simplexlist.java

模拟退火是一种启发式算法

package org.theblueplanet.annealing;

import org.apache.log4j.Logger;

import java.util.ArrayList;

/**
 *  An ArrayList of Simplex Objects
 *
 * @see org.theblueplanet.annealing.Simplex
 *
 * @author     Charles M間nin
 * @since    October 29, 2001
 * @version    1.0
 */
public class SimplexList {
    private Logger logger = Logger.getLogger(this.getClass().toString());
    private ArrayList list;
    private final static double MAXVALUE = -1.0e100;

    /**
     *  Constructor for the SimplexList object
     *
     * @param  itol  Description of Parameter
     */
    public SimplexList(int itol) {
        this.list = new ArrayList(itol);
    }

    /**
     *  Gets the Index the Simplex with the maximum value field in the
     *  SimplexList
     *
     * @return    The index of the Simplex with the highest value field
     */
    public int getIndexOfMax() {
        double max  = MAXVALUE;
        int index   = -1;
        for (int ii = 0; ii < list.size(); ii++) {
            if (((Simplex) list.get(ii)).getValue() > max) {
                max = ((Simplex) list.get(ii)).getValue();
                index = ii;
            }
        }
        return index;
    }

    /**
     *  Gets the Index the Simplex with the minimum value field in the
     *  SimplexList
     *
     * @return    The index of the Simplex with the lowest value field
     */
    public Simplex getMinSimplex() {
        double min          = -MAXVALUE;
        Simplex minSimplex  = null;
        for (int ii = 0; ii < list.size(); ii++) {
            if (((Simplex) list.get(ii)).getValue() < min) {
                minSimplex = (Simplex) list.get(ii);
                min = ((Simplex) list.get(ii)).getValue();
            }
        }
        return minSimplex;
    }

    /**
     *  Add a Simplex object to the ArrayList
     *
     * @param  simplex  Description of Parameter
     */
    public void add(Simplex simplex) {
        list.add(simplex);
    }

    /**
     *  Computes the difference between the maximum and the minimum values of
     *  the elements of the SimplexList, <b>excluding the last Simplex added</b>
     *
     * @return    The spread
     */
    public double spread() {
        double max  = MAXVALUE;
        double min  = -max;
        for (int ii = 0; ii < list.size() - 1; ii++) {
            if (((Simplex) list.get(ii)).getValue() > max) {
                max = ((Simplex) list.get(ii)).getValue();
            }
            if (((Simplex) list.get(ii)).getValue() < min) {
                min = ((Simplex) list.get(ii)).getValue();
            }
        }
        return max - min;
    }

    /**
     *  Recursively calls the toScreen() method on all Simplex objects of the
     *  ArrayList
     *
     * @see org.theblueplanet.annealing.Simplex#toScreen()
     */
    public void toScreen() {
        for (int ii = 0; ii < list.size(); ii++) {
            ((Simplex) list.get(ii)).toScreen();
        }
    }

    /**
     *  Returns the size of the ArrayList
     *
     * @return    The number of Simplex objects in the SimplexList
     */
    public int size() {
        return list.size();
    }

    /**
     *  Removes a Simplex from the SimplexList
     *
     * @param  ii  The index of the Simplex to be removed
     */
    public void remove(int ii) {
        list.remove(ii);
    }

}