memoryexampletable.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.example;

import edu.udo.cs.yale.tools.LogService;

import java.io.File;
import java.io.IOException;
import java.io.StreamTokenizer;
import java.util.Iterator;
import java.util.List;
import java.util.LinkedList;

/** This class is the core data supplier for example sets.
 *  Several example sets can use the same data and access the attribute values
 *  by reference. In this case the data is hold in the main memory during the 
 *  experiment.
 *
 *  @author Simon, Ingo
 *  @version $Id: MemoryExampleTable.java,v 2.7 2003/09/10 13:02:06 fischer Exp $
 */
public class MemoryExampleTable extends ExampleTable {

    /** List of {@link DataRow}. */
    private LinkedList dataList = null;

    /** Number of columns. */
    private int columns;

    /** Number of clumns to add when new columns are allocated. */
    private static final int INCREMENT = 10;

    /** Creates a new instance of MemoryExampleTable.
     *  @param attributes List of {@link Attribute} containing the attributes of the columns.
     *                    None of these must be null.
     *  */
    public MemoryExampleTable(List attributes) {
	super(attributes);
	this.columns = attributes.size();
    }

    public MemoryExampleTable(List attributes, DataRowReader i) {
	this(attributes);
	readExamples(i);
    }

    /** Reads the examples into memory. */
    public void readExamples(DataRowReader i) {
	dataList = new LinkedList();
	double[] minimum = new double[columns];
	double[] maximum = new double[columns];
	double[] average = new double[columns];
	for (int n = 0; n < columns; n++) {
	    minimum[n] = Double.POSITIVE_INFINITY;
	    maximum[n] = Double.NEGATIVE_INFINITY;
	    average[n] = 0;
	}
	
	boolean first = true;
	int numberOfAttributes = getNumberOfAttributes();
	while (i.hasNext()) {
	    DataRow row = i.next();
	    if (first && (row instanceof SparseMapDataRow)) {
		setSparse(true);
	    }
	    first = false;
	    for (int n = 0; n < numberOfAttributes; n++) {
		Attribute attribute = getAttribute(n);
		if (!Double.isNaN(row.get(attribute))) {
		    double value = row.get(attribute);
		    if (minimum[n] > value) minimum[n] = value;
		    if (maximum[n] < value) maximum[n] = value;
		    average[n] += value;
		}
	    }
	    dataList.add(row);
	}

	for (int n = 0; n < getNumberOfAttributes(); n++) {
	    average[n] /= getSize();
	    Attribute attribute = getAttribute(n);
	    attribute.setMinimum(minimum[n]);
	    attribute.setMaximum(maximum[n]);
	    attribute.setAverage(average[n]);
	}
    }

    public DataRowReader getDataReader() {
	return new ListDataRowReader(dataList.iterator());
    }

    public int getSize() { 
	return dataList.size(); 
    }

    public int addAttribute(Attribute attribute) {
	int index = super.addAttribute(attribute);
	if (dataList == null) return index;
	int n = getNumberOfAttributes();
	if (n <= columns) return index;
	int newSize = n + INCREMENT;
	LogService.logMessage("Resizing example table from " + columns + " to " + 
			      newSize + " columns.", LogService.STATUS);
	columns = newSize;

	if (dataList != null) {
	    Iterator i = dataList.iterator();
	    while (i.hasNext())
		((DataRow)i.next()).ensureNumberOfColumns(columns);
	}
	return index;
    }
}