Java tutorial
/* * RandomTreeGenerator.java * Copyright (C) 2007 University of Waikato, Hamilton, New Zealand * @author Richard Kirkby (rkirkby@cs.waikato.ac.nz) * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ package tr.gov.ulakbim.jDenetX.streams.generators; import tr.gov.ulakbim.jDenetX.core.InstancesHeader; import tr.gov.ulakbim.jDenetX.core.ObjectRepository; import tr.gov.ulakbim.jDenetX.options.AbstractOptionHandler; import tr.gov.ulakbim.jDenetX.options.FloatOption; import tr.gov.ulakbim.jDenetX.options.IntOption; import tr.gov.ulakbim.jDenetX.streams.InstanceStream; import tr.gov.ulakbim.jDenetX.tasks.TaskMonitor; import weka.core.*; import java.io.Serializable; import java.util.ArrayList; import java.util.Random; public class RandomTreeGenerator extends AbstractOptionHandler implements InstanceStream { @Override public String getPurposeString() { return "Generates a stream based on a randomly generated tree."; } private static final long serialVersionUID = 1L; public IntOption treeRandomSeedOption = new IntOption("treeRandomSeed", 'r', "Seed for random generation of tree.", 1); public IntOption instanceRandomSeedOption = new IntOption("instanceRandomSeed", 'i', "Seed for random generation of instances.", 1); public IntOption numClassesOption = new IntOption("numClasses", 'c', "The number of classes to generate.", 8, 2, Integer.MAX_VALUE); public IntOption numNominalsOption = new IntOption("numNominals", 'o', "The number of nominal attributes to generate.", 0, 0, Integer.MAX_VALUE); public IntOption numNumericsOption = new IntOption("numNumerics", 'u', "The number of numeric attributes to generate.", 6, 0, Integer.MAX_VALUE); public IntOption numValsPerNominalOption = new IntOption("numValsPerNominal", 'v', "The number of values to generate per nominal attribute.", 5, 2, Integer.MAX_VALUE); public IntOption maxTreeDepthOption = new IntOption("maxTreeDepth", 'd', "The maximum depth of the tree concept.", 5, 0, Integer.MAX_VALUE); public IntOption firstLeafLevelOption = new IntOption("firstLeafLevel", 'l', "The first level of the tree above maxTreeDepth that can have leaves.", 3, 0, Integer.MAX_VALUE); public FloatOption leafFractionOption = new FloatOption("leafFraction", 'f', "The fraction of leaves per level from firstLeafLevel onwards.", 0.15, 0.0, 1.0); protected static class Node implements Serializable { private static final long serialVersionUID = 1L; public int classLabel; public int splitAttIndex; public double splitAttValue; public Node[] children; } protected Node treeRoot; protected InstancesHeader streamHeader; protected Random instanceRandom; @Override public void prepareForUseImpl(TaskMonitor monitor, ObjectRepository repository) { monitor.setCurrentActivity("Preparing random tree...", -1.0); generateHeader(); generateRandomTree(); restart(); } public long estimatedRemainingInstances() { return -1; } public boolean isRestartable() { return true; } public void restart() { this.instanceRandom = new Random(this.instanceRandomSeedOption.getValue()); } public InstancesHeader getHeader() { return this.streamHeader; } public boolean hasMoreInstances() { return true; } public Instance nextInstance() { double[] attVals = new double[this.numNominalsOption.getValue() + this.numNumericsOption.getValue()]; InstancesHeader header = getHeader(); Instance inst = new DenseInstance(header.numAttributes()); for (int i = 0; i < attVals.length; i++) { attVals[i] = i < this.numNominalsOption.getValue() ? this.instanceRandom.nextInt(this.numValsPerNominalOption.getValue()) : this.instanceRandom.nextDouble(); inst.setValue(i, attVals[i]); } inst.setDataset(header); inst.setClassValue(classifyInstance(this.treeRoot, attVals)); return inst; } protected int classifyInstance(Node node, double[] attVals) { if (node.children == null) { return node.classLabel; } if (node.splitAttIndex < this.numNominalsOption.getValue()) { return classifyInstance(node.children[(int) attVals[node.splitAttIndex]], attVals); } return classifyInstance(node.children[attVals[node.splitAttIndex] < node.splitAttValue ? 0 : 1], attVals); } protected void generateHeader() { FastVector attributes = new FastVector(); FastVector nominalAttVals = new FastVector(); for (int i = 0; i < this.numValsPerNominalOption.getValue(); i++) { nominalAttVals.addElement("value" + (i + 1)); } for (int i = 0; i < this.numNominalsOption.getValue(); i++) { attributes.addElement(new Attribute("nominal" + (i + 1), nominalAttVals)); } for (int i = 0; i < this.numNumericsOption.getValue(); i++) { attributes.addElement(new Attribute("numeric" + (i + 1))); } FastVector classLabels = new FastVector(); for (int i = 0; i < this.numClassesOption.getValue(); i++) { classLabels.addElement("class" + (i + 1)); } attributes.addElement(new Attribute("class", classLabels)); this.streamHeader = new InstancesHeader( new Instances(getCLICreationString(InstanceStream.class), attributes, 0)); this.streamHeader.setClassIndex(this.streamHeader.numAttributes() - 1); } protected void generateRandomTree() { Random treeRand = new Random(this.treeRandomSeedOption.getValue()); ArrayList<Integer> nominalAttCandidates = new ArrayList<Integer>(this.numNominalsOption.getValue()); for (int i = 0; i < this.numNominalsOption.getValue(); i++) { nominalAttCandidates.add(i); } double[] minNumericVals = new double[this.numNumericsOption.getValue()]; double[] maxNumericVals = new double[this.numNumericsOption.getValue()]; for (int i = 0; i < this.numNumericsOption.getValue(); i++) { minNumericVals[i] = 0.0; maxNumericVals[i] = 1.0; } this.treeRoot = generateRandomTreeNode(0, nominalAttCandidates, minNumericVals, maxNumericVals, treeRand); } protected Node generateRandomTreeNode(int currentDepth, ArrayList<Integer> nominalAttCandidates, double[] minNumericVals, double[] maxNumericVals, Random treeRand) { if ((currentDepth >= this.maxTreeDepthOption.getValue()) || ((currentDepth >= this.firstLeafLevelOption.getValue()) && (this.leafFractionOption.getValue() >= (1.0 - treeRand.nextDouble())))) { Node leaf = new Node(); leaf.classLabel = treeRand.nextInt(this.numClassesOption.getValue()); return leaf; } Node node = new Node(); int chosenAtt = treeRand.nextInt(nominalAttCandidates.size() + this.numNumericsOption.getValue()); if (chosenAtt < nominalAttCandidates.size()) { node.splitAttIndex = nominalAttCandidates.get(chosenAtt); node.children = new Node[this.numValsPerNominalOption.getValue()]; ArrayList<Integer> newNominalCandidates = new ArrayList<Integer>(nominalAttCandidates); newNominalCandidates.remove(Integer.valueOf(node.splitAttIndex)); newNominalCandidates.trimToSize(); for (int i = 0; i < node.children.length; i++) { node.children[i] = generateRandomTreeNode(currentDepth + 1, newNominalCandidates, minNumericVals, maxNumericVals, treeRand); } } else { int numericIndex = chosenAtt - nominalAttCandidates.size(); node.splitAttIndex = this.numNominalsOption.getValue() + numericIndex; double minVal = minNumericVals[numericIndex]; double maxVal = maxNumericVals[numericIndex]; node.splitAttValue = ((maxVal - minVal) * treeRand.nextDouble()) + minVal; node.children = new Node[2]; double[] newMaxVals = maxNumericVals.clone(); newMaxVals[numericIndex] = node.splitAttValue; node.children[0] = generateRandomTreeNode(currentDepth + 1, nominalAttCandidates, minNumericVals, newMaxVals, treeRand); double[] newMinVals = minNumericVals.clone(); newMinVals[numericIndex] = node.splitAttValue; node.children[1] = generateRandomTreeNode(currentDepth + 1, nominalAttCandidates, newMinVals, maxNumericVals, treeRand); } return node; } public void getDescription(StringBuilder sb, int indent) { // TODO Auto-generated method stub } }