/*
* RandomRBFGenerator.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.MiscUtils;
import tr.gov.ulakbim.jDenetX.core.ObjectRepository;
import tr.gov.ulakbim.jDenetX.options.AbstractOptionHandler;
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.Random;
public class RandomRBFGenerator extends AbstractOptionHandler implements
InstanceStream {
@Override
public String getPurposeString() {
return "Generates a random radial basis function stream.";
}
private static final long serialVersionUID = 1L;
public IntOption modelRandomSeedOption = new IntOption("modelRandomSeed",
'r', "Seed for random generation of model.", 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.", 2, 2, Integer.MAX_VALUE);
public IntOption numAttsOption = new IntOption("numAtts", 'a',
"The number of attributes to generate.", 10, 0, Integer.MAX_VALUE);
public IntOption numCentroidsOption = new IntOption("numCentroids", 'n',
"The number of centroids in the model.", 50, 1, Integer.MAX_VALUE);
protected static class Centroid implements Serializable {
private static final long serialVersionUID = 1L;
public double[] centre;
public int classLabel;
public double stdDev;
}
protected InstancesHeader streamHeader;
protected Centroid[] centroids;
protected double[] centroidWeights;
protected Random instanceRandom;
@Override
public void prepareForUseImpl(TaskMonitor monitor,
ObjectRepository repository) {
monitor.setCurrentActivity("Preparing random RBF...", -1.0);
generateHeader();
generateCentroids();
restart();
}
public InstancesHeader getHeader() {
return this.streamHeader;
}
public long estimatedRemainingInstances() {
return -1;
}
public boolean hasMoreInstances() {
return true;
}
public boolean isRestartable() {
return true;
}
public void restart() {
this.instanceRandom = new Random(this.instanceRandomSeedOption
.getValue());
}
public Instance nextInstance() {
Centroid centroid = this.centroids[MiscUtils
.chooseRandomIndexBasedOnWeights(this.centroidWeights,
this.instanceRandom)];
int numAtts = this.numAttsOption.getValue();
double[] attVals = new double[numAtts + 1];
for (int i = 0; i < numAtts; i++) {
attVals[i] = (this.instanceRandom.nextDouble() * 2.0) - 1.0;
}
double magnitude = 0.0;
for (int i = 0; i < numAtts; i++) {
magnitude += attVals[i] * attVals[i];
}
magnitude = Math.sqrt(magnitude);
double desiredMag = this.instanceRandom.nextGaussian()
* centroid.stdDev;
double scale = desiredMag / magnitude;
for (int i = 0; i < numAtts; i++) {
attVals[i] = centroid.centre[i] + attVals[i] * scale;
}
Instance inst = new DenseInstance(1.0, attVals);
inst.setDataset(getHeader());
inst.setClassValue(centroid.classLabel);
return inst;
}
protected void generateHeader() {
FastVector attributes = new FastVector();
for (int i = 0; i < this.numAttsOption.getValue(); i++) {
attributes.addElement(new Attribute("att" + (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 generateCentroids() {
Random modelRand = new Random(this.modelRandomSeedOption.getValue());
this.centroids = new Centroid[this.numCentroidsOption.getValue()];
this.centroidWeights = new double[this.centroids.length];
for (int i = 0; i < this.centroids.length; i++) {
this.centroids[i] = new Centroid();
double[] randCentre = new double[this.numAttsOption.getValue()];
for (int j = 0; j < randCentre.length; j++) {
randCentre[j] = modelRand.nextDouble();
}
this.centroids[i].centre = randCentre;
this.centroids[i].classLabel = modelRand
.nextInt(this.numClassesOption.getValue());
this.centroids[i].stdDev = modelRand.nextDouble();
this.centroidWeights[i] = modelRand.nextDouble();
}
}
public void getDescription(StringBuilder sb, int indent) {
// TODO Auto-generated method stub
}
}