missingvaluereplenishment.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.preprocessing;

import edu.udo.cs.yale.example.Attribute;

/** Replaces missing values in examples. If a value is missing, it is replaced by one of the
 *  functions "minimum", "maximum", "average", and "none", 
 *  which is applied to the non missing attribute values of the example set. "none" 
 *  means, that the value is not replaced. The function can be selected using the parameter list
 *  <code>columns</code>. If an attribute's name appears in this list as a key, the value is used 
 *  as the function name. If the attribute's name is not in the list, the function specified by
 *  the <code>default</code> parameter is used.
 *
 *  @yale.xmlclass MissingValueReplenishment
 *  @author Ingo, Simon
 *  @version $Id: MissingValueReplenishment.java,v 1.2 2004/08/27 11:57:44 ingomierswa Exp $
 */
public class MissingValueReplenishment extends ValueReplenishment {

    private static final int NONE    = 0;
    private static final int MINIMUM = 1;
    private static final int MAXIMUM = 2;
    private static final int AVERAGE = 3;
    private static final String[] REP_NAMES = { "none", "minimum", "maximum", "average" };

    public String[] getFunctionNames() { return REP_NAMES; }
    public int getDefaultFunction() { return NONE; }
    public int getDefaultColumnFunction() { return AVERAGE; }

    public boolean replenishValue(double currentValue) { 
	return Double.isNaN(currentValue); 
    }

    public double getReplenishmentValue(int functionIndex, Attribute attribute, double currentValue) {
	switch (functionIndex) {
	case NONE:
	    return currentValue;
	case MINIMUM:
	    return attribute.getMinimum();
	case MAXIMUM:
	    return attribute.getMaximum();
	case AVERAGE:
	    return attribute.getAverage();
	default:
	    throw new RuntimeException("Illegal value functionIndex: "+functionIndex);
	}
    }
}