memoryexampletable.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;

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 2.16 2004/09/12 11:09:52 ingomierswa Exp $
 */
public class MemoryExampleTable extends ExampleTable {

    /** List of {@link DataRow}. */
    private LinkedList dataList = new LinkedList();

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

    /** Number of columns 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();
    }

    /** Creates a new instance of MemoryExampleTable.
     *  @param attributes List of {@link Attribute} containing the attributes of the columns.
     *                    None of these must be null.
     *  @param size initial size of this example table. All values will be Double.NaN.
     *  */
    public MemoryExampleTable(List attributes, int size) {
	this(attributes);
	dataList = new LinkedList();
	for (int i = 0; i < size; i++) {
	    double[] row = new double[columns];
	    for (int j = 0; j < row.length; j++) row[j] = Double.NaN;
	    dataList.add(new DoubleArrayDataRow(row));
	}
    }

    /** Creates an empty memory example table and fills it with the data rows read from i. */
    public MemoryExampleTable(List attributes, DataRowReader i) {
	this(attributes);
	readExamples(i);
    }

    /** Reads the examples into memory. */
    public void readExamples(DataRowReader i) {
	dataList = new LinkedList();
	
	boolean first = true;
	int numberOfAttributes = getNumberOfAttributes();
	while (i.hasNext()) {
	    DataRow row = i.next();
	    if (first && (row instanceof SparseMapDataRow)) {
		setSparse(true);
	    }
	    first = false;
	    dataList.add(row);
	}
    }

    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;
    }
}