singularnumericalgenerator.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.generator;

import edu.udo.cs.yale.tools.LogService;
import edu.udo.cs.yale.tools.Ontology;
import edu.udo.cs.yale.example.ExampleTable;
import edu.udo.cs.yale.example.Attribute;
import edu.udo.cs.yale.example.DataRow;
import edu.udo.cs.yale.example.ExampleSet;

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

/** Generators of this class will have one numerical input attribute and one output attribute. 
 *
 *  @version $Id: SingularNumericalGenerator.java,v 2.6 2004/08/27 11:57:33 ingomierswa Exp $
 */
public abstract class SingularNumericalGenerator extends FeatureGenerator {  

    private static final Attribute[] INPUT_ATTR = { new Attribute(Ontology.NUMERICAL, Ontology.SINGLE_VALUE) };

    public SingularNumericalGenerator() { }

    /** Subclasses have to implement this method to calculate the function result. */
    public abstract double calculateValue(double value);

    public Attribute[] getInputAttributes() {
	return INPUT_ATTR;
    }

    public Attribute[] getOutputAttributes(ExampleTable input) {
	Attribute a1 = getArgument(0);
	Attribute ao = new Attribute(Ontology.NUMERICAL, Ontology.SINGLE_VALUE,
				     getFunction(), new Attribute[] { a1 }, false,
				     //input.getNextFreeBlockNr(),
				     Attribute.UNDEFINED_BLOCK_NR,
				     null);
	return new Attribute[] { ao };
    }

//     /** Returns the number of attributes which matches the desired input attribute (numerical single value). */
//     public int getNumberOfApplicableGenerations(ExampleSet exampleSet) {
// 	int counter = 0;
// 	for (int i = 0; i < exampleSet.getNumberOfAttributes(); i++) {
// 	    Attribute attribute = exampleSet.getAttribute(i);
// 	    if (attribute.compatible(INPUT_ATTR[0])) counter++;
// 	}
// 	return counter;
//     }

    /** Returns all compatible input attribute arrays for this generator from the given example set as list. */
    public List getInputCandidates(ExampleSet exampleSet, int maxDepth, String[] functions) {
	List result = new ArrayList();
	for (int i = 0; i < exampleSet.getNumberOfAttributes(); i++) {
	    Attribute attribute = exampleSet.getAttribute(i);
	    if (checkCompatibility(attribute, INPUT_ATTR[0], maxDepth, functions))
		result.add(new Attribute[] { attribute });
	}
	return result;
    }

    public void generate(DataRow data) throws GenerationException {
	try {
  	    Attribute a = getArgument(0);
	    double value = data.get(a);
	    double r = calculateValue(value);
	    
	    if (Double.isInfinite(r)) {
		LogService.logMessage(getFunction() + ": Infinite value generated.", LogService.WARNING);
		throw new GenerationException(getFunction() + ": Infinite value generated.");
	    }
	    if (Double.isNaN(r)) {
		LogService.logMessage(getFunction() + ": NaN generated.", LogService.WARNING);
		throw new GenerationException(getFunction() + ": NaN generated.");
	    }
	    
	    if (resultAttributes[0] != null)
		data.set(resultAttributes[0], r);
	} catch (ArrayIndexOutOfBoundsException ex) {
  	    throw new GenerationException("a:" + getArgument(0), ex);
  	}
    }

    public String toString() {
	String s = "singular function ";
	if ((resultAttributes != null) && 
	    (resultAttributes.length > 0) &&
	    (resultAttributes[0] != null))
	    s += resultAttributes[0].getName()+":=";
	s += getFunction() + "(";
	if (argumentsSet()) s+=getArgument(0).getName();
	s += ")";
	return s;
    }
}