userguide: add samples for various RandomVectorGenerator implementations (e.g. low discrepancy vs. uniform).
git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1485347 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Thomas Neidhart
parent
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/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.apache.commons.math3.userguide;
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import java.awt.Color;
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import java.awt.Dimension;
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import java.awt.Graphics;
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import java.awt.Graphics2D;
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import java.awt.GridBagConstraints;
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import java.awt.GridBagLayout;
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import java.awt.Insets;
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import java.awt.RenderingHints;
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import java.awt.geom.Rectangle2D;
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import java.util.ArrayList;
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import java.util.List;
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import javax.swing.JComponent;
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import javax.swing.JFrame;
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import javax.swing.JLabel;
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import javax.swing.JTextArea;
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import javax.swing.SwingUtilities;
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import org.apache.commons.math3.geometry.euclidean.twod.Vector2D;
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import org.apache.commons.math3.random.HaltonSequenceGenerator;
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import org.apache.commons.math3.random.JDKRandomGenerator;
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import org.apache.commons.math3.random.MersenneTwister;
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import org.apache.commons.math3.random.RandomGenerator;
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import org.apache.commons.math3.random.RandomVectorGenerator;
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import org.apache.commons.math3.random.SobolSequenceGenerator;
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import org.apache.commons.math3.random.UncorrelatedRandomVectorGenerator;
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import org.apache.commons.math3.random.UniformRandomGenerator;
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import org.apache.commons.math3.util.FastMath;
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import org.apache.commons.math3.util.Pair;
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/**
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* Plots 2D samples drawn from various pseudo / quasi-random generators.
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*/
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public class RandomVectorGeneratorExamples {
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public static List<Vector2D> makeCircle(int samples, final RandomVectorGenerator generator) {
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List<Vector2D> points = new ArrayList<Vector2D>();
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for (double i = 0; i < samples; i++) {
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double[] vector = generator.nextVector();
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Vector2D point = new Vector2D(vector);
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points.add(point);
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}
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// normalize points first
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points = normalize(points);
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// now test if the sample is within the unit circle
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List<Vector2D> circlePoints = new ArrayList<Vector2D>();
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for (Vector2D p : points) {
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double criteria = FastMath.pow(p.getX(), 2) + FastMath.pow(p.getY(), 2);
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if (criteria < 1.0) {
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circlePoints.add(p);
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}
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}
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return circlePoints;
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}
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public static List<Vector2D> makeRandom(int samples, RandomVectorGenerator generator) {
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List<Vector2D> points = new ArrayList<Vector2D>();
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for (double i = 0; i < samples; i++) {
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double[] vector = generator.nextVector();
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Vector2D point = new Vector2D(vector);
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points.add(point);
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}
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return normalize(points);
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}
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public static List<Vector2D> normalize(final List<Vector2D> input) {
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// find the mininum and maximum x value in the dataset
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double minX = Double.MAX_VALUE;
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double maxX = Double.MIN_VALUE;
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for (Vector2D p : input) {
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minX = FastMath.min(minX, p.getX());
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maxX = FastMath.max(maxX, p.getX());
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}
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double minY, maxY;
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// use the minimum to detect if we either have input values in the range [0, 1] or [-sqrt(3), sqrt(3)]
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if (FastMath.abs(minX) < 0.1) {
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minX = minY = 0.0;
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maxX = maxY = 1.0;
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} else {
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minX = minY = -FastMath.sqrt(3);
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maxX = maxY = FastMath.sqrt(3);
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}
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double rangeX = maxX - minX;
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double rangeY = maxY - minY;
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List<Vector2D> points = new ArrayList<Vector2D>();
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for (Vector2D p : input) {
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double[] arr = p.toArray();
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// normalize to the range [-1, 1]
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arr[0] = (arr[0] - minX) / rangeX * 2 - 1;
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arr[1] = (arr[1] - minY) / rangeY * 2 - 1;
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points.add(new Vector2D(arr));
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}
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return points;
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}
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public static class Display extends JFrame {
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private static final long serialVersionUID = -8846964550416589808L;
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public Display() {
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setTitle("Pseudo/Quasi-random examples");
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setSize(800, 800);
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setLocationRelativeTo(null);
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setDefaultCloseOperation(EXIT_ON_CLOSE);
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setLayout(new GridBagLayout());
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int[] datasets = new int[] { 256, 1000, 2500, 1000 };
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List<Pair<String, RandomVectorGenerator>> generators = new ArrayList<Pair<String, RandomVectorGenerator>>();
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generators.add(new Pair<String, RandomVectorGenerator>("Uncorrelated\nUniform(JDK)",
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new UncorrelatedRandomVectorGenerator(2, new UniformRandomGenerator(new JDKRandomGenerator()))));
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generators.add(new Pair<String, RandomVectorGenerator>("Independent\nRandom(MT)", new RandomVectorGenerator() {
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RandomGenerator[] rngs = new RandomGenerator[] {
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new MersenneTwister(0),
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new MersenneTwister(1)
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};
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public double[] nextVector() {
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final double[] vector = new double[2];
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vector[0] = rngs[0].nextDouble();
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vector[1] = rngs[1].nextDouble();
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return vector;
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}
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}));
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generators.add(new Pair<String, RandomVectorGenerator>("HaltonSequence", new HaltonSequenceGenerator(2)));
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generators.add(new Pair<String, RandomVectorGenerator>("SobolSequence", new SobolSequenceGenerator(2)));
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GridBagConstraints c = new GridBagConstraints();
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c.fill = GridBagConstraints.VERTICAL;
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c.gridx = 1;
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c.gridy = 0;
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c.insets = new Insets(2, 2, 2, 2);
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for (Pair<String, RandomVectorGenerator> pair : generators) {
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JTextArea text = new JTextArea(pair.getFirst());
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text.setEditable(false);
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text.setOpaque(false);
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add(text, c);
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c.gridx++;
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}
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int saveY = ++c.gridy;
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c.gridx = 0;
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for (int type = 0; type < 4; type++) {
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JLabel text = new JLabel("n=" + String.valueOf(datasets[type]));
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text.setOpaque(false);
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add(text, c);
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c.gridy++;
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}
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c.gridy = saveY;
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for (int type = 0; type < 4; type++) {
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c.gridx = 1;
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for (Pair<String, RandomVectorGenerator> pair : generators) {
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List<Vector2D> points = null;
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int samples = datasets[type];
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switch (type) {
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case 0:
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points = makeRandom(samples, pair.getValue());
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break;
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case 1:
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points = makeRandom(samples, pair.getValue());
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break;
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case 2:
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points = makeRandom(samples, pair.getValue());
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break;
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case 3:
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points = makeCircle(samples, pair.getValue());
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break;
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}
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add(new Plot(points), c);
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c.gridx++;
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}
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c.gridy++;
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}
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}
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}
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public static class Plot extends JComponent {
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private static final long serialVersionUID = 4546352048750419587L;
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private static double PAD = 10;
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private List<Vector2D> points;
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public Plot(final List<Vector2D> points) {
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this.points = points;
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}
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protected void paintComponent(Graphics g) {
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super.paintComponent(g);
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Graphics2D g2 = (Graphics2D)g;
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g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
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RenderingHints.VALUE_ANTIALIAS_ON);
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int w = getWidth();
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int h = getHeight();
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g2.clearRect(0, 0, w, h);
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g2.setPaint(Color.black);
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g2.drawRect(0, 0, w - 1, h - 1);
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for (Vector2D point : points) {
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Vector2D p = transform(point, w, h);
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double[] arr = p.toArray();
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g2.draw(new Rectangle2D.Double(arr[0] - 1, arr[1] - 1, 2, 2));
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}
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}
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@Override
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public Dimension getPreferredSize() {
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return new Dimension(140, 140);
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}
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private Vector2D transform(Vector2D point, int width, int height) {
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double[] arr = point.toArray();
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return new Vector2D(new double[] { PAD + (arr[0] + 1) / 2.0 * (width - 2 * PAD),
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height - PAD - (arr[1] + 1) / 2.0 * (height - 2 * PAD) });
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}
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}
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public static void main(String[] args) {
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SwingUtilities.invokeLater(new Runnable() {
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public void run() {
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Display d = new Display();
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d.setVisible(true);
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}
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});
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}
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}
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