fouriergeneratingmutation.java

一个很好的LIBSVM的JAVA源码。对于要研究和改进SVM算法的学者。可以参考。来自数据挖掘工具YALE工具包。

/*
 *  YALE - Yet Another Learning Environment
 *  Copyright (C) 2001-2004
 *      Simon Fischer, Ralf Klinkenberg, Ingo Mierswa, 
 *          Katharina Morik, Oliver Ritthoff
 *      Artificial Intelligence Unit
 *      Computer Science Department
 *      University of Dortmund
 *      44221 Dortmund,  Germany
 *  email: [e-mail]
 *  web:   http://yale.cs.uni-dortmund.de/
 *
 *  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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 *  USA.
 */
package edu.udo.cs.yale.operator.features.ga;

import edu.udo.cs.yale.generator.FeatureGenerator;
import edu.udo.cs.yale.generator.SinusFactory;
import edu.udo.cs.yale.generator.GenerationException;
import edu.udo.cs.yale.operator.OperatorException;
import edu.udo.cs.yale.operator.features.IndividualOperator;
import edu.udo.cs.yale.example.AttributeWeightedExampleSet;
import edu.udo.cs.yale.example.Attribute;
import edu.udo.cs.yale.example.Tools;
import edu.udo.cs.yale.tools.RandomGenerator;
import edu.udo.cs.yale.tools.LogService;

import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

/** The mutation operator for FourierGGA. This operator adds single attributes from the original set, 
 *  creates new ones and deselect single attributes. For each freshly added attribute a fourier generation will 
 *  will be performed.
 *
 *  @version $Id: FourierGeneratingMutation.java,v 2.5 2004/08/27 11:57:36 ingomierswa Exp $
 *  @see FourierGGA */
public class FourierGeneratingMutation extends IndividualOperator {

    private List generators;
    private List originalAttributes;
    private double p;
    private int numberOfConstructed;
    private int numberOfOriginal;
    private SinusFactory factory = null;
    private int maxDepth;
    private String[] unusableFunctions = new String[0];

    private RandomGenerator random = RandomGenerator.getGlobalRandomGenerator();

    public FourierGeneratingMutation(List originalAttributes, double p, List generators,
				     int numberOfConstructed, int numberOfOriginal,
				     int maxPeaks, int adaptionType, int attributesPerPeak, double epsilon,
				     int maxDepth, String[] unusableFunctions) {
	this.originalAttributes = originalAttributes;
	this.p = p;
	this.generators = generators;
	this.numberOfConstructed = numberOfConstructed;
	this.numberOfOriginal = numberOfOriginal;
	this.factory = new SinusFactory(maxPeaks);
	this.factory.setAdaptionType(adaptionType);
	this.factory.setEpsilon(epsilon);
	this.factory.setAttributePerPeak(attributesPerPeak);
	this.maxDepth = maxDepth;
	this.unusableFunctions = unusableFunctions;
    }

    /** Performs one of the following three mutations:
     *  <ul>
     *    <li>add a newly generated attribute</li>
     *    <li>add an original attribute</li>
     *    <li>remove an attribute</li>
     *  </ul> */
    public List operate(AttributeWeightedExampleSet exampleSet) throws Exception {
	LinkedList l = new LinkedList();
	AttributeWeightedExampleSet clone = (AttributeWeightedExampleSet)exampleSet.clone();

	try {
	    int numberOriginal = addOriginalAttribute(clone);
	    int numberCreated  = addGeneratedAttribute(clone);
	    deselect(clone, numberOriginal + numberCreated);
	} catch (GenerationException e) {
	    LogService.logMessage("GeneratingMutation: Exception occured during generation of attributes, using original example set instead.", LogService.WARNING);
	    l.add(exampleSet);
	}
	
	if (clone.getNumberOfUsedAttributes() > 0) {
	    Iterator i = exampleSet.getUserDataKeys().iterator();
	    while (i.hasNext()) {
		String key = (String)i.next();
		clone.setUserData(key, exampleSet.getUserData(key));
	    }
	    l.add(clone);
	} else {
	    l.add(exampleSet);
	}
	return l;
    }

    /** Adds a new attribute. Returns true, if generation was possible. */
    private int addGeneratedAttribute(AttributeWeightedExampleSet exampleSet) throws OperatorException {
	int counter = 0;
	for (int k = 0; k < numberOfConstructed; k++) {
	    if (random.nextDouble() < p) {
		FeatureGenerator generator = FeatureGenerator.selectGenerator(exampleSet, generators, maxDepth, unusableFunctions);
		if (generator != null) {
		    generator = generator.newInstance();
		    Attribute[] args = Tools.getRandomCompatibleAttributes(exampleSet, generator, maxDepth, unusableFunctions);
		    generator.setArguments(args);
		    List generatorList = new LinkedList();
		    generatorList.add(generator);
		    
		    List newAttributes = FeatureGenerator.generateAll(exampleSet.getExampleTable(), generatorList);
		    exampleSet.addAllAttributes(newAttributes);
		    counter += newAttributes.size();
		    
		    Iterator i = newAttributes.iterator();
		    List sinAttributes = new LinkedList();
		    Attribute label = exampleSet.getLabel();
		    while (i.hasNext()) {
			Attribute current = (Attribute)i.next();
			//System.out.println("### GENERATED: " + current.getConstructionDescription());
			if ((!current.isNominal()) && (current.getConstructionDescription().indexOf("sin") == -1)) { 
			    List peaks = factory.getAttributePeaks(exampleSet, label, current);
			    sinAttributes.addAll(peaks);
			}
		    }
		    
		    if (sinAttributes.size() > 0)
			factory.generateSinusFunctions(exampleSet, sinAttributes);
		    counter += sinAttributes.size();
		}
	    }
	}
	return counter;
    }

    private int addOriginalAttribute(AttributeWeightedExampleSet exampleSet) 
	throws GenerationException, OperatorException {
	int counter = 0;
	for (int k = 0; k < numberOfOriginal; k++) {
	    if (random.nextDouble() < p) {
		int i = random.nextInt(originalAttributes.size());
		Attribute originalAttribute = (Attribute)originalAttributes.get(i);
		if (exampleSet.getAttribute(originalAttribute.getName()) == null) {
		    //System.out.println("### ADD ORIGINAL: " + originalAttribute.getName());
		    exampleSet.addAttribute(originalAttribute);
		    counter++;
		}

		// add sinus functions of the original attribute 
		List peaks = factory.getAttributePeaks(exampleSet, exampleSet.getLabel(), originalAttribute);
		if (peaks.size() > 0)
		    factory.generateSinusFunctions(exampleSet, peaks);
		counter += peaks.size();
	    }
	}
	return counter;
    }

    private void deselect(AttributeWeightedExampleSet exampleSet, int m) {
	int n = exampleSet.getNumberOfAttributes();
	for (int i = n-1; i >= 0; i--) {
	    if (random.nextDouble() < m* ((double)p / (double)exampleSet.getNumberOfAttributes())) {
		exampleSet.removeAttribute(i);
	    }
	}
    }
}