featureweights.java

著名的开源仿真软件yale

/*
 *  YALE - Yet Another Learning Environment
 *  Copyright (C) 2002, 2003
 *      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.features;

import edu.udo.cs.yale.operator.ResultObjectAdapter;
import edu.udo.cs.yale.operator.Saveable;

import java.io.*;
import java.util.Iterator;
import java.util.Map;
import java.util.LinkedHashMap;

/** FeatureWeights holds the information about the weights of attributes of an example set. It is delivered by
 *  several feature weighting algorithms.
 *
 *  @version $Id: FeatureWeights.java,v 2.1 2003/08/29 00:39:32 mierswa Exp $
 */
public class FeatureWeights extends ResultObjectAdapter implements Saveable {

    private Map weightMap = new LinkedHashMap();

    /** Adds a weight for the attribute with the given name. */
    public void addWeight(String name, double weight) {
	weightMap.put(name, new Double(weight));
    }

    /** Returns the weight for the attribute with the given name. Returns Double.NaN if the weight for the 
     *  queried attribute is not known. */
    public double getWeight(String name) {
	Double value = (Double)weightMap.get(name);
	if (value == null) return Double.NaN;
	else return value.doubleValue();
    }
    
    public void save(File file) throws IOException {	
	PrintWriter out = new PrintWriter(new FileWriter(file));
	Iterator i = weightMap.keySet().iterator();
	while (i.hasNext()) {
	    String key    = (String)i.next();
	    double weight = ((Double)weightMap.get(key)).doubleValue();
	    out.println(key + ": \t" + weight);
	}
	out.close();
    }

    public String toString() {
	StringBuffer result = new StringBuffer("");
	Iterator i = weightMap.keySet().iterator();
	while (i.hasNext()) {
	    String key = (String)i.next();
	    result.append(key + ": " + ((Double)weightMap.get(key)).doubleValue() + "\n");
	}
	return result.toString();
    }

    public static FeatureWeights load(File file) throws IOException {
	FeatureWeights result = new FeatureWeights();
	BufferedReader in = new BufferedReader(new FileReader(file));
	String line = null;
	while ((line = in.readLine()) != null) {
	    String name = line.substring(0, line.indexOf(":")).trim();
	    String weightString = line.substring(line.indexOf(":") + 1).trim();
	    double weight = 1.0d;
	    try {
		weight = Double.parseDouble(weightString);
	    } catch (NumberFormatException e) {
		throw new IOException("Cannot parse weight from weight file " + file + ": " + e.getMessage());
	    }
	    result.addWeight(name, weight);
	}
	in.close();
	return result;
    }
}