[GitHub] [flink] becketqin commented on a change in pull request #8631: [FLINK-12745][ml] add sparse and dense vector class, and dense matrix class with basic operations.

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becketqin commented on a change in pull request #8631: [FLINK-12745][ml] add sparse and dense vector class, and dense matrix class with basic operations.
URL: https://github.com/apache/flink/pull/8631#discussion_r309448144
 
 

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 File path: flink-ml-parent/flink-ml-lib/src/main/java/org/apache/flink/ml/common/matrix/DenseVector.java
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 @@ -0,0 +1,508 @@
+/*
+ * 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.flink.ml.common.matrix;
+
+import org.apache.commons.lang3.StringUtils;
+
+import java.util.Random;
+
+/**
+ * A dense vector represented by a values array.
+ */
+public class DenseVector extends Vector {
+
+	/**
+	 * Vector data.
+	 */
+	double[] data;
+
+	public DenseVector() {
+		this(0);
+	}
+
+	public DenseVector(int n) {
+		this.data = new double[n];
+	}
+
+	public DenseVector(double[] data) {
+		this.data = data.clone();
+	}
+
+	@Override
+	public DenseVector clone() {
+		DenseVector c = new DenseVector();
+		c.setData(this.data.clone());
+		return c;
+	}
+
+	public static DenseVector ones(int n) {
+		DenseVector r = new DenseVector(n);
+		for (int i = 0; i < r.data.length; i++) {
+			r.data[i] = 1.0;
+		}
+		return r;
+	}
+
+	public static DenseVector zeros(int n) {
+		DenseVector r = new DenseVector(n);
+		for (int i = 0; i < r.data.length; i++) {
+			r.data[i] = 0.0;
+		}
+		return r;
+	}
+
+	public static DenseVector rand(int n) {
+		Random random = new Random();
+		DenseVector v = new DenseVector(n);
+		for (int i = 0; i < n; i++) {
+			v.set(i, random.nextDouble());
+		}
+		return v;
+	}
+
+	@Override
+	public String toString() {
+		StringBuilder sbd = new StringBuilder();
+
+		for (int i = 0; i < data.length; i++) {
+			sbd.append(data[i]);
+			if (i < data.length - 1) {
+				sbd.append(",");
+			}
+		}
+
+		return sbd.toString();
+	}
+
+	@Override
+	public int size() {
+		return data.length;
+	}
+
+	@Override
+	public double get(int i) {
+		return data[i];
+	}
+
+	@Override
+	public void set(int i, double d) {
+		data[i] = d;
+	}
+
+	@Override
+	public void add(int i, double d) {
+		data[i] += d;
+	}
+
+	@Override
+	public double normL1() {
+		double d = 0;
+		for (double t : data) {
+			d += Math.abs(t);
+		}
+		return d;
+	}
+
+	@Override
+	public double normL2() {
+		double d = 0;
+		for (double t : data) {
+			d += t * t;
+		}
+		return Math.sqrt(d);
+	}
+
+	@Override
+	public double normL2Square() {
+		double d = 0;
+		for (double t : data) {
+			d += t * t;
+		}
+		return d;
+	}
+
+	@Override
+	public double normInf() {
+		double d = 0;
+		for (double t : data) {
+			d = Math.max(Math.abs(t), d);
+		}
+		return d;
+	}
+
+	@Override
+	public DenseVector slice(int[] indices) {
+		double[] values = new double[indices.length];
+		for (int i = 0; i < indices.length; ++i) {
+			if (indices[i] >= data.length) {
+				throw new RuntimeException("Index is larger than vector size.");
+			}
+			values[i] = data[indices[i]];
+		}
+		return new DenseVector(values);
+	}
+
+	@Override
+	public DenseVector prefix(double d) {
+		double[] newVec = new double[this.size() + 1];
+		newVec[0] = d;
+		for (int i = 0; i < this.size(); i++) {
+			newVec[i + 1] = this.get(i);
+		}
+		return new DenseVector(newVec);
+	}
+
+	@Override
+	public DenseVector append(double d) {
+		double[] newVec = new double[this.size() + 1];
+		for (int i = 0; i < this.size(); i++) {
+			newVec[i] = this.get(i);
+		}
+		newVec[this.size()] = d;
+		return new DenseVector(newVec);
+	}
+
+	@Override
+	public void scaleEqual(double d) {
+		for (int i = 0; i < this.size(); i++) {
+			this.data[i] *= d;
+		}
+	}
+
+	public DenseVector plus(DenseVector other) {
+		DenseVector r = this.clone();
+		DenseVector.apply(this, other, r, ((a, b) -> a + b));
+		return r;
+	}
+
+	@Override
+	public Vector plus(Vector other) {
+		if (other instanceof DenseVector) {
+			return plus((DenseVector) other);
+		} else {
+			return ((SparseVector) other).plus(this);
+		}
+	}
+
+	public DenseVector minus(DenseVector other) {
+		DenseVector r = this.clone();
+		DenseVector.apply(this, other, r, ((a, b) -> a - b));
+		return r;
+	}
+
+	@Override
+	public Vector minus(Vector other) {
+		if (other instanceof DenseVector) {
+			return minus((DenseVector) other);
+		} else {
+			return ((SparseVector) other).scale(-1.0).plus(this);
+		}
+	}
+
+	@Override
+	public DenseVector scale(double d) {
+		DenseVector r = new DenseVector(this.data);
+		for (int i = 0; i < this.size(); i++) {
+			r.data[i] *= d;
+		}
+		return r;
+	}
+
+	public void setEqual(DenseVector other) {
 
 Review comment:
   Can we add a simple java doc to these non-overriding public methods?

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