skipnanexamplereader.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.example;

/** This ExampleReader skips all examples containing attribute values that are not a number.
 *
 *  @author Ingo, Simon
 *  @version $Id: SkipNANExampleReader.java,v 2.3 2004/08/27 11:57:32 ingomierswa Exp $
 */
public class SkipNANExampleReader implements ExampleReader {

    private ExampleReader reader;
    private Example currentExample;

    public SkipNANExampleReader(ExampleReader reader) {
	this.reader = reader;
	this.currentExample = null;
    }


    public boolean hasNext() {
	if (currentExample == null) {
	    while (reader.hasNext()) {
		Example e = reader.next();
		if (!containsNAN(e)) {
		    currentExample = e;
		    return true;
		}
	    }
	    return false;
	} else {
	    return true;
	}
    }

    public Example next() {
	hasNext();
	Example dummy = currentExample;
	currentExample = null;
	return dummy;
    }


    private boolean containsNAN(Example e) {
	for (int i = 0; i < e.getNumberOfAttributes(); i++) {
	    if (Double.isNaN(e.getValue(i))) return true;
	}
	return false;
    }

}