attributegenerator.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;

import edu.udo.cs.yale.example.AttributeWeightedExampleSet;
import edu.udo.cs.yale.example.Tools;
import edu.udo.cs.yale.tools.RandomGenerator;
import edu.udo.cs.yale.generator.*;
import edu.udo.cs.yale.example.Attribute;

import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;

/** This PopulationOperator generates new attributes in an individual's example table. Given a generation
 *  probability <tt>pGenerate</p> and the maximal number of new attributes it generates on average
 *  <tt>pGenerate</tt> * <tt>numberOfNewAttributes</tt> new attributes using generators from the list
 *  <tt>generatorList</tt> <br/>
 *
 *  This operator can never handle value series but only single attributes.
 *
 *  @author ingo
 *  @version 29.05.2001 <br>
 */
public class AttributeGenerator extends IndividualOperator {

    /** Probability to generate a new attribute.
     */
    private double pGenerate;

    /** Maximal number of newly generated attributes.
     */
    private int numberOfNewAttributes;

    /** A list of applicable generators.
     */
    private List generatorList;

    /** Creates a new <tt>AttributeGenerator</tt> with given parameters.
     */
    public AttributeGenerator(double pGenerate, int numberOfNewAttributes, List generatorList) {
	this.pGenerate = pGenerate;
	this.numberOfNewAttributes = numberOfNewAttributes;
	this.generatorList = generatorList;
    }

    /** Determines the applicable generators and generatess up to
     *  <tt>numberOfNewAttributes</tt> new attributes. */
    public List operate(AttributeWeightedExampleSet exampleSet) throws Exception {
	//Ermittlung der anwendbaren Generatoren bzgl. des gegebenen ExampleSets 
	//int combinationSum = Tools.setArgumentCombinations(exampleSet, generatorList);
        ArrayList selectedGeneratorList = new ArrayList(); 
	
	for (int h = 0; h < numberOfNewAttributes ; h++){  
	    if (RandomGenerator.getGlobalRandomGenerator().nextDouble() < pGenerate) {
		
		//zufaellige Auswahl eines konkreten Generators aus der Menge der anwendbaren Generatoren
		FeatureGenerator selectedGenerator = FeatureGenerator.selectGenerator(exampleSet, generatorList, 0, new String[0]).newInstance();
		
		//Ermittlung der vom selektierten Generator geforderten Eingabe-Attribute
		Attribute[] arguments =  Tools.getRandomCompatibleAttributes(exampleSet, selectedGenerator, 0, new String[0]);
		selectedGenerator.setArguments(arguments);
		
		//selektierten FeatureGenerator in ArrayList einfuegen
		selectedGeneratorList.add(selectedGenerator);
	    }
	}
	//System.out.println("*** NEW GENERATION ***\n" + selectedGeneratorList);
	if (selectedGeneratorList.size() > 0) 
	    //Anwendung der ausgewaehlten Generatoren auf das aktuelle ExampleSet
	    exampleSet.addAllAttributes(FeatureGenerator.generateAll(exampleSet.getExampleTable(), selectedGeneratorList));
	List result = new LinkedList();
	result.add(exampleSet);
	return result;
    }
}