estimatedperformance.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.performance;

import edu.udo.cs.yale.tools.math.Averagable;
import edu.udo.cs.yale.example.Example;

/**
 * This class is used to store estimated performance values <b>before</b> an actual
 * performance test is done using a test set.
 * @version $Id: EstimatedPerformance.java,v 2.12 2004/08/27 11:57:43 ingomierswa Exp $
 */
public class EstimatedPerformance extends PerformanceCriterion {

    private String name;

    private double value;

    private double exampleCount = 1;

    private boolean reciprocalFitness;

    /** Clone constructor. */
    public EstimatedPerformance() {}

    /** Constructs a new extimated performance criterion.
     *  @param name Human readable name
     *  @param value The Value of the performance criterion
     *  @param numberOfExamples The number of examples used to estimate this value.
     *  @param reciprocalFitness Indicates whether or not the reciprocal value should be used as fitness value.
     */
    public EstimatedPerformance(String name, 
				double value, 
				int numberOfExamples,
				boolean reciprocalFitness) {
        this.name = name;
	setValue(value, numberOfExamples);
	this.reciprocalFitness = reciprocalFitness;
    }

    public double getVariance() { return Double.NaN; }

    /** Sets the value of this estimated performance criterion.
     *  @param value The Value of the performance criterion
     *  @param numberOfExamples The number of examples used to estimate this value. It is used
     *                          for calculateing the average. */
    public void setValue(double value, int numberOfExamples) {
	this.value        = value * numberOfExamples;
	this.exampleCount = numberOfExamples;
    }

    public double getValue() {
	return value / exampleCount;
    }

    /** Returns the fitness. */
    public double getFitness() { 
	if (reciprocalFitness) {
	    if (getValue() == 0d) return Double.POSITIVE_INFINITY;
	    return 1/getValue();
	} else {
	    return getValue();
	}
    }

    /**
     * Returns the name of this estimated performance criterion, which can be
     * set using <tt>setName()</tt>.
     *
     * @return The name.
     */
    public String getName()  { 
	return name; 
    }

    protected void cloneAveragable(Averagable other) {
	//super.cloneAveragable(other);
	EstimatedPerformance ep = (EstimatedPerformance)other;
	this.name               = ep.name;
	this.reciprocalFitness  = ep.reciprocalFitness;
	this.exampleCount       = ep.exampleCount;
	this.value              = ep.value;
    }

    public void buildAverage(Averagable performance) {
	super.buildAverage(performance);
	EstimatedPerformance other = (EstimatedPerformance)performance;
	if (!other.name.equals(this.name))
	    throw new RuntimeException("Cannot build average of different criterion types ("+this.getName()+"/"+other.getName()+").");
	this.exampleCount += other.exampleCount;
	this.value        += other.value;
    }
}