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Posted to commits@commons.apache.org by er...@apache.org on 2015/09/18 00:15:50 UTC
[math] MATH-1270
Repository: commons-math
Updated Branches:
refs/heads/master fb7e1e265 -> 924e1e906
MATH-1270
Visualization of quantization error.
Project: http://git-wip-us.apache.org/repos/asf/commons-math/repo
Commit: http://git-wip-us.apache.org/repos/asf/commons-math/commit/924e1e90
Tree: http://git-wip-us.apache.org/repos/asf/commons-math/tree/924e1e90
Diff: http://git-wip-us.apache.org/repos/asf/commons-math/diff/924e1e90
Branch: refs/heads/master
Commit: 924e1e9064f90d958b4f57e9c9c0c543bd19dcfb
Parents: fb7e1e2
Author: Gilles <er...@apache.org>
Authored: Fri Sep 18 00:14:39 2015 +0200
Committer: Gilles <er...@apache.org>
Committed: Fri Sep 18 00:14:39 2015 +0200
----------------------------------------------------------------------
src/changes/changes.xml | 2 +-
.../neuralnet/twod/util/QuantizationError.java | 76 ++++++++++++++++++++
2 files changed, 77 insertions(+), 1 deletion(-)
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http://git-wip-us.apache.org/repos/asf/commons-math/blob/924e1e90/src/changes/changes.xml
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diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index 7f04ede..27a5ae1 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -60,7 +60,7 @@ If the output is not quite correct, check for invisible trailing spaces!
<action dev="erans" type="add" issue="MATH-1270"> <!-- backported to 3.6 -->
Various SOFM visualizations (in package "o.a.c.m.ml.neuralnet.twod.util"):
Unified distance matrix, hit histogram, smoothed data histograms,
- topographic error.
+ topographic error, quantization error.
</action>
<action dev="erans" type="add" issue="MATH-1268"> <!-- backported to 3.6 -->
New interfaces to be implemented by algorithms that visualizes properties
http://git-wip-us.apache.org/repos/asf/commons-math/blob/924e1e90/src/main/java/org/apache/commons/math4/ml/neuralnet/twod/util/QuantizationError.java
----------------------------------------------------------------------
diff --git a/src/main/java/org/apache/commons/math4/ml/neuralnet/twod/util/QuantizationError.java b/src/main/java/org/apache/commons/math4/ml/neuralnet/twod/util/QuantizationError.java
new file mode 100644
index 0000000..e7bb19e
--- /dev/null
+++ b/src/main/java/org/apache/commons/math4/ml/neuralnet/twod/util/QuantizationError.java
@@ -0,0 +1,76 @@
+/*
+ * 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.commons.math4.ml.neuralnet.twod.util;
+
+import org.apache.commons.math4.ml.neuralnet.MapUtils;
+import org.apache.commons.math4.ml.neuralnet.Neuron;
+import org.apache.commons.math4.ml.neuralnet.twod.NeuronSquareMesh2D;
+import org.apache.commons.math4.ml.distance.DistanceMeasure;
+
+/**
+ * Computes the quantization error histogram.
+ * Each bin will contain the average of the distances between samples
+ * mapped to the corresponding unit and the weight vector of that unit.
+ */
+public class QuantizationError implements MapDataVisualization {
+ /** Distance. */
+ private final DistanceMeasure distance;
+
+ /**
+ * @param distance Distance.
+ */
+ public QuantizationError(DistanceMeasure distance) {
+ this.distance = distance;
+ }
+
+ /** {@inheritDoc} */
+ @Override
+ public double[][] computeImage(NeuronSquareMesh2D map,
+ Iterable<double[]> data) {
+ final int nR = map.getNumberOfRows();
+ final int nC = map.getNumberOfColumns();
+
+ final LocationFinder finder = new LocationFinder(map);
+
+ // Hit bins.
+ final int[][] hit = new int[nR][nC];
+ // Error bins.
+ final double[][] error = new double[nR][nC];
+
+ for (double[] sample : data) {
+ final Neuron best = MapUtils.findBest(sample, map, distance);
+
+ final LocationFinder.Location loc = finder.getLocation(best);
+ final int row = loc.getRow();
+ final int col = loc.getColumn();
+ hit[row][col] += 1;
+ error[row][col] += distance.compute(sample, best.getFeatures());
+ }
+
+ for (int r = 0; r < nR; r++) {
+ for (int c = 0; c < nC; c++) {
+ final int count = hit[r][c];
+ if (count != 0) {
+ error[r][c] /= count;
+ }
+ }
+ }
+
+ return error;
+ }
+}