normalizedmatrixseries.java

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/* ======================================
 * JFreeChart : a free Java chart library
 * ======================================
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 * Project Lead:  David Gilbert ([e-mail]);
 *
 * (C) Copyright 2000-2003, by Object Refinery Limited and Contributors.
 *
 * This library is free software; you can redistribute it and/or modify it under the terms
 * of the GNU Lesser General Public License as published by the Free Software Foundation;
 * either version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with this
 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * ---------------------------
 * NormalizedMatrixSeries.java
 * ---------------------------
 * (C) Copyright 2003 by Barak Naveh and Contributors.
 *
 * Original Author:  Barak Naveh;;
 * Contributor(s):   David Gilbert (for Object Refinery Limited);
 *
 * $Id: NormalizedMatrixSeries.java,v 1.3 2003/09/03 15:08:51 mungady Exp $
 *
 * Changes
 * -------
 * 10-Jul-2003 : Version 1 contributed by Barak Naveh (DG);
 *
 */
 
package org.jfree.data;

/**
 * Represents a dense normalized matrix M[i,j] where each Mij item of the
 * matrix has a value (default is 0). When a matrix item is observed using
 * <code>getItem</code> method, it is normalized, that is, divided by the
 * total sum of all items. It can be also be scaled by setting a scale factor.
 *
 * @author Barak Naveh
 *
 * @since Jun 18, 2003
 */
public class NormalizedMatrixSeries extends MatrixSeries {
    
    /** The default scale factor. */
    public static final double DEFAULT_SCALE_FACTOR = 1.0;

    /**
     * A factor that multiplies each item in this series when observed using getItem method.
     */
    private double m_scaleFactor = DEFAULT_SCALE_FACTOR;

    /** The sum of all items in this matrix */
    private double m_totalSum;

    /**
     * Constructor for NormalizedMatrixSeries.
     *
     * @param name  the series name.
     * @param rows  the number of rows.
     * @param columns  the number of columns.
     */
    public NormalizedMatrixSeries(String name, int rows, int columns) {
        super(name, rows, columns);

        /*
         * we assum super is always initialized to all-zero matrix, so the
         * total sum should be 0 upon initialization. However, we set it to
         * Double.MIN_VALUE to get the same effect and yet avoid division by 0
         * upon initialization.
         */
        m_totalSum = Double.MIN_VALUE;
    }

    /**
     * Returns an item.
     * 
     * @param itemIndex  the index.
     * 
     * @return The value.
     * 
     * @see org.jfree.data.MatrixSeries#getItem(int)
     */
    public Number getItem(int itemIndex) {
        int    i = getItemRow(itemIndex);
        int    j = getItemColumn(itemIndex);

        double mij = get(i, j) * m_scaleFactor;
        Number n   = new Double(mij / m_totalSum);

        return n;
    }

    /**
     * Sets the factor that multiplies each item in this series when observed
     * using getItem mehtod.
     *
     * @param factor new factor to set.
     *
     * @see #DEFAULT_SCALE_FACTOR
     */
    public void setScaleFactor(double factor) {
        m_scaleFactor = factor;
    }


    /**
     * Returns the factor that multiplies each item in this series when
     * observed using getItem mehtod.
     *
     * @return the factor
     */
    public double getScaleFactor() {
        return m_scaleFactor;
    }


    /**
     * @see org.jfree.data.MatrixSeries#update(int, int, double)
     */
    public void update(int i, int j, double mij) {
        m_totalSum -= get(i, j);
        m_totalSum += mij;

        super.update(i, j, mij);
    }


    /**
     * @see org.jfree.data.MatrixSeries#zeroAll()
     */
    public void zeroAll() {
        m_totalSum = 0;
        super.zeroAll();
    }
}