Java tutorial
/* * 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. */ import java.awt.BasicStroke; import java.awt.Color; import java.awt.Frame; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Toolkit; import java.awt.event.WindowAdapter; import java.awt.event.WindowEvent; import java.awt.geom.AffineTransform; import java.awt.geom.Ellipse2D; import java.awt.geom.Rectangle2D; import java.io.IOException; import java.util.Collection; import java.util.HashMap; import java.util.List; import java.util.Map; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FileStatus; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.io.IntWritable; import org.apache.hadoop.io.SequenceFile; import org.apache.hadoop.io.Text; import org.apache.mahout.clustering.AbstractCluster; import org.apache.mahout.clustering.Cluster; import org.apache.mahout.clustering.classify.WeightedVectorWritable; import org.apache.mahout.clustering.UncommonDistributions; import org.apache.mahout.clustering.iterator.ClusterWritable; import org.apache.mahout.common.Pair; import org.apache.mahout.common.RandomUtils; import org.apache.mahout.common.iterator.sequencefile.PathFilters; import org.apache.mahout.common.iterator.sequencefile.PathType; import org.apache.mahout.common.iterator.sequencefile.SequenceFileDirValueIterable; import org.apache.mahout.common.iterator.sequencefile.SequenceFileIterable; import org.apache.mahout.math.DenseVector; import org.apache.mahout.math.Vector; import org.apache.mahout.math.VectorWritable; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.google.common.collect.Lists; import com.google.common.io.Closeables; public class DisplayClustering extends Frame { private static final Logger log = LoggerFactory.getLogger(DisplayClustering.class); protected static final int DS = 72; // default scale = 72 pixels per inch protected static final int SIZE = 8; // screen size in inches private static final Collection<Vector> SAMPLE_PARAMS = Lists.newArrayList(); protected static final List<VectorWritable> SAMPLE_DATA = Lists.newArrayList(); protected static final List<List<Cluster>> CLUSTERS = Lists.newArrayList(); static final Color[] COLORS = { Color.red, Color.orange, Color.yellow, Color.green, Color.blue, Color.magenta, Color.lightGray }; protected static final double T1 = 3.0; protected static final double T2 = 2.8; static double significance = 0.05; protected static int res; // screen resolution public DisplayClustering() { initialize(); this.setTitle("Sample Data"); } public void initialize() { // Get screen resolution res = Toolkit.getDefaultToolkit().getScreenResolution(); // Set Frame size in inches this.setSize(SIZE * res, SIZE * res); this.setVisible(true); this.setTitle("Asymmetric Sample Data"); // Window listener to terminate program. this.addWindowListener(new WindowAdapter() { @Override public void windowClosing(WindowEvent e) { System.exit(0); } }); } public static void main(String[] args) throws Exception { RandomUtils.useTestSeed(); generateSamples(); new DisplayClustering(); } // Override the paint() method @Override public void paint(Graphics g) { Graphics2D g2 = (Graphics2D) g; plotSampleData(g2); plotSampleParameters(g2); plotClusters(g2); } protected static void plotClusters(Graphics2D g2) { int cx = CLUSTERS.size() - 1; for (List<Cluster> clusters : CLUSTERS) { g2.setStroke(new BasicStroke(cx == 0 ? 3 : 1)); g2.setColor(COLORS[Math.min(COLORS.length - 1, cx--)]); for (Cluster cluster : clusters) { plotEllipse(g2, cluster.getCenter(), cluster.getRadius().times(3)); } } } protected static void plotSampleParameters(Graphics2D g2) { Vector v = new DenseVector(2); Vector dv = new DenseVector(2); g2.setColor(Color.RED); for (Vector param : SAMPLE_PARAMS) { v.set(0, param.get(0)); v.set(1, param.get(1)); dv.set(0, param.get(2) * 3); dv.set(1, param.get(3) * 3); plotEllipse(g2, v, dv); } } protected static void plotSampleData(Graphics2D g2) { double sx = (double) res / DS; g2.setTransform(AffineTransform.getScaleInstance(sx, sx)); // plot the axes g2.setColor(Color.BLACK); Vector dv = new DenseVector(2).assign(SIZE / 2.0); plotRectangle(g2, new DenseVector(2).assign(2), dv); plotRectangle(g2, new DenseVector(2).assign(-2), dv); // plot the sample data g2.setColor(Color.DARK_GRAY); dv.assign(0.03); for (VectorWritable v : SAMPLE_DATA) { plotRectangle(g2, v.get(), dv); } } /** * This method plots points and colors them according to their cluster * membership, rather than drawing ellipses. * * As of commit, this method is used only by K-means spectral clustering. * Since the cluster assignments are set within the eigenspace of the data, it * is not inherent that the original data cluster as they would in K-means: * that is, as symmetric gaussian mixtures. * * Since Spectral K-Means uses K-Means to cluster the eigenspace data, the raw * output is not directly usable. Rather, the cluster assignments from the raw * output need to be transferred back to the original data. As such, this * method will read the SequenceFile cluster results of K-means and transfer * the cluster assignments to the original data, coloring them appropriately. * * @param g2 * @param data */ protected static void plotClusteredSampleData(Graphics2D g2, Path data) { double sx = (double) res / DS; g2.setTransform(AffineTransform.getScaleInstance(sx, sx)); g2.setColor(Color.BLACK); Vector dv = new DenseVector(2).assign(SIZE / 2.0); plotRectangle(g2, new DenseVector(2).assign(2), dv); plotRectangle(g2, new DenseVector(2).assign(-2), dv); // plot the sample data, colored according to the cluster they belong to dv.assign(0.03); Path clusteredPointsPath = new Path(data, "clusteredPoints"); Path inputPath = new Path(clusteredPointsPath, "part-m-00000"); Map<Integer, Color> colors = new HashMap<Integer, Color>(); int point = 0; for (Pair<IntWritable, WeightedVectorWritable> record : new SequenceFileIterable<IntWritable, WeightedVectorWritable>( inputPath, new Configuration())) { int clusterId = record.getFirst().get(); VectorWritable v = SAMPLE_DATA.get(point++); Integer key = clusterId; if (!colors.containsKey(key)) { colors.put(key, COLORS[Math.min(COLORS.length - 1, colors.size())]); } plotClusteredRectangle(g2, v.get(), dv, colors.get(key)); } } /** * Identical to plotRectangle(), but with the option of setting the color of * the rectangle's stroke. * * NOTE: This should probably be refactored with plotRectangle() since most of * the code here is direct copy/paste from that method. * * @param g2 * A Graphics2D context. * @param v * A vector for the rectangle's center. * @param dv * A vector for the rectangle's dimensions. * @param color * The color of the rectangle's stroke. */ protected static void plotClusteredRectangle(Graphics2D g2, Vector v, Vector dv, Color color) { double[] flip = { 1, -1 }; Vector v2 = v.times(new DenseVector(flip)); v2 = v2.minus(dv.divide(2)); int h = SIZE / 2; double x = v2.get(0) + h; double y = v2.get(1) + h; g2.setStroke(new BasicStroke(1)); g2.setColor(color); g2.draw(new Rectangle2D.Double(x * DS, y * DS, dv.get(0) * DS, dv.get(1) * DS)); } /** * Draw a rectangle on the graphics context * * @param g2 * a Graphics2D context * @param v * a Vector of rectangle center * @param dv * a Vector of rectangle dimensions */ protected static void plotRectangle(Graphics2D g2, Vector v, Vector dv) { double[] flip = { 1, -1 }; Vector v2 = v.times(new DenseVector(flip)); v2 = v2.minus(dv.divide(2)); int h = SIZE / 2; double x = v2.get(0) + h; double y = v2.get(1) + h; g2.draw(new Rectangle2D.Double(x * DS, y * DS, dv.get(0) * DS, dv.get(1) * DS)); } /** * Draw an ellipse on the graphics context * * @param g2 * a Graphics2D context * @param v * a Vector of ellipse center * @param dv * a Vector of ellipse dimensions */ protected static void plotEllipse(Graphics2D g2, Vector v, Vector dv) { double[] flip = { 1, -1 }; Vector v2 = v.times(new DenseVector(flip)); v2 = v2.minus(dv.divide(2)); int h = SIZE / 2; double x = v2.get(0) + h; double y = v2.get(1) + h; g2.draw(new Ellipse2D.Double(x * DS, y * DS, dv.get(0) * DS, dv.get(1) * DS)); } protected static void generateSamples() { generateSamples(500, 1, 1, 3); generateSamples(300, 1, 0, 0.5); generateSamples(300, 0, 2, 0.1); } protected static void generate2dSamples() { generate2dSamples(500, 1, 1, 3, 1); generate2dSamples(300, 1, 0, 0.5, 1); generate2dSamples(300, 0, 2, 0.1, 0.5); } /** * Generate random samples and add them to the sampleData * * @param num * int number of samples to generate * @param mx * double x-value of the sample mean * @param my * double y-value of the sample mean * @param sd * double standard deviation of the samples */ protected static void generateSamples(int num, double mx, double my, double sd) { double[] params = { mx, my, sd, sd }; SAMPLE_PARAMS.add(new DenseVector(params)); log.info("Generating {} samples m=[{}, {}] sd={}", num, mx, my, sd); for (int i = 0; i < num; i++) { SAMPLE_DATA.add(new VectorWritable(new DenseVector( new double[] { UncommonDistributions.rNorm(mx, sd), UncommonDistributions.rNorm(my, sd) }))); } } protected static void writeSampleData(Path output) throws IOException { Configuration conf = new Configuration(); FileSystem fs = FileSystem.get(output.toUri(), conf); SequenceFile.Writer writer = new SequenceFile.Writer(fs, conf, output, Text.class, VectorWritable.class); try { int i = 0; for (VectorWritable vw : SAMPLE_DATA) { writer.append(new Text("sample_" + i++), vw); } } finally { Closeables.close(writer, false); } } protected static List<Cluster> readClustersWritable(Path clustersIn) { List<Cluster> clusters = Lists.newArrayList(); Configuration conf = new Configuration(); for (ClusterWritable value : new SequenceFileDirValueIterable<ClusterWritable>(clustersIn, PathType.LIST, PathFilters.logsCRCFilter(), conf)) { Cluster cluster = value.getValue(); log.info("Reading Cluster:{} center:{} numPoints:{} radius:{}", cluster.getId(), AbstractCluster.formatVector(cluster.getCenter(), null), cluster.getNumObservations(), AbstractCluster.formatVector(cluster.getRadius(), null)); clusters.add(cluster); } return clusters; } protected static void loadClustersWritable(Path output) throws IOException { Configuration conf = new Configuration(); FileSystem fs = FileSystem.get(output.toUri(), conf); for (FileStatus s : fs.listStatus(output, new ClustersFilter())) { List<Cluster> clusters = readClustersWritable(s.getPath()); CLUSTERS.add(clusters); } } /** * Generate random samples and add them to the sampleData * * @param num * int number of samples to generate * @param mx * double x-value of the sample mean * @param my * double y-value of the sample mean * @param sdx * double x-value standard deviation of the samples * @param sdy * double y-value standard deviation of the samples */ protected static void generate2dSamples(int num, double mx, double my, double sdx, double sdy) { double[] params = { mx, my, sdx, sdy }; SAMPLE_PARAMS.add(new DenseVector(params)); log.info("Generating {} samples m=[{}, {}] sd=[{}, {}]", num, mx, my, sdx, sdy); for (int i = 0; i < num; i++) { SAMPLE_DATA.add(new VectorWritable(new DenseVector( new double[] { UncommonDistributions.rNorm(mx, sdx), UncommonDistributions.rNorm(my, sdy) }))); } } protected static boolean isSignificant(Cluster cluster) { return (double) cluster.getNumObservations() / SAMPLE_DATA.size() > significance; } }