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 <[email protected]> Authored: Fri Sep 18 00:14:39 2015 +0200 Committer: Gilles <[email protected]> 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(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/commons-math/blob/924e1e90/src/changes/changes.xml ---------------------------------------------------------------------- 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; + } +}
