream s, int size) {
+        PrimitiveIterator.OfDouble itr = s.iterator();
+        int i = 0;
+
+        double mean = 0.0;
+        double m2 = 0.0;
+
+        // Here we calculate variance and mean by incremental computation.
+        while (itr.hasNext()) {
+            i++;
+            double x = itr.next();
+            double delta = x - mean;
+            mean += delta / i;
+            double delta2 = x - mean;
+            m2 += delta * delta2;
+        }
+
+        return new VarianceData(m2 / i, size, mean);
+    }
+
+    /** {@inheritDoc} */
+    @Override public SplitInfo<VarianceData> splitRegion(Integer[] s, double[] values, double[] labels, int regionIdx,
+        VarianceData d) {
+        int size = d.getSize();
+
+        double lm2 = 0.0;
+        double rm2 = d.impurity() * size;
+        int lSize = size;
+
+        double lMean = 0.0;
+        double rMean = d.mean;
+
+        double minImpurity = d.impurity() * size;
+        double curThreshold;
+        double curImpurity;
+        double threshold = Double.NEGATIVE_INFINITY;
+
+        int i = 0;
+        int nextIdx = s[0];
+        i++;
+        double[] lrImps = new double[] {lm2, rm2, lMean, rMean};
+
+        do {
+            // Process all values equal to prev.
+            while (i < s.length) {
+                moveLeft(labels[nextIdx], lrImps[2], i, lrImps[0], lrImps[3], size - i, lrImps[1], lrImps);
+                curImpurity = (lrImps[0] + lrImps[1]);
+                curThreshold = values[nextIdx];
+
+                if (values[nextIdx] != values[(nextIdx = s[i++])]) {
+                    if (curImpurity < minImpurity) {
+                        lSize = i - 1;
+
+                        lm2 = lrImps[0];
+                        rm2 = lrImps[1];
+
+                        lMean = lrImps[2];
+                        rMean = lrImps[3];
+
+                        minImpurity = curImpurity;
+                        threshold = curThreshold;
+                    }
+
+                    break;
+                }
+            }
+        }
+        while (i < s.length - 1);
+
+        if (lSize == size)
+            return null;
+
+        VarianceData lData = new VarianceData(lm2 / (lSize != 0 ? lSize : 1), lSize, lMean);
+        int rSize = size - lSize;
+        VarianceData rData = new VarianceData(rm2 / (rSize != 0 ? rSize : 1), rSize, rMean);
+
+        return new ContinuousSplitInfo<>(regionIdx, threshold, lData, rData);
+    }
+
+    /**
+     * Add point to the left interval and remove it from the right interval and calculate necessary statistics on
+     * intervals with new bounds.
+     */
+    private void moveLeft(double x, double lMean, int lSize, double lm2, double rMean, int rSize, double rm2,
+        double[] data) {
+        // We add point to the left interval.
+        double lDelta = x - lMean;
+        double lMeanNew = lMean + lDelta / lSize;
+        double lm2New = lm2 + lDelta * (x - lMeanNew);
+
+        // We remove point from the right interval. lSize + 1 is the size of right interval before removal.
+        double rMeanNew = (rMean * (rSize + 1) - x) / rSize;
+        double rm2New = rm2 - (x - rMean) * (x - rMeanNew);
+
+        data[0] = lm2New;
+        data[1] = rm2New;
+
+        data[2] = lMeanNew;
+        data[3] = rMeanNew;
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/contsplitcalcs/package-info.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/contsplitcalcs/package-info.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/contsplitcalcs/package-info.java
new file mode 100644
index 0000000..08c8a75
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/contsplitcalcs/package-info.java
@@ -0,0 +1,22 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * <!-- Package description. -->
+ * Calculators of splits by continuous features.
+ */
+package org.apache.ignite.ml.trees.trainers.columnbased.contsplitcalcs;
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/package-info.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/package-info.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/package-info.java
new file mode 100644
index 0000000..8523914
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/package-info.java
@@ -0,0 +1,22 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * <!-- Package description. -->
+ * Contains column based decision tree algorithms.
+ */
+package org.apache.ignite.ml.trees.trainers.columnbased;
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/regcalcs/RegionCalculators.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/regcalcs/RegionCalculators.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/regcalcs/RegionCalculators.java
new file mode 100644
index 0000000..5c4b354
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/regcalcs/RegionCalculators.java
@@ -0,0 +1,85 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased.regcalcs;
+
+import it.unimi.dsi.fastutil.doubles.Double2IntOpenHashMap;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.PrimitiveIterator;
+import java.util.stream.DoubleStream;
+import org.apache.ignite.ml.math.functions.IgniteFunction;
+import org.apache.ignite.ml.trees.trainers.columnbased.ColumnDecisionTreeTrainerInput;
+
+/** Some commonly used functions for calculations of regions of space which correspond to decision tree leaf nodes. */
+public class RegionCalculators {
+    /** Mean value in the region. */
+    public static final IgniteFunction<DoubleStream, Double> MEAN = s -> s.average().orElse(0.0);
+
+    /** Most common value in the region. */
+    public static final IgniteFunction<DoubleStream, Double> MOST_COMMON =
+        s -> {
+            PrimitiveIterator.OfDouble itr = s.iterator();
+            Map<Double, Integer> voc = new HashMap<>();
+
+            while (itr.hasNext())
+                voc.compute(itr.next(), (d, i) -> i != null ? i + 1 : 0);
+
+            return voc.entrySet().stream().max(Comparator.comparing(Map.Entry::getValue)).map(Map.Entry::getKey).orElse(0.0);
+        };
+
+    /** Variance of a region. */
+    public static final IgniteFunction<ColumnDecisionTreeTrainerInput, IgniteFunction<DoubleStream, Double>> VARIANCE = input ->
+        s -> {
+            PrimitiveIterator.OfDouble itr = s.iterator();
+            int i = 0;
+
+            double mean = 0.0;
+            double m2 = 0.0;
+
+            while (itr.hasNext()) {
+                i++;
+                double x = itr.next();
+                double delta = x - mean;
+                mean += delta / i;
+                double delta2 = x - mean;
+                m2 += delta * delta2;
+            }
+
+            return i > 0 ? m2 / i : 0.0;
+        };
+
+    /** Gini impurity of a region. */
+    public static final IgniteFunction<ColumnDecisionTreeTrainerInput, IgniteFunction<DoubleStream, Double>> GINI = input ->
+        s -> {
+            PrimitiveIterator.OfDouble itr = s.iterator();
+
+            Double2IntOpenHashMap m = new Double2IntOpenHashMap();
+
+            int size = 0;
+
+            while (itr.hasNext()) {
+                size++;
+                m.compute(itr.next(), (a, i) -> i != null ? i + 1 : 1);
+            }
+
+            double c2 = m.values().stream().mapToDouble(v -> v * v).sum();
+
+            return size != 0 ? 1 - c2 / (size * size) : 0.0;
+        };
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/regcalcs/package-info.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/regcalcs/package-info.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/regcalcs/package-info.java
new file mode 100644
index 0000000..e8edd8f
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/regcalcs/package-info.java
@@ -0,0 +1,22 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * <!-- Package description. -->
+ * Region calculators.
+ */
+package org.apache.ignite.ml.trees.trainers.columnbased.regcalcs;
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/CategoricalFeatureProcessor.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/CategoricalFeatureProcessor.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/CategoricalFeatureProcessor.java
new file mode 100644
index 0000000..9469768
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/CategoricalFeatureProcessor.java
@@ -0,0 +1,211 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased.vectors;
+
+import com.zaxxer.sparsebits.SparseBitSet;
+import java.util.Arrays;
+import java.util.BitSet;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.DoubleStream;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+import org.apache.ignite.lang.IgniteBiTuple;
+import org.apache.ignite.ml.math.functions.IgniteFunction;
+import org.apache.ignite.ml.trees.CategoricalRegionInfo;
+import org.apache.ignite.ml.trees.CategoricalSplitInfo;
+import org.apache.ignite.ml.trees.RegionInfo;
+import org.apache.ignite.ml.trees.trainers.columnbased.RegionProjection;
+
+import static org.apache.ignite.ml.trees.trainers.columnbased.vectors.FeatureVectorProcessorUtils.splitByBitSet;
+
+/**
+ * Categorical feature vector processor implementation used by {@see ColumnDecisionTreeTrainer}.
+ */
+public class CategoricalFeatureProcessor
+    implements FeatureProcessor<CategoricalRegionInfo, CategoricalSplitInfo<CategoricalRegionInfo>> {
+    /** Count of categories for this feature. */
+    private final int catsCnt;
+
+    /** Function for calculating impurity of a given region of points. */
+    private final IgniteFunction<DoubleStream, Double> calc;
+
+    /**
+     * @param calc Function for calculating impurity of a given region of points.
+     * @param catsCnt Number of categories.
+     */
+    public CategoricalFeatureProcessor(IgniteFunction<DoubleStream, Double> calc, int catsCnt) {
+        this.calc = calc;
+        this.catsCnt = catsCnt;
+    }
+
+    /** */
+    private SplitInfo<CategoricalRegionInfo> split(BitSet leftCats, int intervalIdx, Map<Integer, Integer> mapping,
+        Integer[] sampleIndexes, double[] values, double[] labels, double impurity) {
+        Map<Boolean, List<Integer>> leftRight = Arrays.stream(sampleIndexes).
+            collect(Collectors.partitioningBy((smpl) -> leftCats.get(mapping.get((int)values[smpl]))));
+
+        List<Integer> left = leftRight.get(true);
+        int leftSize = left.size();
+        double leftImpurity = calc.apply(left.stream().mapToDouble(s -> labels[s]));
+
+        List<Integer> right = leftRight.get(false);
+        int rightSize = right.size();
+        double rightImpurity = calc.apply(right.stream().mapToDouble(s -> labels[s]));
+
+        int totalSize = leftSize + rightSize;
+
+        // Result of this call will be sent back to trainer node, we do not need vectors inside of sent data.
+        CategoricalSplitInfo<CategoricalRegionInfo> res = new CategoricalSplitInfo<>(intervalIdx,
+            new CategoricalRegionInfo(leftImpurity, null), // cats can be computed on the last step.
+            new CategoricalRegionInfo(rightImpurity, null),
+            leftCats);
+
+        res.setInfoGain(impurity - (double)leftSize / totalSize * leftImpurity - (double)rightSize / totalSize * rightImpurity);
+        return res;
+    }
+
+    /**
+     * Get a stream of subsets given categories count.
+     *
+     * @param catsCnt categories count.
+     * @return Stream of subsets given categories count.
+     */
+    private Stream<BitSet> powerSet(int catsCnt) {
+        Iterable<BitSet> iterable = () -> new PSI(catsCnt);
+        return StreamSupport.stream(iterable.spliterator(), false);
+    }
+
+    /** {@inheritDoc} */
+    @Override public SplitInfo findBestSplit(RegionProjection<CategoricalRegionInfo> regionPrj, double[] values,
+        double[] labels, int regIdx) {
+        Map<Integer, Integer> mapping = mapping(regionPrj.data().cats());
+
+        return powerSet(regionPrj.data().cats().length()).
+            map(s -> split(s, regIdx, mapping, regionPrj.sampleIndexes(), values, labels, regionPrj.data().impurity())).
+            max(Comparator.comparingDouble(SplitInfo::infoGain)).
+            orElse(null);
+    }
+
+    /** {@inheritDoc} */
+    @Override public RegionProjection<CategoricalRegionInfo> createInitialRegion(Integer[] sampleIndexes,
+        double[] values, double[] labels) {
+        BitSet set = new BitSet();
+        set.set(0, catsCnt);
+
+        Double impurity = calc.apply(Arrays.stream(labels));
+
+        return new RegionProjection<>(sampleIndexes, new CategoricalRegionInfo(impurity, set), 0);
+    }
+
+    /** {@inheritDoc} */
+    @Override public SparseBitSet calculateOwnershipBitSet(RegionProjection<CategoricalRegionInfo> regionPrj,
+        double[] values,
+        CategoricalSplitInfo<CategoricalRegionInfo> s) {
+        SparseBitSet res = new SparseBitSet();
+        Arrays.stream(regionPrj.sampleIndexes()).forEach(smpl -> res.set(smpl, s.bitSet().get((int)values[smpl])));
+        return res;
+    }
+
+    /** {@inheritDoc} */
+    @Override public IgniteBiTuple<RegionProjection, RegionProjection> performSplit(SparseBitSet bs,
+        RegionProjection<CategoricalRegionInfo> reg, CategoricalRegionInfo leftData, CategoricalRegionInfo rightData) {
+        return performSplitGeneric(bs, null, reg, leftData, rightData);
+    }
+
+    /** {@inheritDoc} */
+    @Override public IgniteBiTuple<RegionProjection, RegionProjection> performSplitGeneric(
+        SparseBitSet bs, double[] values, RegionProjection<CategoricalRegionInfo> reg, RegionInfo leftData,
+        RegionInfo rightData) {
+        int depth = reg.depth();
+
+        int lSize = bs.cardinality();
+        int rSize = reg.sampleIndexes().length - lSize;
+        IgniteBiTuple<Integer[], Integer[]> lrSamples = splitByBitSet(lSize, rSize, reg.sampleIndexes(), bs);
+        BitSet leftCats = calculateCats(lrSamples.get1(), values);
+        CategoricalRegionInfo lInfo = new CategoricalRegionInfo(leftData.impurity(), leftCats);
+
+        // TODO: IGNITE-5892 Check how it will work with sparse data.
+        BitSet rightCats = calculateCats(lrSamples.get2(), values);
+        CategoricalRegionInfo rInfo = new CategoricalRegionInfo(rightData.impurity(), rightCats);
+
+        RegionProjection<CategoricalRegionInfo> rPrj = new RegionProjection<>(lrSamples.get2(), rInfo, depth + 1);
+        RegionProjection<CategoricalRegionInfo> lPrj = new RegionProjection<>(lrSamples.get1(), lInfo, depth + 1);
+        return new IgniteBiTuple<>(lPrj, rPrj);
+    }
+
+    /**
+     * Powerset iterator. Iterates not over the whole powerset, but on half of it.
+     */
+    private static class PSI implements Iterator<BitSet> {
+
+        /** Current subset number. */
+        private int i = 1; // We are not interested in {emptyset, set} split and therefore start from 1.
+
+        /** Size of set, subsets of which we iterate over. */
+        final int size;
+
+        /**
+         * @param bitCnt Size of set, subsets of which we iterate over.
+         */
+        PSI(int bitCnt) {
+            this.size = 1 << (bitCnt - 1);
+        }
+
+        /** {@inheritDoc} */
+        @Override public boolean hasNext() {
+            return i < size;
+        }
+
+        /** {@inheritDoc} */
+        @Override public BitSet next() {
+            BitSet res = BitSet.valueOf(new long[] {i});
+            i++;
+            return res;
+        }
+    }
+
+    /** */
+    private Map<Integer, Integer> mapping(BitSet bs) {
+        int bn = 0;
+        Map<Integer, Integer> res = new HashMap<>();
+
+        int i = 0;
+        while ((bn = bs.nextSetBit(bn)) != -1) {
+            res.put(bn, i);
+            i++;
+            bn++;
+        }
+
+        return res;
+    }
+
+    /** Get set of categories of given samples */
+    private BitSet calculateCats(Integer[] sampleIndexes, double[] values) {
+        BitSet res = new BitSet();
+
+        for (int smpl : sampleIndexes)
+            res.set((int)values[smpl]);
+
+        return res;
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/ContinuousFeatureProcessor.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/ContinuousFeatureProcessor.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/ContinuousFeatureProcessor.java
new file mode 100644
index 0000000..4117993
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/ContinuousFeatureProcessor.java
@@ -0,0 +1,111 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased.vectors;
+
+import com.zaxxer.sparsebits.SparseBitSet;
+import java.util.Arrays;
+import java.util.Comparator;
+import org.apache.ignite.lang.IgniteBiTuple;
+import org.apache.ignite.ml.trees.ContinuousRegionInfo;
+import org.apache.ignite.ml.trees.ContinuousSplitCalculator;
+import org.apache.ignite.ml.trees.RegionInfo;
+import org.apache.ignite.ml.trees.trainers.columnbased.RegionProjection;
+
+import static org.apache.ignite.ml.trees.trainers.columnbased.vectors.FeatureVectorProcessorUtils.splitByBitSet;
+
+/**
+ * Container of projection of samples on continuous feature.
+ *
+ * @param <D> Information about regions. Designed to contain information which will make computations of impurity
+ * optimal.
+ */
+public class ContinuousFeatureProcessor<D extends ContinuousRegionInfo> implements
+    FeatureProcessor<D, ContinuousSplitInfo<D>> {
+    /** ContinuousSplitCalculator used for calculating of best split of each region. */
+    private final ContinuousSplitCalculator<D> calc;
+
+    /**
+     * @param splitCalc Calculator used for calculating splits.
+     */
+    public ContinuousFeatureProcessor(ContinuousSplitCalculator<D> splitCalc) {
+        this.calc = splitCalc;
+    }
+
+    /** {@inheritDoc} */
+    @Override public SplitInfo<D> findBestSplit(RegionProjection<D> ri, double[] values, double[] labels, int regIdx) {
+        SplitInfo<D> res = calc.splitRegion(ri.sampleIndexes(), values, labels, regIdx, ri.data());
+
+        if (res == null)
+            return null;
+
+        double lWeight = (double)res.leftData.getSize() / ri.sampleIndexes().length;
+        double rWeight = (double)res.rightData.getSize() / ri.sampleIndexes().length;
+
+        double infoGain = ri.data().impurity() - lWeight * res.leftData().impurity() - rWeight * res.rightData().impurity();
+        res.setInfoGain(infoGain);
+
+        return res;
+    }
+
+    /** {@inheritDoc} */
+    @Override public RegionProjection<D> createInitialRegion(Integer[] samples, double[] values, double[] labels) {
+        Arrays.sort(samples, Comparator.comparingDouble(s -> values[s]));
+        return new RegionProjection<>(samples, calc.calculateRegionInfo(Arrays.stream(labels), samples.length), 0);
+    }
+
+    /** {@inheritDoc} */
+    @Override public SparseBitSet calculateOwnershipBitSet(RegionProjection<D> reg, double[] values,
+        ContinuousSplitInfo<D> s) {
+        SparseBitSet res = new SparseBitSet();
+
+        for (int i = 0; i < s.leftData().getSize(); i++)
+            res.set(reg.sampleIndexes()[i]);
+
+        return res;
+    }
+
+    /** {@inheritDoc} */
+    @Override public IgniteBiTuple<RegionProjection, RegionProjection> performSplit(SparseBitSet bs,
+        RegionProjection<D> reg, D leftData, D rightData) {
+        int lSize = leftData.getSize();
+        int rSize = rightData.getSize();
+        int depth = reg.depth();
+
+        IgniteBiTuple<Integer[], Integer[]> lrSamples = splitByBitSet(lSize, rSize, reg.sampleIndexes(), bs);
+
+        RegionProjection<D> left = new RegionProjection<>(lrSamples.get1(), leftData, depth + 1);
+        RegionProjection<D> right = new RegionProjection<>(lrSamples.get2(), rightData, depth + 1);
+
+        return new IgniteBiTuple<>(left, right);
+    }
+
+    /** {@inheritDoc} */
+    @Override public IgniteBiTuple<RegionProjection, RegionProjection> performSplitGeneric(SparseBitSet bs,
+        double[] labels, RegionProjection<D> reg, RegionInfo leftData, RegionInfo rightData) {
+        int lSize = bs.cardinality();
+        int rSize = reg.sampleIndexes().length - lSize;
+        int depth = reg.depth();
+
+        IgniteBiTuple<Integer[], Integer[]> lrSamples = splitByBitSet(lSize, rSize, reg.sampleIndexes(), bs);
+
+        D ld = calc.calculateRegionInfo(Arrays.stream(lrSamples.get1()).mapToDouble(s -> labels[s]), lSize);
+        D rd = calc.calculateRegionInfo(Arrays.stream(lrSamples.get2()).mapToDouble(s -> labels[s]), rSize);
+
+        return new IgniteBiTuple<>(new RegionProjection<>(lrSamples.get1(), ld, depth + 1), new RegionProjection<>(lrSamples.get2(), rd, depth + 1));
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/ContinuousSplitInfo.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/ContinuousSplitInfo.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/ContinuousSplitInfo.java
new file mode 100644
index 0000000..d6f2847
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/ContinuousSplitInfo.java
@@ -0,0 +1,54 @@
+package org.apache.ignite.ml.trees.trainers.columnbased.vectors;
+
+import org.apache.ignite.ml.trees.RegionInfo;
+import org.apache.ignite.ml.trees.nodes.ContinuousSplitNode;
+import org.apache.ignite.ml.trees.nodes.SplitNode;
+
+/**
+ * Information about split of continuous region.
+ *
+ * @param <D> Class encapsulating information about the region.
+ */
+public class ContinuousSplitInfo<D extends RegionInfo> extends SplitInfo<D> {
+    /**
+     * Threshold used for split.
+     * Samples with values less or equal than this go to left region, others go to the right region.
+     */
+    private final double threshold;
+
+    /**
+     * @param regionIdx Index of region being split.
+     * @param threshold Threshold used for split. Samples with values less or equal than this go to left region, others
+     * go to the right region.
+     * @param leftData Information about left subregion.
+     * @param rightData Information about right subregion.
+     */
+    public ContinuousSplitInfo(int regionIdx, double threshold, D leftData, D rightData) {
+        super(regionIdx, leftData, rightData);
+        this.threshold = threshold;
+    }
+
+    /** {@inheritDoc} */
+    @Override public SplitNode createSplitNode(int featureIdx) {
+        return new ContinuousSplitNode(threshold, featureIdx);
+    }
+
+    /**
+     * Threshold used for splits.
+     * Samples with values less or equal than this go to left region, others go to the right region.
+     */
+    public double threshold() {
+        return threshold;
+    }
+
+    /** {@inheritDoc} */
+    @Override public String toString() {
+        return "ContinuousSplitInfo [" +
+            "threshold=" + threshold +
+            ", infoGain=" + infoGain +
+            ", regionIdx=" + regionIdx +
+            ", leftData=" + leftData +
+            ", rightData=" + rightData +
+            ']';
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/FeatureProcessor.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/FeatureProcessor.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/FeatureProcessor.java
new file mode 100644
index 0000000..cb8f5c2
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/FeatureProcessor.java
@@ -0,0 +1,81 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased.vectors;
+
+import com.zaxxer.sparsebits.SparseBitSet;
+import org.apache.ignite.lang.IgniteBiTuple;
+import org.apache.ignite.ml.trees.RegionInfo;
+import org.apache.ignite.ml.trees.trainers.columnbased.RegionProjection;
+
+/**
+ * Base interface for feature processors used in {@see org.apache.ignite.ml.trees.trainers.columnbased.ColumnDecisionTreeTrainer}
+ *
+ * @param <D> Class representing data of regions resulted from split.
+ * @param <S> Class representing data of split.
+ */
+public interface FeatureProcessor<D extends RegionInfo, S extends SplitInfo<D>> {
+    /**
+     * Finds best split by this feature among all splits of all regions.
+     *
+     * @return best split by this feature among all splits of all regions.
+     */
+    SplitInfo findBestSplit(RegionProjection<D> regionPrj, double[] values, double[] labels, int regIdx);
+
+    /**
+     * Creates initial region from samples.
+     *
+     * @param samples samples.
+     * @return region.
+     */
+    RegionProjection<D> createInitialRegion(Integer[] samples, double[] values, double[] labels);
+
+    /**
+     * Calculates the bitset mapping each data point to left (corresponding bit is set) or right subregion.
+     *
+     * @param s data used for calculating the split.
+     * @return Bitset mapping each data point to left (corresponding bit is set) or right subregion.
+     */
+    SparseBitSet calculateOwnershipBitSet(RegionProjection<D> regionPrj, double[] values, S s);
+
+    /**
+     * Splits given region using bitset which maps data point to left or right subregion.
+     * This method is present for the vectors of the same type to be able to pass between them information about regions
+     * and therefore used iff the optimal split is received on feature of the same type.
+     *
+     * @param bs Bitset which maps data point to left or right subregion.
+     * @param leftData Data of the left subregion.
+     * @param rightData Data of the right subregion.
+     * @return This feature vector.
+     */
+    IgniteBiTuple<RegionProjection, RegionProjection> performSplit(SparseBitSet bs, RegionProjection<D> reg, D leftData,
+        D rightData);
+
+    /**
+     * Splits given region using bitset which maps data point to left or right subregion. This method is used iff the
+     * optimal split is received on feature of different type, therefore information about regions is limited to the
+     * {@see RegionInfo} class which is base for all classes used to represent region data.
+     *
+     * @param bs Bitset which maps data point to left or right subregion.
+     * @param leftData Data of the left subregion.
+     * @param rightData Data of the right subregion.
+     * @return This feature vector.
+     */
+    IgniteBiTuple<RegionProjection, RegionProjection> performSplitGeneric(SparseBitSet bs, double[] values,
+        RegionProjection<D> reg, RegionInfo leftData,
+        RegionInfo rightData);
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/FeatureVectorProcessorUtils.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/FeatureVectorProcessorUtils.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/FeatureVectorProcessorUtils.java
new file mode 100644
index 0000000..69ff019
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/FeatureVectorProcessorUtils.java
@@ -0,0 +1,57 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased.vectors;
+
+import com.zaxxer.sparsebits.SparseBitSet;
+import org.apache.ignite.lang.IgniteBiTuple;
+
+/** Utility class for feature vector processors. */
+public class FeatureVectorProcessorUtils {
+    /**
+     * Split target array into two (left and right) arrays by bitset.
+     *
+     * @param lSize Left array size;
+     * @param rSize Right array size.
+     * @param samples Arrays to split size.
+     * @param bs Bitset specifying split.
+     * @return BiTuple containing result of split.
+     */
+    public static IgniteBiTuple<Integer[], Integer[]> splitByBitSet(int lSize, int rSize, Integer[] samples,
+        SparseBitSet bs) {
+        Integer[] lArr = new Integer[lSize];
+        Integer[] rArr = new Integer[rSize];
+
+        int lc = 0;
+        int rc = 0;
+
+        for (int i = 0; i < lSize + rSize; i++) {
+            int si = samples[i];
+
+            if (bs.get(si)) {
+                lArr[lc] = si;
+                lc++;
+            }
+            else {
+                rArr[rc] = si;
+                rc++;
+            }
+        }
+
+        return new IgniteBiTuple<>(lArr, rArr);
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/SampleInfo.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/SampleInfo.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/SampleInfo.java
new file mode 100644
index 0000000..8aa4f79
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/SampleInfo.java
@@ -0,0 +1,80 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased.vectors;
+
+import java.io.Externalizable;
+import java.io.IOException;
+import java.io.ObjectInput;
+import java.io.ObjectOutput;
+
+/**
+ * Information about given sample within given fixed feature.
+ */
+public class SampleInfo implements Externalizable {
+    /** Value of projection of this sample on given fixed feature. */
+    private double val;
+
+    /** Sample index. */
+    private int sampleIdx;
+
+    /**
+     * @param val Value of projection of this sample on given fixed feature.
+     * @param sampleIdx Sample index.
+     */
+    public SampleInfo(double val, int sampleIdx) {
+        this.val = val;
+        this.sampleIdx = sampleIdx;
+    }
+
+    /**
+     * No-op constructor used for serialization/deserialization.
+     */
+    public SampleInfo() {
+        // No-op.
+    }
+
+    /**
+     * Get the value of projection of this sample on given fixed feature.
+     *
+     * @return Value of projection of this sample on given fixed feature.
+     */
+    public double val() {
+        return val;
+    }
+
+    /**
+     * Get the sample index.
+     *
+     * @return Sample index.
+     */
+    public int sampleInd() {
+        return sampleIdx;
+    }
+
+    /** {@inheritDoc} */
+    @Override public void writeExternal(ObjectOutput out) throws IOException {
+        out.writeDouble(val);
+        out.writeInt(sampleIdx);
+    }
+
+    /** {@inheritDoc} */
+    @Override public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
+        val = in.readDouble();
+        sampleIdx = in.readInt();
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/SplitInfo.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/SplitInfo.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/SplitInfo.java
new file mode 100644
index 0000000..124e82f
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/SplitInfo.java
@@ -0,0 +1,106 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased.vectors;
+
+import org.apache.ignite.ml.trees.RegionInfo;
+import org.apache.ignite.ml.trees.nodes.SplitNode;
+
+/**
+ * Class encapsulating information about the split.
+ *
+ * @param <D> Class representing information of left and right subregions.
+ */
+public abstract class SplitInfo<D extends RegionInfo> {
+    /** Information gain of this split. */
+    protected double infoGain;
+
+    /** Index of the region to split. */
+    protected final int regionIdx;
+
+    /** Data of left subregion. */
+    protected final D leftData;
+
+    /** Data of right subregion. */
+    protected final D rightData;
+
+    /**
+     * Construct the split info.
+     *
+     * @param regionIdx Index of the region to split.
+     * @param leftData Data of left subregion.
+     * @param rightData Data of right subregion.
+     */
+    public SplitInfo(int regionIdx, D leftData, D rightData) {
+        this.regionIdx = regionIdx;
+        this.leftData = leftData;
+        this.rightData = rightData;
+    }
+
+    /**
+     * Index of region to split.
+     *
+     * @return Index of region to split.
+     */
+    public int regionIndex() {
+        return regionIdx;
+    }
+
+    /**
+     * Information gain of the split.
+     *
+     * @return Information gain of the split.
+     */
+    public double infoGain() {
+        return infoGain;
+    }
+
+    /**
+     * Data of right subregion.
+     *
+     * @return Data of right subregion.
+     */
+    public D rightData() {
+        return rightData;
+    }
+
+    /**
+     * Data of left subregion.
+     *
+     * @return Data of left subregion.
+     */
+    public D leftData() {
+        return leftData;
+    }
+
+    /**
+     * Create SplitNode from this split info.
+     *
+     * @param featureIdx Index of feature by which goes split.
+     * @return SplitNode from this split info.
+     */
+    public abstract SplitNode createSplitNode(int featureIdx);
+
+    /**
+     * Set information gain.
+     *
+     * @param infoGain Information gain.
+     */
+    public void setInfoGain(double infoGain) {
+        this.infoGain = infoGain;
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/package-info.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/package-info.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/package-info.java
new file mode 100644
index 0000000..0dea204
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/vectors/package-info.java
@@ -0,0 +1,22 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * <!-- Package description. -->
+ * Contains feature containers needed by column based decision tree trainers.
+ */
+package org.apache.ignite.ml.trees.trainers.columnbased.vectors;
\ No newline at end of file


[3/4] ignite git commit: IGNITE-5218: First version of decision trees. This closes #2936

Posted by is...@apache.org.
http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/ContinuousRegionInfo.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/ContinuousRegionInfo.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/ContinuousRegionInfo.java
new file mode 100644
index 0000000..e98bb72
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/ContinuousRegionInfo.java
@@ -0,0 +1,74 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees;
+
+import java.io.IOException;
+import java.io.ObjectInput;
+import java.io.ObjectOutput;
+
+/**
+ * Information about region used by continuous features.
+ */
+public class ContinuousRegionInfo extends RegionInfo {
+    /**
+     * Count of samples in this region.
+     */
+    private int size;
+
+    /**
+     * @param impurity Impurity of the region.
+     * @param size Size of this region
+     */
+    public ContinuousRegionInfo(double impurity, int size) {
+        super(impurity);
+        this.size = size;
+    }
+
+    /**
+     * No-op constructor for serialization/deserialization.
+     */
+    public ContinuousRegionInfo() {
+        // No-op
+    }
+
+    /**
+     * Get the size of region.
+     */
+    public int getSize() {
+        return size;
+    }
+
+    /** {@inheritDoc} */
+    @Override public String toString() {
+        return "ContinuousRegionInfo [" +
+            "size=" + size +
+            ']';
+    }
+
+    /** {@inheritDoc} */
+    @Override public void writeExternal(ObjectOutput out) throws IOException {
+        super.writeExternal(out);
+        out.writeInt(size);
+    }
+
+    /** {@inheritDoc} */
+    @Override public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
+        super.readExternal(in);
+        size = in.readInt();
+    }
+}
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/ContinuousSplitCalculator.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/ContinuousSplitCalculator.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/ContinuousSplitCalculator.java
new file mode 100644
index 0000000..f9b81d0
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/ContinuousSplitCalculator.java
@@ -0,0 +1,50 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees;
+
+import java.util.stream.DoubleStream;
+import org.apache.ignite.ml.trees.trainers.columnbased.vectors.SplitInfo;
+
+/**
+ * This class is used for calculation of best split by continuous feature.
+ *
+ * @param <C> Class in which information about region will be stored.
+ */
+public interface ContinuousSplitCalculator<C extends ContinuousRegionInfo> {
+    /**
+     * Calculate region info 'from scratch'.
+     *
+     * @param s Stream of labels in this region.
+     * @param l Index of sample projection on this feature in array sorted by this projection value and intervals
+     * bitsets. ({@see org.apache.ignite.ml.trees.trainers.columnbased.vectors.ContinuousFeatureProcessor}).
+     * @return Region info.
+     */
+    C calculateRegionInfo(DoubleStream s, int l);
+
+    /**
+     * Calculate split info of best split of region given information about this region.
+     *
+     * @param sampleIndexes Indexes of samples of this region.
+     * @param values All values of this feature.
+     * @param labels All labels of this feature.
+     * @param regionIdx Index of region being split.
+     * @param data Information about region being split which can be used for computations.
+     * @return Information about best split of region with index given by regionIdx.
+     */
+    SplitInfo<C> splitRegion(Integer[] sampleIndexes, double[] values, double[] labels, int regionIdx, C data);
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/RegionInfo.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/RegionInfo.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/RegionInfo.java
new file mode 100644
index 0000000..8ec7db3
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/RegionInfo.java
@@ -0,0 +1,62 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees;
+
+import java.io.Externalizable;
+import java.io.IOException;
+import java.io.ObjectInput;
+import java.io.ObjectOutput;
+
+/** Class containing information about region. */
+public class RegionInfo implements Externalizable {
+    /** Impurity in this region. */
+    private double impurity;
+
+    /**
+     * @param impurity Impurity of this region.
+     */
+    public RegionInfo(double impurity) {
+        this.impurity = impurity;
+    }
+
+    /**
+     * No-op constructor for serialization/deserialization.
+     */
+    public RegionInfo() {
+        // No-op
+    }
+
+    /**
+     * Get impurity in this region.
+     *
+     * @return Impurity of this region.
+     */
+    public double impurity() {
+        return impurity;
+    }
+
+    /** {@inheritDoc} */
+    @Override public void writeExternal(ObjectOutput out) throws IOException {
+        out.writeDouble(impurity);
+    }
+
+    /** {@inheritDoc} */
+    @Override public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
+        impurity = in.readDouble();
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/models/DecisionTreeModel.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/models/DecisionTreeModel.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/models/DecisionTreeModel.java
new file mode 100644
index 0000000..86e9326
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/models/DecisionTreeModel.java
@@ -0,0 +1,44 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.models;
+
+import org.apache.ignite.ml.Model;
+import org.apache.ignite.ml.math.Vector;
+import org.apache.ignite.ml.trees.nodes.DecisionTreeNode;
+
+/**
+ * Model for decision tree.
+ */
+public class DecisionTreeModel implements Model<Vector, Double> {
+    /** Root node of the decision tree. */
+    private final DecisionTreeNode root;
+
+    /**
+     * Construct decision tree model.
+     *
+     * @param root Root of decision tree.
+     */
+    public DecisionTreeModel(DecisionTreeNode root) {
+        this.root = root;
+    }
+
+    /** {@inheritDoc} */
+    @Override public Double predict(Vector val) {
+        return root.process(val);
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/models/package-info.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/models/package-info.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/models/package-info.java
new file mode 100644
index 0000000..ce8418e
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/models/package-info.java
@@ -0,0 +1,22 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * <!-- Package description. -->
+ * Contains decision tree models.
+ */
+package org.apache.ignite.ml.trees.models;
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/CategoricalSplitNode.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/CategoricalSplitNode.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/CategoricalSplitNode.java
new file mode 100644
index 0000000..cae6d4a
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/CategoricalSplitNode.java
@@ -0,0 +1,50 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.nodes;
+
+import java.util.BitSet;
+import org.apache.ignite.ml.math.Vector;
+
+/**
+ * Split node by categorical feature.
+ */
+public class CategoricalSplitNode extends SplitNode {
+    /** Bitset specifying which categories belong to left subregion. */
+    private final BitSet bs;
+
+    /**
+     * Construct categorical split node.
+     *
+     * @param featureIdx Index of feature by which split is done.
+     * @param bs Bitset specifying which categories go to the left subtree.
+     */
+    public CategoricalSplitNode(int featureIdx, BitSet bs) {
+        super(featureIdx);
+        this.bs = bs;
+    }
+
+    /** {@inheritDoc} */
+    @Override public boolean goLeft(Vector v) {
+        return bs.get((int)v.getX(featureIdx));
+    }
+
+    /** {@inheritDoc} */
+    @Override public String toString() {
+        return "CategoricalSplitNode [bs=" + bs + ']';
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/ContinuousSplitNode.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/ContinuousSplitNode.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/ContinuousSplitNode.java
new file mode 100644
index 0000000..285cfcd
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/ContinuousSplitNode.java
@@ -0,0 +1,56 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.nodes;
+
+import org.apache.ignite.ml.math.Vector;
+
+/**
+ * Split node representing split of continuous feature.
+ */
+public class ContinuousSplitNode extends SplitNode {
+    /** Threshold. Values which are less or equal then threshold are assigned to the left subregion. */
+    private final double threshold;
+
+    /**
+     * Construct ContinuousSplitNode by threshold and feature index.
+     *
+     * @param threshold Threshold.
+     * @param featureIdx Feature index.
+     */
+    public ContinuousSplitNode(double threshold, int featureIdx) {
+        super(featureIdx);
+        this.threshold = threshold;
+    }
+
+    /** {@inheritDoc} */
+    @Override public boolean goLeft(Vector v) {
+        return v.getX(featureIdx) <= threshold;
+    }
+
+    /** Threshold. Values which are less or equal then threshold are assigned to the left subregion. */
+    public double threshold() {
+        return threshold;
+    }
+
+    /** {@inheritDoc} */
+    @Override public String toString() {
+        return "ContinuousSplitNode [" +
+            "threshold=" + threshold +
+            ']';
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/DecisionTreeNode.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/DecisionTreeNode.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/DecisionTreeNode.java
new file mode 100644
index 0000000..d31623d
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/DecisionTreeNode.java
@@ -0,0 +1,33 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.nodes;
+
+import org.apache.ignite.ml.math.Vector;
+
+/**
+ * Node of decision tree.
+ */
+public interface DecisionTreeNode {
+    /**
+     * Assign the double value to the given vector.
+     *
+     * @param v Vector.
+     * @return Value assigned to the given vector.
+     */
+    double process(Vector v);
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/Leaf.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/Leaf.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/Leaf.java
new file mode 100644
index 0000000..79b441f
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/Leaf.java
@@ -0,0 +1,49 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.nodes;
+
+import org.apache.ignite.ml.math.Vector;
+
+/**
+ * Terminal node of the decision tree.
+ */
+public class Leaf implements DecisionTreeNode {
+    /**
+     * Value in subregion represented by this node.
+     */
+    private final double val;
+
+    /**
+     * Construct the leaf of decision tree.
+     *
+     * @param val Value in subregion represented by this node.
+     */
+    public Leaf(double val) {
+        this.val = val;
+    }
+
+    /**
+     * Return value in subregion represented by this node.
+     *
+     * @param v Vector.
+     * @return Value in subregion represented by this node.
+     */
+    @Override public double process(Vector v) {
+        return val;
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/SplitNode.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/SplitNode.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/SplitNode.java
new file mode 100644
index 0000000..4c258d1
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/SplitNode.java
@@ -0,0 +1,100 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.nodes;
+
+import org.apache.ignite.ml.math.Vector;
+
+/**
+ * Node in decision tree representing a split.
+ */
+public abstract class SplitNode implements DecisionTreeNode {
+    /** Left subtree. */
+    protected DecisionTreeNode l;
+
+    /** Right subtree. */
+    protected DecisionTreeNode r;
+
+    /** Feature index. */
+    protected final int featureIdx;
+
+    /**
+     * Constructs SplitNode with a given feature index.
+     *
+     * @param featureIdx Feature index.
+     */
+    public SplitNode(int featureIdx) {
+        this.featureIdx = featureIdx;
+    }
+
+    /**
+     * Indicates if the given vector is in left subtree.
+     *
+     * @param v Vector
+     * @return Status of given vector being left subtree.
+     */
+    abstract boolean goLeft(Vector v);
+
+    /**
+     * Left subtree.
+     *
+     * @return Left subtree.
+     */
+    public DecisionTreeNode left() {
+        return l;
+    }
+
+    /**
+     * Right subtree.
+     *
+     * @return Right subtree.
+     */
+    public DecisionTreeNode right() {
+        return r;
+    }
+
+    /**
+     * Set the left subtree.
+     *
+     * @param n left subtree.
+     */
+    public void setLeft(DecisionTreeNode n) {
+        l = n;
+    }
+
+    /**
+     * Set the right subtree.
+     *
+     * @param n right subtree.
+     */
+    public void setRight(DecisionTreeNode n) {
+        r = n;
+    }
+
+    /**
+     * Delegates processing to subtrees.
+     *
+     * @param v Vector.
+     * @return Value assigned to the given vector.
+     */
+    @Override public double process(Vector v) {
+        if (left() != null && goLeft(v))
+            return left().process(v);
+        else
+            return right().process(v);
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/package-info.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/package-info.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/package-info.java
new file mode 100644
index 0000000..d6deb9d
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/nodes/package-info.java
@@ -0,0 +1,22 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * <!-- Package description. -->
+ * Contains classes representing decision tree nodes.
+ */
+package org.apache.ignite.ml.trees.nodes;
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/package-info.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/package-info.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/package-info.java
new file mode 100644
index 0000000..b07ba4a
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/package-info.java
@@ -0,0 +1,22 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * <!-- Package description. -->
+ * Contains decision tree algorithms.
+ */
+package org.apache.ignite.ml.trees;
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/BiIndex.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/BiIndex.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/BiIndex.java
new file mode 100644
index 0000000..0d27c8a
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/BiIndex.java
@@ -0,0 +1,113 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased;
+
+import java.io.Externalizable;
+import java.io.IOException;
+import java.io.ObjectInput;
+import java.io.ObjectOutput;
+import org.apache.ignite.cache.affinity.AffinityKeyMapped;
+
+/**
+ * Class representing a simple index in 2d matrix in the form (row, col).
+ */
+public class BiIndex implements Externalizable {
+    /** Row. */
+    private int row;
+
+    /** Column. */
+    @AffinityKeyMapped
+    private int col;
+
+    /**
+     * No-op constructor for serialization/deserialization.
+     */
+    public BiIndex() {
+        // No-op.
+    }
+
+    /**
+     * Construct BiIndex from row and column.
+     *
+     * @param row Row.
+     * @param col Column.
+     */
+    public BiIndex(int row, int col) {
+        this.row = row;
+        this.col = col;
+    }
+
+    /**
+     * Returns row.
+     *
+     * @return Row.
+     */
+    public int row() {
+        return row;
+    }
+
+    /**
+     * Returns column.
+     *
+     * @return Column.
+     */
+    public int col() {
+        return col;
+    }
+
+    /** {@inheritDoc} */
+    @Override public boolean equals(Object o) {
+        if (this == o)
+            return true;
+        if (o == null || getClass() != o.getClass())
+            return false;
+
+        BiIndex idx = (BiIndex)o;
+
+        if (row != idx.row)
+            return false;
+        return col == idx.col;
+    }
+
+    /** {@inheritDoc} */
+    @Override public int hashCode() {
+        int res = row;
+        res = 31 * res + col;
+        return res;
+    }
+
+    /** {@inheritDoc} */
+    @Override public String toString() {
+        return "BiIndex [" +
+            "row=" + row +
+            ", col=" + col +
+            ']';
+    }
+
+    /** {@inheritDoc} */
+    @Override public void writeExternal(ObjectOutput out) throws IOException {
+        out.writeInt(row);
+        out.writeInt(col);
+    }
+
+    /** {@inheritDoc} */
+    @Override public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
+        row = in.readInt();
+        col = in.readInt();
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/BiIndexedCacheColumnDecisionTreeTrainerInput.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/BiIndexedCacheColumnDecisionTreeTrainerInput.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/BiIndexedCacheColumnDecisionTreeTrainerInput.java
new file mode 100644
index 0000000..04281fb
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/BiIndexedCacheColumnDecisionTreeTrainerInput.java
@@ -0,0 +1,57 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased;
+
+import java.util.Map;
+import java.util.stream.DoubleStream;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.lang.IgniteBiTuple;
+
+/**
+ * Adapter for column decision tree trainer for bi-indexed cache.
+ */
+public class BiIndexedCacheColumnDecisionTreeTrainerInput extends CacheColumnDecisionTreeTrainerInput<BiIndex, Double> {
+    /**
+     * Construct an input for {@link ColumnDecisionTreeTrainer}.
+     *
+     * @param cache Bi-indexed cache.
+     * @param catFeaturesInfo Information about categorical feature in the form (feature index -> number of
+     * categories).
+     * @param samplesCnt Count of samples.
+     * @param featuresCnt Count of features.
+     */
+    public BiIndexedCacheColumnDecisionTreeTrainerInput(IgniteCache<BiIndex, Double> cache,
+        Map<Integer, Integer> catFeaturesInfo, int samplesCnt, int featuresCnt) {
+        super(cache,
+            () -> IntStream.range(0, samplesCnt).mapToObj(s -> new BiIndex(s, featuresCnt)),
+            e -> Stream.of(new IgniteBiTuple<>(e.getKey().row(), e.getValue())),
+            DoubleStream::of,
+            fIdx -> IntStream.range(0, samplesCnt).mapToObj(s -> new BiIndex(s, fIdx)),
+            catFeaturesInfo,
+            featuresCnt,
+            samplesCnt);
+    }
+
+    /** {@inheritDoc} */
+    @Override public Object affinityKey(int idx, Ignite ignite) {
+        return idx;
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/CacheColumnDecisionTreeTrainerInput.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/CacheColumnDecisionTreeTrainerInput.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/CacheColumnDecisionTreeTrainerInput.java
new file mode 100644
index 0000000..9518caf
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/CacheColumnDecisionTreeTrainerInput.java
@@ -0,0 +1,142 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased;
+
+import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.DoubleStream;
+import java.util.stream.Stream;
+import javax.cache.Cache;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.Ignition;
+import org.apache.ignite.internal.processors.cache.CacheEntryImpl;
+import org.apache.ignite.lang.IgniteBiTuple;
+import org.apache.ignite.ml.math.functions.IgniteFunction;
+import org.apache.ignite.ml.math.functions.IgniteSupplier;
+
+/**
+ * Adapter of a given cache to {@see CacheColumnDecisionTreeTrainerInput}
+ *
+ * @param <K> Class of keys of the cache.
+ * @param <V> Class of values of the cache.
+ */
+public abstract class CacheColumnDecisionTreeTrainerInput<K, V> implements ColumnDecisionTreeTrainerInput {
+    /** Supplier of labels key. */
+    private final IgniteSupplier<Stream<K>> labelsKeys;
+
+    /** Count of features. */
+    private final int featuresCnt;
+
+    /** Function which maps feature index to Stream of keys corresponding to this feature index. */
+    private final IgniteFunction<Integer, Stream<K>> keyMapper;
+
+    /** Information about which features are categorical in form of feature index -> number of categories. */
+    private final Map<Integer, Integer> catFeaturesInfo;
+
+    /** Cache name. */
+    private final String cacheName;
+
+    /** Count of samples. */
+    private final int samplesCnt;
+
+    /** Function used for mapping cache values to stream of tuples. */
+    private final IgniteFunction<Cache.Entry<K, V>, Stream<IgniteBiTuple<Integer, Double>>> valuesMapper;
+
+    /**
+     * Function which map value of entry with label key to DoubleStream.
+     * Look at {@code CacheColumnDecisionTreeTrainerInput::labels} for understanding how {@code labelsKeys} and
+     * {@code labelsMapper} interact.
+     */
+    private final IgniteFunction<V, DoubleStream> labelsMapper;
+
+    /**
+     * Constructs input for {@see org.apache.ignite.ml.trees.trainers.columnbased.ColumnDecisionTreeTrainer}.
+     *
+     * @param c Cache.
+     * @param valuesMapper Function for mapping cache entry to stream used by {@link
+     * org.apache.ignite.ml.trees.trainers.columnbased.ColumnDecisionTreeTrainer}.
+     * @param labelsMapper Function used for mapping cache value to labels array.
+     * @param keyMapper Function used for mapping feature index to the cache key.
+     * @param catFeaturesInfo Information about which features are categorical in form of feature index -> number of
+     * categories.
+     * @param featuresCnt Count of features.
+     * @param samplesCnt Count of samples.
+     */
+    // TODO: IGNITE-5724 think about boxing/unboxing
+    public CacheColumnDecisionTreeTrainerInput(IgniteCache<K, V> c,
+        IgniteSupplier<Stream<K>> labelsKeys,
+        IgniteFunction<Cache.Entry<K, V>, Stream<IgniteBiTuple<Integer, Double>>> valuesMapper,
+        IgniteFunction<V, DoubleStream> labelsMapper,
+        IgniteFunction<Integer, Stream<K>> keyMapper,
+        Map<Integer, Integer> catFeaturesInfo,
+        int featuresCnt, int samplesCnt) {
+
+        cacheName = c.getName();
+        this.labelsKeys = labelsKeys;
+        this.valuesMapper = valuesMapper;
+        this.labelsMapper = labelsMapper;
+        this.keyMapper = keyMapper;
+        this.catFeaturesInfo = catFeaturesInfo;
+        this.samplesCnt = samplesCnt;
+        this.featuresCnt = featuresCnt;
+    }
+
+    /** {@inheritDoc} */
+    @Override public Stream<IgniteBiTuple<Integer, Double>> values(int idx) {
+        return cache(Ignition.localIgnite()).getAll(keyMapper.apply(idx).collect(Collectors.toSet())).
+            entrySet().
+            stream().
+            flatMap(ent -> valuesMapper.apply(new CacheEntryImpl<>(ent.getKey(), ent.getValue())));
+    }
+
+    /** {@inheritDoc} */
+    @Override public double[] labels(Ignite ignite) {
+        return labelsKeys.get().map(k -> get(k, ignite)).flatMapToDouble(labelsMapper).toArray();
+    }
+
+    /** {@inheritDoc} */
+    @Override public Map<Integer, Integer> catFeaturesInfo() {
+        return catFeaturesInfo;
+    }
+
+    /** {@inheritDoc} */
+    @Override public int featuresCount() {
+        return featuresCnt;
+    }
+
+    /** {@inheritDoc} */
+    @Override public Object affinityKey(int idx, Ignite ignite) {
+        return ignite.affinity(cacheName).affinityKey(keyMapper.apply(idx));
+    }
+
+    /** */
+    private V get(K k, Ignite ignite) {
+        V res = cache(ignite).localPeek(k);
+
+        if (res == null)
+            res = cache(ignite).get(k);
+
+        return res;
+    }
+
+    /** */
+    private IgniteCache<K, V> cache(Ignite ignite) {
+        return ignite.getOrCreateCache(cacheName);
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/ColumnDecisionTreeTrainer.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/ColumnDecisionTreeTrainer.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/ColumnDecisionTreeTrainer.java
new file mode 100644
index 0000000..32e33f3
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/ColumnDecisionTreeTrainer.java
@@ -0,0 +1,557 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased;
+
+import com.zaxxer.sparsebits.SparseBitSet;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
+import java.util.stream.DoubleStream;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+import javax.cache.Cache;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.Ignition;
+import org.apache.ignite.cache.CachePeekMode;
+import org.apache.ignite.cache.affinity.Affinity;
+import org.apache.ignite.cluster.ClusterNode;
+import org.apache.ignite.internal.processors.cache.CacheEntryImpl;
+import org.apache.ignite.internal.util.typedef.X;
+import org.apache.ignite.lang.IgniteBiTuple;
+import org.apache.ignite.ml.Trainer;
+import org.apache.ignite.ml.math.Vector;
+import org.apache.ignite.ml.math.distributed.CacheUtils;
+import org.apache.ignite.ml.math.functions.Functions;
+import org.apache.ignite.ml.math.functions.IgniteBiFunction;
+import org.apache.ignite.ml.math.functions.IgniteCurriedBiFunction;
+import org.apache.ignite.ml.math.functions.IgniteFunction;
+import org.apache.ignite.ml.math.functions.IgniteSupplier;
+import org.apache.ignite.ml.trees.ContinuousRegionInfo;
+import org.apache.ignite.ml.trees.ContinuousSplitCalculator;
+import org.apache.ignite.ml.trees.models.DecisionTreeModel;
+import org.apache.ignite.ml.trees.nodes.DecisionTreeNode;
+import org.apache.ignite.ml.trees.nodes.Leaf;
+import org.apache.ignite.ml.trees.nodes.SplitNode;
+import org.apache.ignite.ml.trees.trainers.columnbased.caches.ContextCache;
+import org.apache.ignite.ml.trees.trainers.columnbased.caches.FeaturesCache;
+import org.apache.ignite.ml.trees.trainers.columnbased.caches.FeaturesCache.FeatureKey;
+import org.apache.ignite.ml.trees.trainers.columnbased.caches.ProjectionsCache;
+import org.apache.ignite.ml.trees.trainers.columnbased.caches.ProjectionsCache.RegionKey;
+import org.apache.ignite.ml.trees.trainers.columnbased.caches.SplitCache;
+import org.apache.ignite.ml.trees.trainers.columnbased.caches.SplitCache.SplitKey;
+import org.apache.ignite.ml.trees.trainers.columnbased.vectors.FeatureProcessor;
+import org.apache.ignite.ml.trees.trainers.columnbased.vectors.SplitInfo;
+import org.jetbrains.annotations.NotNull;
+
+import static org.apache.ignite.ml.trees.trainers.columnbased.caches.FeaturesCache.getFeatureCacheKey;
+
+/**
+ * This trainer stores observations as columns and features as rows.
+ * Ideas from https://github.com/fabuzaid21/yggdrasil are used here.
+ */
+public class ColumnDecisionTreeTrainer<D extends ContinuousRegionInfo> implements
+    Trainer<DecisionTreeModel, ColumnDecisionTreeTrainerInput> {
+    /**
+     * Function used to assign a value to a region.
+     */
+    private final IgniteFunction<DoubleStream, Double> regCalc;
+
+    /**
+     * Function used to calculate impurity in regions used by categorical features.
+     */
+    private final IgniteFunction<ColumnDecisionTreeTrainerInput, ? extends ContinuousSplitCalculator<D>> continuousCalculatorProvider;
+
+    /**
+     * Categorical calculator provider.
+     **/
+    private final IgniteFunction<ColumnDecisionTreeTrainerInput, IgniteFunction<DoubleStream, Double>> categoricalCalculatorProvider;
+
+    /**
+     * Cache used for storing data for training.
+     */
+    private IgniteCache<RegionKey, List<RegionProjection>> prjsCache;
+
+    /**
+     * Minimal information gain.
+     */
+    private static final double MIN_INFO_GAIN = 1E-10;
+
+    /**
+     * Maximal depth of the decision tree.
+     */
+    private final int maxDepth;
+
+    /**
+     * Size of block which is used for storing regions in cache.
+     */
+    private static final int BLOCK_SIZE = 1 << 4;
+
+    /** Ignite instance. */
+    private final Ignite ignite;
+
+    /**
+     * Construct {@link ColumnDecisionTreeTrainer}.
+     *
+     * @param maxDepth Maximal depth of the decision tree.
+     * @param continuousCalculatorProvider Provider of calculator of splits for region projection on continuous
+     * features.
+     * @param categoricalCalculatorProvider Provider of calculator of splits for region projection on categorical
+     * features.
+     * @param regCalc Function used to assign a value to a region.
+     */
+    public ColumnDecisionTreeTrainer(int maxDepth,
+        IgniteFunction<ColumnDecisionTreeTrainerInput, ? extends ContinuousSplitCalculator<D>> continuousCalculatorProvider,
+        IgniteFunction<ColumnDecisionTreeTrainerInput, IgniteFunction<DoubleStream, Double>> categoricalCalculatorProvider,
+        IgniteFunction<DoubleStream, Double> regCalc,
+        Ignite ignite) {
+        this.maxDepth = maxDepth;
+        this.continuousCalculatorProvider = continuousCalculatorProvider;
+        this.categoricalCalculatorProvider = categoricalCalculatorProvider;
+        this.regCalc = regCalc;
+        this.ignite = ignite;
+    }
+
+    /**
+     * Utility class used to get index of feature by which split is done and split info.
+     */
+    private static class IndexAndSplitInfo {
+        /**
+         * Index of feature by which split is done.
+         */
+        private final int featureIdx;
+
+        /**
+         * Split information.
+         */
+        private final SplitInfo info;
+
+        /**
+         * @param featureIdx Index of feature by which split is done.
+         * @param info Split information.
+         */
+        IndexAndSplitInfo(int featureIdx, SplitInfo info) {
+            this.featureIdx = featureIdx;
+            this.info = info;
+        }
+
+        /** {@inheritDoc} */
+        @Override public String toString() {
+            return "IndexAndSplitInfo [featureIdx=" + featureIdx + ", info=" + info + ']';
+        }
+    }
+
+    /**
+     * Utility class used to build decision tree. Basically it is pointer to leaf node.
+     */
+    private static class TreeTip {
+        /** */
+        private Consumer<DecisionTreeNode> leafSetter;
+
+        /** */
+        private int depth;
+
+        /** */
+        TreeTip(Consumer<DecisionTreeNode> leafSetter, int depth) {
+            this.leafSetter = leafSetter;
+            this.depth = depth;
+        }
+    }
+
+    /**
+     * Utility class used as decision tree root node.
+     */
+    private static class RootNode implements DecisionTreeNode {
+        /** */
+        private DecisionTreeNode s;
+
+        /**
+         * {@inheritDoc}
+         */
+        @Override public double process(Vector v) {
+            return s.process(v);
+        }
+
+        /** */
+        void setSplit(DecisionTreeNode s) {
+            this.s = s;
+        }
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    @Override public DecisionTreeModel train(ColumnDecisionTreeTrainerInput i) {
+        prjsCache = ProjectionsCache.getOrCreate(ignite);
+        IgniteCache<UUID, TrainingContext<D>> ctxtCache = ContextCache.getOrCreate(ignite);
+        SplitCache.getOrCreate(ignite);
+
+        UUID trainingUUID = UUID.randomUUID();
+
+        TrainingContext<D> ct = new TrainingContext<>(i, continuousCalculatorProvider.apply(i), categoricalCalculatorProvider.apply(i), trainingUUID, ignite);
+        ctxtCache.put(trainingUUID, ct);
+
+        CacheUtils.bcast(prjsCache.getName(), ignite, () -> {
+            Ignite ignite = Ignition.localIgnite();
+            IgniteCache<RegionKey, List<RegionProjection>> projCache = ProjectionsCache.getOrCreate(ignite);
+            IgniteCache<FeatureKey, double[]> featuresCache = FeaturesCache.getOrCreate(ignite);
+
+            Affinity<RegionKey> targetAffinity = ignite.affinity(ProjectionsCache.CACHE_NAME);
+
+            ClusterNode locNode = ignite.cluster().localNode();
+
+            Map<FeatureKey, double[]> fm = new ConcurrentHashMap<>();
+            Map<RegionKey, List<RegionProjection>> pm = new ConcurrentHashMap<>();
+
+            targetAffinity.
+                mapKeysToNodes(IntStream.range(0, i.featuresCount()).
+                    mapToObj(idx -> ProjectionsCache.key(idx, 0, i.affinityKey(idx, ignite), trainingUUID)).
+                    collect(Collectors.toSet())).getOrDefault(locNode, Collections.emptyList()).
+                forEach(k -> {
+                    FeatureProcessor vec;
+
+                    int featureIdx = k.featureIdx();
+
+                    IgniteCache<UUID, TrainingContext<D>> ctxCache = ContextCache.getOrCreate(ignite);
+                    TrainingContext ctx = ctxCache.get(trainingUUID);
+                    double[] vals = new double[ctx.labels().length];
+
+                    vec = ctx.featureProcessor(featureIdx);
+                    i.values(featureIdx).forEach(t -> vals[t.get1()] = t.get2());
+
+                    fm.put(getFeatureCacheKey(featureIdx, trainingUUID, i.affinityKey(featureIdx, ignite)), vals);
+
+                    List<RegionProjection> newReg = new ArrayList<>(BLOCK_SIZE);
+                    newReg.add(vec.createInitialRegion(getSamples(i.values(featureIdx), ctx.labels().length), vals, ctx.labels()));
+                    pm.put(k, newReg);
+                });
+
+            featuresCache.putAll(fm);
+            projCache.putAll(pm);
+
+            return null;
+        });
+
+        return doTrain(i, trainingUUID);
+    }
+
+    /**
+     * Get samples array.
+     *
+     * @param values Stream of tuples in the form of (index, value).
+     * @param size size of stream.
+     * @return Samples array.
+     */
+    private Integer[] getSamples(Stream<IgniteBiTuple<Integer, Double>> values, int size) {
+        Integer[] res = new Integer[size];
+
+        values.forEach(v -> res[v.get1()] = v.get1());
+
+        return res;
+    }
+
+    /** */
+    @NotNull
+    private DecisionTreeModel doTrain(ColumnDecisionTreeTrainerInput input, UUID uuid) {
+        RootNode root = new RootNode();
+
+        // List containing setters of leaves of the tree.
+        List<TreeTip> tips = new LinkedList<>();
+        tips.add(new TreeTip(root::setSplit, 0));
+
+        int curDepth = 0;
+        int regsCnt = 1;
+
+        int featuresCnt = input.featuresCount();
+        IntStream.range(0, featuresCnt).mapToObj(fIdx -> SplitCache.key(fIdx, input.affinityKey(fIdx, ignite), uuid)).
+            forEach(k -> SplitCache.getOrCreate(ignite).put(k, new IgniteBiTuple<>(0, 0.0)));
+        updateSplitCache(0, regsCnt, featuresCnt, ig -> i -> input.affinityKey(i, ig), uuid);
+
+        // TODO: IGNITE-5893 Currently if the best split makes tree deeper than max depth process will be terminated, but actually we should
+        // only stop when *any* improving split makes tree deeper than max depth. Can be fixed if we will store which
+        // regions cannot be split more and split only those that can.
+        while (true) {
+            long before = System.currentTimeMillis();
+
+            IgniteBiTuple<Integer, IgniteBiTuple<Integer, Double>> b = findBestSplitIndexForFeatures(featuresCnt, input::affinityKey, uuid);
+
+            long findBestRegIdx = System.currentTimeMillis() - before;
+
+            Integer bestFeatureIdx = b.get1();
+
+            Integer regIdx = b.get2().get1();
+            Double bestInfoGain = b.get2().get2();
+
+            if (regIdx >= 0 && bestInfoGain > MIN_INFO_GAIN) {
+                before = System.currentTimeMillis();
+
+                SplitInfo bi = ignite.compute().affinityCall(ProjectionsCache.CACHE_NAME,
+                    input.affinityKey(bestFeatureIdx, ignite),
+                    () -> {
+                        TrainingContext<ContinuousRegionInfo> ctx = ContextCache.getOrCreate(ignite).get(uuid);
+                        Ignite ignite = Ignition.localIgnite();
+                        RegionKey key = ProjectionsCache.key(bestFeatureIdx,
+                            regIdx / BLOCK_SIZE,
+                            input.affinityKey(bestFeatureIdx, Ignition.localIgnite()),
+                            uuid);
+                        RegionProjection reg = ProjectionsCache.getOrCreate(ignite).localPeek(key).get(regIdx % BLOCK_SIZE);
+                        return ctx.featureProcessor(bestFeatureIdx).findBestSplit(reg, ctx.values(bestFeatureIdx, ignite), ctx.labels(), regIdx);
+                    });
+
+                long findBestSplit = System.currentTimeMillis() - before;
+
+                IndexAndSplitInfo best = new IndexAndSplitInfo(bestFeatureIdx, bi);
+
+                regsCnt++;
+
+                X.println(">>> Globally best: " + best.info + " idx time: " + findBestRegIdx + ", calculate best: " + findBestSplit + " fi: " + best.featureIdx + ", regs: " + regsCnt);
+                // Request bitset for split region.
+                int ind = best.info.regionIndex();
+
+                SparseBitSet bs = ignite.compute().affinityCall(ProjectionsCache.CACHE_NAME,
+                    input.affinityKey(bestFeatureIdx, ignite),
+                    () -> {
+                        Ignite ignite = Ignition.localIgnite();
+                        IgniteCache<FeatureKey, double[]> featuresCache = FeaturesCache.getOrCreate(ignite);
+                        IgniteCache<UUID, TrainingContext<D>> ctxCache = ContextCache.getOrCreate(ignite);
+                        TrainingContext ctx = ctxCache.localPeek(uuid);
+
+                        double[] values = featuresCache.localPeek(getFeatureCacheKey(bestFeatureIdx, uuid, input.affinityKey(bestFeatureIdx, Ignition.localIgnite())));
+                        RegionKey key = ProjectionsCache.key(bestFeatureIdx,
+                            regIdx / BLOCK_SIZE,
+                            input.affinityKey(bestFeatureIdx, Ignition.localIgnite()),
+                            uuid);
+                        RegionProjection reg = ProjectionsCache.getOrCreate(ignite).localPeek(key).get(regIdx % BLOCK_SIZE);
+                        return ctx.featureProcessor(bestFeatureIdx).calculateOwnershipBitSet(reg, values, best.info);
+
+                    });
+
+                SplitNode sn = best.info.createSplitNode(best.featureIdx);
+
+                TreeTip tipToSplit = tips.get(ind);
+                tipToSplit.leafSetter.accept(sn);
+                tipToSplit.leafSetter = sn::setLeft;
+                int d = tipToSplit.depth++;
+                tips.add(new TreeTip(sn::setRight, d));
+
+                if (d > curDepth) {
+                    curDepth = d;
+                    X.println(">>> Depth: " + curDepth);
+                    X.println(">>> Cache size: " + prjsCache.size(CachePeekMode.PRIMARY));
+                }
+
+                before = System.currentTimeMillis();
+                // Perform split on all feature vectors.
+                IgniteSupplier<Set<RegionKey>> bestRegsKeys = () -> IntStream.range(0, featuresCnt).
+                    mapToObj(fIdx -> ProjectionsCache.key(fIdx, ind / BLOCK_SIZE, input.affinityKey(fIdx, Ignition.localIgnite()), uuid)).
+                    collect(Collectors.toSet());
+
+                int rc = regsCnt;
+
+                // Perform split.
+                CacheUtils.update(prjsCache.getName(), ignite,
+                    (Ignite ign, Cache.Entry<RegionKey, List<RegionProjection>> e) -> {
+                        RegionKey k = e.getKey();
+
+                        List<RegionProjection> leftBlock = e.getValue();
+
+                        int fIdx = k.featureIdx();
+                        int idxInBlock = ind % BLOCK_SIZE;
+
+                        IgniteCache<UUID, TrainingContext<D>> ctxCache = ContextCache.getOrCreate(ign);
+                        TrainingContext<D> ctx = ctxCache.get(uuid);
+
+                        RegionProjection targetRegProj = leftBlock.get(idxInBlock);
+
+                        IgniteBiTuple<RegionProjection, RegionProjection> regs = ctx.
+                            performSplit(input, bs, fIdx, best.featureIdx, targetRegProj, best.info.leftData(), best.info.rightData(), ign);
+
+                        RegionProjection left = regs.get1();
+                        RegionProjection right = regs.get2();
+
+                        leftBlock.set(idxInBlock, left);
+                        RegionKey rightKey = ProjectionsCache.key(fIdx, (rc - 1) / BLOCK_SIZE, input.affinityKey(fIdx, ign), uuid);
+
+                        IgniteCache<RegionKey, List<RegionProjection>> c = ProjectionsCache.getOrCreate(ign);
+
+                        List<RegionProjection> rightBlock = rightKey.equals(k) ? leftBlock : c.localPeek(rightKey);
+
+                        if (rightBlock == null) {
+                            List<RegionProjection> newBlock = new ArrayList<>(BLOCK_SIZE);
+                            newBlock.add(right);
+                            return Stream.of(new CacheEntryImpl<>(k, leftBlock), new CacheEntryImpl<>(rightKey, newBlock));
+                        }
+                        else {
+                            rightBlock.add(right);
+                            return rightBlock.equals(k) ?
+                                Stream.of(new CacheEntryImpl<>(k, leftBlock)) :
+                                Stream.of(new CacheEntryImpl<>(k, leftBlock), new CacheEntryImpl<>(rightKey, rightBlock));
+                        }
+                    },
+                    bestRegsKeys);
+
+                X.println(">>> Update of projs cache took " + (System.currentTimeMillis() - before));
+
+                before = System.currentTimeMillis();
+
+                updateSplitCache(ind, rc, featuresCnt, ig -> i -> input.affinityKey(i, ig), uuid);
+
+                X.println(">>> Update of split cache took " + (System.currentTimeMillis() - before));
+            }
+            else {
+                X.println(">>> Best feature index: " + bestFeatureIdx + ", best infoGain " + bestInfoGain);
+                break;
+            }
+        }
+
+        int rc = regsCnt;
+
+        IgniteSupplier<Iterable<Cache.Entry<RegionKey, List<RegionProjection>>>> featZeroRegs = () -> {
+            IgniteCache<RegionKey, List<RegionProjection>> projsCache = ProjectionsCache.getOrCreate(Ignition.localIgnite());
+
+            return () -> IntStream.range(0, (rc - 1) / BLOCK_SIZE + 1).
+                mapToObj(rBIdx -> ProjectionsCache.key(0, rBIdx, input.affinityKey(0, Ignition.localIgnite()), uuid)).
+                map(k -> (Cache.Entry<RegionKey, List<RegionProjection>>)new CacheEntryImpl<>(k, projsCache.localPeek(k))).iterator();
+        };
+
+        Map<Integer, Double> vals = CacheUtils.reduce(prjsCache.getName(), ignite,
+            (TrainingContext ctx, Cache.Entry<RegionKey, List<RegionProjection>> e, Map<Integer, Double> m) -> {
+                int regBlockIdx = e.getKey().regionBlockIndex();
+
+                if (e.getValue() != null) {
+                    for (int i = 0; i < e.getValue().size(); i++) {
+                        int regIdx = regBlockIdx * BLOCK_SIZE + i;
+                        RegionProjection reg = e.getValue().get(i);
+
+                        Double res = regCalc.apply(Arrays.stream(reg.sampleIndexes()).mapToDouble(s -> ctx.labels()[s]));
+                        m.put(regIdx, res);
+                    }
+                }
+
+                return m;
+            },
+            () -> ContextCache.getOrCreate(Ignition.localIgnite()).get(uuid),
+            featZeroRegs,
+            (infos, infos2) -> {
+                Map<Integer, Double> res = new HashMap<>();
+                res.putAll(infos);
+                res.putAll(infos2);
+                return res;
+            },
+            HashMap::new
+        );
+
+        int i = 0;
+        for (TreeTip tip : tips) {
+            tip.leafSetter.accept(new Leaf(vals.get(i)));
+            i++;
+        }
+
+        ProjectionsCache.clear(featuresCnt, rc, input::affinityKey, uuid, ignite);
+        ContextCache.getOrCreate(ignite).remove(uuid);
+        FeaturesCache.clear(featuresCnt, input::affinityKey, uuid, ignite);
+        SplitCache.clear(featuresCnt, input::affinityKey, uuid, ignite);
+
+        return new DecisionTreeModel(root.s);
+    }
+
+    /**
+     * Find the best split in the form (feature index, (index of region with the best split, impurity of region with the
+     * best split)).
+     *
+     * @param featuresCnt Count of features.
+     * @param affinity Affinity function.
+     * @param trainingUUID UUID of training.
+     * @return Best split in the form (feature index, (index of region with the best split, impurity of region with the
+     * best split)).
+     */
+    private IgniteBiTuple<Integer, IgniteBiTuple<Integer, Double>> findBestSplitIndexForFeatures(int featuresCnt,
+        IgniteBiFunction<Integer, Ignite, Object> affinity,
+        UUID trainingUUID) {
+        Set<Integer> featureIndexes = IntStream.range(0, featuresCnt).boxed().collect(Collectors.toSet());
+
+        return CacheUtils.reduce(SplitCache.CACHE_NAME, ignite,
+            (Object ctx, Cache.Entry<SplitKey, IgniteBiTuple<Integer, Double>> e, IgniteBiTuple<Integer, IgniteBiTuple<Integer, Double>> r) ->
+                Functions.MAX_GENERIC(new IgniteBiTuple<>(e.getKey().featureIdx(), e.getValue()), r, comparator()),
+            () -> null,
+            () -> SplitCache.localEntries(featureIndexes, affinity, trainingUUID),
+            (i1, i2) -> Functions.MAX_GENERIC(i1, i2, Comparator.comparingDouble(bt -> bt.get2().get2())),
+            () -> new IgniteBiTuple<>(-1, new IgniteBiTuple<>(-1, Double.NEGATIVE_INFINITY))
+        );
+    }
+
+    /** */
+    private static Comparator<IgniteBiTuple<Integer, IgniteBiTuple<Integer, Double>>> comparator() {
+        return Comparator.comparingDouble(bt -> bt != null && bt.get2() != null ? bt.get2().get2() : Double.NEGATIVE_INFINITY);
+    }
+
+    /**
+     * Update split cache.
+     *
+     * @param lastSplitRegionIdx Index of region which had last best split.
+     * @param regsCnt Count of regions.
+     * @param featuresCnt Count of features.
+     * @param affinity Affinity function.
+     * @param trainingUUID UUID of current training.
+     */
+    private void updateSplitCache(int lastSplitRegionIdx, int regsCnt, int featuresCnt,
+        IgniteCurriedBiFunction<Ignite, Integer, Object> affinity,
+        UUID trainingUUID) {
+        CacheUtils.update(SplitCache.CACHE_NAME, ignite,
+            (Ignite ign, Cache.Entry<SplitKey, IgniteBiTuple<Integer, Double>> e) -> {
+                Integer bestRegIdx = e.getValue().get1();
+                int fIdx = e.getKey().featureIdx();
+                TrainingContext ctx = ContextCache.getOrCreate(ign).get(trainingUUID);
+
+                Map<Integer, RegionProjection> toCompare;
+
+                // Fully recalculate best.
+                if (bestRegIdx == lastSplitRegionIdx)
+                    toCompare = ProjectionsCache.projectionsOfFeature(fIdx, maxDepth, regsCnt, BLOCK_SIZE, affinity.apply(ign), trainingUUID, ign);
+                    // Just compare previous best and two regions which are produced by split.
+                else
+                    toCompare = ProjectionsCache.projectionsOfRegions(fIdx, maxDepth,
+                        IntStream.of(bestRegIdx, lastSplitRegionIdx, regsCnt - 1), BLOCK_SIZE, affinity.apply(ign), trainingUUID, ign);
+
+                double[] values = ctx.values(fIdx, ign);
+                double[] labels = ctx.labels();
+
+                IgniteBiTuple<Integer, Double> max = toCompare.entrySet().stream().
+                    map(ent -> {
+                        SplitInfo bestSplit = ctx.featureProcessor(fIdx).findBestSplit(ent.getValue(), values, labels, ent.getKey());
+                        return new IgniteBiTuple<>(ent.getKey(), bestSplit != null ? bestSplit.infoGain() : Double.NEGATIVE_INFINITY);
+                    }).
+                    max(Comparator.comparingDouble(IgniteBiTuple::get2)).
+                    get();
+
+                return Stream.of(new CacheEntryImpl<>(e.getKey(), max));
+            },
+            () -> IntStream.range(0, featuresCnt).mapToObj(fIdx -> SplitCache.key(fIdx, affinity.apply(ignite).apply(fIdx), trainingUUID)).collect(Collectors.toSet())
+        );
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/ColumnDecisionTreeTrainerInput.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/ColumnDecisionTreeTrainerInput.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/ColumnDecisionTreeTrainerInput.java
new file mode 100644
index 0000000..94331f7
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/ColumnDecisionTreeTrainerInput.java
@@ -0,0 +1,55 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased;
+
+import java.util.Map;
+import java.util.stream.Stream;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.lang.IgniteBiTuple;
+
+/**
+ * Input for {@see ColumnDecisionTreeTrainer}.
+ */
+public interface ColumnDecisionTreeTrainerInput {
+    /**
+     * Projection of data on feature with the given index.
+     *
+     * @param idx Feature index.
+     * @return Projection of data on feature with the given index.
+     */
+    Stream<IgniteBiTuple<Integer, Double>> values(int idx);
+
+    /**
+     * Labels.
+     *
+     * @param ignite Ignite instance.
+     */
+    double[] labels(Ignite ignite);
+
+    /** Information about which features are categorical in the form of feature index -> number of categories. */
+    Map<Integer, Integer> catFeaturesInfo();
+
+    /** Number of features. */
+    int featuresCount();
+
+    /**
+     * Get affinity key for the given column index.
+     * Affinity key should be pure-functionally dependent from idx.
+     */
+    Object affinityKey(int idx, Ignite ignite);
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/MatrixColumnDecisionTreeTrainerInput.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/MatrixColumnDecisionTreeTrainerInput.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/MatrixColumnDecisionTreeTrainerInput.java
new file mode 100644
index 0000000..9a11902
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/MatrixColumnDecisionTreeTrainerInput.java
@@ -0,0 +1,82 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.stream.DoubleStream;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+import javax.cache.Cache;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.lang.IgniteBiTuple;
+import org.apache.ignite.ml.math.distributed.keys.RowColMatrixKey;
+import org.apache.ignite.ml.math.distributed.keys.impl.SparseMatrixKey;
+import org.apache.ignite.ml.math.functions.IgniteFunction;
+import org.apache.ignite.ml.math.impls.matrix.SparseDistributedMatrix;
+import org.apache.ignite.ml.math.impls.storage.matrix.SparseDistributedMatrixStorage;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Adapter of SparseDistributedMatrix to ColumnDecisionTreeTrainerInput.
+ * Sparse SparseDistributedMatrix should be in {@see org.apache.ignite.ml.math.StorageConstants#COLUMN_STORAGE_MODE} and
+ * should contain samples in rows last position in row being label of this sample.
+ */
+public class MatrixColumnDecisionTreeTrainerInput extends CacheColumnDecisionTreeTrainerInput<RowColMatrixKey, Map<Integer, Double>> {
+    /**
+     * @param m Sparse SparseDistributedMatrix should be in {@see org.apache.ignite.ml.math.StorageConstants#COLUMN_STORAGE_MODE}
+     * containing samples in rows last position in row being label of this sample.
+     * @param catFeaturesInfo Information about which features are categorical in form of feature index -> number of
+     * categories.
+     */
+    public MatrixColumnDecisionTreeTrainerInput(SparseDistributedMatrix m, Map<Integer, Integer> catFeaturesInfo) {
+        super(((SparseDistributedMatrixStorage)m.getStorage()).cache(),
+            () -> Stream.of(new SparseMatrixKey(m.columnSize() - 1, m.getUUID(), m.columnSize() - 1)),
+            valuesMapper(m),
+            labels(m),
+            keyMapper(m),
+            catFeaturesInfo,
+            m.columnSize() - 1,
+            m.rowSize());
+    }
+
+    /** Values mapper. See {@link CacheColumnDecisionTreeTrainerInput#valuesMapper} */
+    @NotNull
+    private static IgniteFunction<Cache.Entry<RowColMatrixKey, Map<Integer, Double>>, Stream<IgniteBiTuple<Integer, Double>>> valuesMapper(
+        SparseDistributedMatrix m) {
+        return ent -> {
+            Map<Integer, Double> map = ent.getValue() != null ? ent.getValue() : new HashMap<>();
+            return IntStream.range(0, m.rowSize()).mapToObj(k -> new IgniteBiTuple<>(k, map.getOrDefault(k, 0.0)));
+        };
+    }
+
+    /** Key mapper. See {@link CacheColumnDecisionTreeTrainerInput#keyMapper} */
+    @NotNull private static IgniteFunction<Integer, Stream<RowColMatrixKey>> keyMapper(SparseDistributedMatrix m) {
+        return i -> Stream.of(new SparseMatrixKey(i, ((SparseDistributedMatrixStorage)m.getStorage()).getUUID(), i));
+    }
+
+    /** Labels mapper. See {@link CacheColumnDecisionTreeTrainerInput#labelsMapper} */
+    @NotNull private static IgniteFunction<Map<Integer, Double>, DoubleStream> labels(SparseDistributedMatrix m) {
+        return mp -> IntStream.range(0, m.rowSize()).mapToDouble(k -> mp.getOrDefault(k, 0.0));
+    }
+
+    /** {@inheritDoc} */
+    @Override public Object affinityKey(int idx, Ignite ignite) {
+        return idx;
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/RegionProjection.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/RegionProjection.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/RegionProjection.java
new file mode 100644
index 0000000..e95f57b
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/RegionProjection.java
@@ -0,0 +1,109 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased;
+
+import java.io.Externalizable;
+import java.io.IOException;
+import java.io.ObjectInput;
+import java.io.ObjectOutput;
+import org.apache.ignite.ml.trees.RegionInfo;
+
+/**
+ * Projection of region on given feature.
+ *
+ * @param <D> Data of region.
+ */
+public class RegionProjection<D extends RegionInfo> implements Externalizable {
+    /** Samples projections. */
+    protected Integer[] sampleIndexes;
+
+    /** Region data */
+    protected D data;
+
+    /** Depth of this region. */
+    protected int depth;
+
+    /**
+     * @param sampleIndexes Samples indexes.
+     * @param data Region data.
+     * @param depth Depth of this region.
+     */
+    public RegionProjection(Integer[] sampleIndexes, D data, int depth) {
+        this.data = data;
+        this.depth = depth;
+        this.sampleIndexes = sampleIndexes;
+    }
+
+    /**
+     * No-op constructor used for serialization/deserialization.
+     */
+    public RegionProjection() {
+        // No-op.
+    }
+
+    /**
+     * Get samples indexes.
+     *
+     * @return Samples indexes.
+     */
+    public Integer[] sampleIndexes() {
+        return sampleIndexes;
+    }
+
+    /**
+     * Get region data.
+     *
+     * @return Region data.
+     */
+    public D data() {
+        return data;
+    }
+
+    /**
+     * Get region depth.
+     *
+     * @return Region depth.
+     */
+    public int depth() {
+        return depth;
+    }
+
+    /** {@inheritDoc} */
+    @Override public void writeExternal(ObjectOutput out) throws IOException {
+        out.writeInt(sampleIndexes.length);
+
+        for (Integer sampleIndex : sampleIndexes)
+            out.writeInt(sampleIndex);
+
+        out.writeObject(data);
+        out.writeInt(depth);
+    }
+
+    /** {@inheritDoc} */
+    @Override public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
+        int size = in.readInt();
+
+        sampleIndexes = new Integer[size];
+
+        for (int i = 0; i < size; i++)
+            sampleIndexes[i] = in.readInt();
+
+        data = (D)in.readObject();
+        depth = in.readInt();
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/TrainingContext.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/TrainingContext.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/TrainingContext.java
new file mode 100644
index 0000000..6415dab
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/TrainingContext.java
@@ -0,0 +1,166 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased;
+
+import com.zaxxer.sparsebits.SparseBitSet;
+import java.util.Map;
+import java.util.UUID;
+import java.util.stream.DoubleStream;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.Ignition;
+import org.apache.ignite.lang.IgniteBiTuple;
+import org.apache.ignite.ml.math.functions.IgniteFunction;
+import org.apache.ignite.ml.trees.ContinuousRegionInfo;
+import org.apache.ignite.ml.trees.ContinuousSplitCalculator;
+import org.apache.ignite.ml.trees.RegionInfo;
+import org.apache.ignite.ml.trees.trainers.columnbased.caches.FeaturesCache;
+import org.apache.ignite.ml.trees.trainers.columnbased.vectors.CategoricalFeatureProcessor;
+import org.apache.ignite.ml.trees.trainers.columnbased.vectors.ContinuousFeatureProcessor;
+import org.apache.ignite.ml.trees.trainers.columnbased.vectors.FeatureProcessor;
+
+import static org.apache.ignite.ml.trees.trainers.columnbased.caches.FeaturesCache.COLUMN_DECISION_TREE_TRAINER_FEATURES_CACHE_NAME;
+
+/**
+ * Context of training with {@link ColumnDecisionTreeTrainer}.
+ *
+ * @param <D> Class for storing of information used in calculation of impurity of continuous feature region.
+ */
+public class TrainingContext<D extends ContinuousRegionInfo> {
+    /** Input for training with {@link ColumnDecisionTreeTrainer}. */
+    private final ColumnDecisionTreeTrainerInput input;
+
+    /** Labels. */
+    private final double[] labels;
+
+    /** Calculator used for finding splits of region of continuous features. */
+    private final ContinuousSplitCalculator<D> continuousSplitCalculator;
+
+    /** Calculator used for finding splits of region of categorical feature. */
+    private final IgniteFunction<DoubleStream, Double> categoricalSplitCalculator;
+
+    /** UUID of current training. */
+    private final UUID trainingUUID;
+
+    /**
+     * Construct context for training with {@link ColumnDecisionTreeTrainer}.
+     *
+     * @param input Input for training.
+     * @param continuousSplitCalculator Calculator used for calculations of splits of continuous features regions.
+     * @param categoricalSplitCalculator Calculator used for calculations of splits of categorical features regions.
+     * @param trainingUUID UUID of the current training.
+     * @param ignite Ignite instance.
+     */
+    public TrainingContext(ColumnDecisionTreeTrainerInput input,
+        ContinuousSplitCalculator<D> continuousSplitCalculator,
+        IgniteFunction<DoubleStream, Double> categoricalSplitCalculator,
+        UUID trainingUUID,
+        Ignite ignite) {
+        this.input = input;
+        this.labels = input.labels(ignite);
+        this.continuousSplitCalculator = continuousSplitCalculator;
+        this.categoricalSplitCalculator = categoricalSplitCalculator;
+        this.trainingUUID = trainingUUID;
+    }
+
+    /**
+     * Get processor used for calculating splits of categorical features.
+     *
+     * @param catsCnt Count of categories.
+     * @return Processor used for calculating splits of categorical features.
+     */
+    public CategoricalFeatureProcessor categoricalFeatureProcessor(int catsCnt) {
+        return new CategoricalFeatureProcessor(categoricalSplitCalculator, catsCnt);
+    }
+
+    /**
+     * Get processor used for calculating splits of continuous features.
+     *
+     * @return Processor used for calculating splits of continuous features.
+     */
+    public ContinuousFeatureProcessor<D> continuousFeatureProcessor() {
+        return new ContinuousFeatureProcessor<>(continuousSplitCalculator);
+    }
+
+    /**
+     * Get labels.
+     *
+     * @return Labels.
+     */
+    public double[] labels() {
+        return labels;
+    }
+
+    /**
+     * Get values of feature with given index.
+     *
+     * @param featIdx Feature index.
+     * @param ignite Ignite instance.
+     * @return Values of feature with given index.
+     */
+    public double[] values(int featIdx, Ignite ignite) {
+        IgniteCache<FeaturesCache.FeatureKey, double[]> featuresCache = ignite.getOrCreateCache(COLUMN_DECISION_TREE_TRAINER_FEATURES_CACHE_NAME);
+        return featuresCache.localPeek(FeaturesCache.getFeatureCacheKey(featIdx, trainingUUID, input.affinityKey(featIdx, ignite)));
+    }
+
+    /**
+     * Perform best split on the given region projection.
+     *
+     * @param input Input of {@link ColumnDecisionTreeTrainer} performing split.
+     * @param bitSet Bit set specifying split.
+     * @param targetFeatIdx Index of feature for performing split.
+     * @param bestFeatIdx Index of feature with best split.
+     * @param targetRegionPrj Projection of region to split on feature with index {@code featureIdx}.
+     * @param leftData Data of left region of split.
+     * @param rightData Data of right region of split.
+     * @param ignite Ignite instance.
+     * @return Perform best split on the given region projection.
+     */
+    public IgniteBiTuple<RegionProjection, RegionProjection> performSplit(ColumnDecisionTreeTrainerInput input,
+        SparseBitSet bitSet, int targetFeatIdx, int bestFeatIdx, RegionProjection targetRegionPrj, RegionInfo leftData,
+        RegionInfo rightData, Ignite ignite) {
+
+        Map<Integer, Integer> catFeaturesInfo = input.catFeaturesInfo();
+
+        if (!catFeaturesInfo.containsKey(targetFeatIdx) && !catFeaturesInfo.containsKey(bestFeatIdx))
+            return continuousFeatureProcessor().performSplit(bitSet, targetRegionPrj, (D)leftData, (D)rightData);
+        else if (catFeaturesInfo.containsKey(targetFeatIdx))
+            return categoricalFeatureProcessor(catFeaturesInfo.get(targetFeatIdx)).performSplitGeneric(bitSet, values(targetFeatIdx, ignite), targetRegionPrj, leftData, rightData);
+        return continuousFeatureProcessor().performSplitGeneric(bitSet, labels, targetRegionPrj, leftData, rightData);
+    }
+
+    /**
+     * Processor used for calculating splits for feature with the given index.
+     *
+     * @param featureIdx Index of feature to process.
+     * @return Processor used for calculating splits for feature with the given index.
+     */
+    public FeatureProcessor featureProcessor(int featureIdx) {
+        return input.catFeaturesInfo().containsKey(featureIdx) ? categoricalFeatureProcessor(input.catFeaturesInfo().get(featureIdx)) : continuousFeatureProcessor();
+    }
+
+    /**
+     * Shortcut for affinity key.
+     *
+     * @param idx Feature index.
+     * @return Affinity key.
+     */
+    public Object affinityKey(int idx) {
+        return input.affinityKey(idx, Ignition.localIgnite());
+    }
+}

http://git-wip-us.apache.org/repos/asf/ignite/blob/db7697b1/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/caches/ContextCache.java
----------------------------------------------------------------------
diff --git a/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/caches/ContextCache.java b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/caches/ContextCache.java
new file mode 100644
index 0000000..51ea359
--- /dev/null
+++ b/modules/ml/src/main/java/org/apache/ignite/ml/trees/trainers/columnbased/caches/ContextCache.java
@@ -0,0 +1,68 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.ignite.ml.trees.trainers.columnbased.caches;
+
+import java.util.UUID;
+import org.apache.ignite.Ignite;
+import org.apache.ignite.IgniteCache;
+import org.apache.ignite.cache.CacheAtomicityMode;
+import org.apache.ignite.cache.CacheMode;
+import org.apache.ignite.cache.CacheWriteSynchronizationMode;
+import org.apache.ignite.configuration.CacheConfiguration;
+import org.apache.ignite.ml.trees.ContinuousRegionInfo;
+import org.apache.ignite.ml.trees.trainers.columnbased.ColumnDecisionTreeTrainer;
+import org.apache.ignite.ml.trees.trainers.columnbased.TrainingContext;
+
+/**
+ * Class for operations related to cache containing training context for {@link ColumnDecisionTreeTrainer}.
+ */
+public class ContextCache {
+    /**
+     * Name of cache containing training context for {@link ColumnDecisionTreeTrainer}.
+     */
+    public static final String COLUMN_DECISION_TREE_TRAINER_CONTEXT_CACHE_NAME = "COLUMN_DECISION_TREE_TRAINER_CONTEXT_CACHE_NAME";
+
+    /**
+     * Get or create cache for training context.
+     *
+     * @param ignite Ignite instance.
+     * @param <D> Class storing information about continuous regions.
+     * @return Cache for training context.
+     */
+    public static <D extends ContinuousRegionInfo> IgniteCache<UUID, TrainingContext<D>> getOrCreate(Ignite ignite) {
+        CacheConfiguration<UUID, TrainingContext<D>> cfg = new CacheConfiguration<>();
+
+        cfg.setWriteSynchronizationMode(CacheWriteSynchronizationMode.FULL_SYNC);
+
+        cfg.setAtomicityMode(CacheAtomicityMode.ATOMIC);
+
+        cfg.setEvictionPolicy(null);
+
+        cfg.setCopyOnRead(false);
+
+        cfg.setCacheMode(CacheMode.REPLICATED);
+
+        cfg.setOnheapCacheEnabled(true);
+
+        cfg.setReadFromBackup(true);
+
+        cfg.setName(COLUMN_DECISION_TREE_TRAINER_CONTEXT_CACHE_NAME);
+
+        return ignite.getOrCreateCache(cfg);
+    }
+}