basicarithmeticoperationgenerator.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;

/** This class is a very simple implementation of a FeatureGenerator. It has two numerical input
 *  attributes and one output attribute. Depending on the mode specified in the constructor the
 *  result will be the sum, difference, product or quotient. The four modes are numered from 0 to 3
 *  int this order.
 *
 *  @author simon, ingo
 *  @version $Id: BasicArithmeticOperationGenerator.java,v 2.12 2004/08/27 11:57:32 ingomierswa Exp $
 */
public class BasicArithmeticOperationGenerator extends BinaryNumericalGenerator {  

    public static final int SUM        = 0;
    public static final int DIFFERENCE = 1;
    public static final int PRODUCT    = 2;
    public static final int QUOTIENT   = 3;

    public static final String[] FUNCTION_NAMES = { "+", "-", "*", "/" };

    private int mode;

    public BasicArithmeticOperationGenerator(int mode) {
	this.mode = mode;
    }

    public BasicArithmeticOperationGenerator() { }

    public boolean isSelfApplicable() {
	return mode == PRODUCT;
    }

    public boolean isCommutative() {
	return ((mode == PRODUCT) || (mode == SUM));
    }

    public FeatureGenerator newInstance() {
	return new BasicArithmeticOperationGenerator(mode);
    }

    public double calculateValue(double o1, double o2) { 
	double r = 0.0d;
	switch (mode) {
	    case SUM: r = o1 + o2; break;
	    case DIFFERENCE: r = o1 - o2; break;
	    case PRODUCT: r = o1 * o2; break;
	    case QUOTIENT: r = o1 / o2; break;
	}
	return r;
    }

    public void setFunction(String name) {
	for (int i = 0; i < FUNCTION_NAMES.length; i++) {
	    if (FUNCTION_NAMES[i].equals(name)) {
		this.mode = i;
		return;
	    }
	}
	LogService.logMessage("Illegal function name '"+name+"' for "+getClass().getName()+".", 
			      LogService.ERROR);
    }
    
    public String getFunction() {
	return FUNCTION_NAMES[mode];
    }

    public boolean equals(Object o) {
	return (super.equals(o) && (this.mode == ((BasicArithmeticOperationGenerator)o).mode));
    }
}