driver.java

模拟退火是一种启发式算法

package org.theblueplanet.annealing;

import java.util.ArrayList;

import org.apache.log4j.Logger;

/**
 *  This is the middle layer between the UI and the algorithm. It runs the
 *  algorithm and maps the AnnealingScheme Object constructed by the
 *  UI client to a Schedule object.
 *  As of version 1.1 this runs in its own thread
 *
 * @author     Charles M間nin
 * @since    October 29, 2001
 * @version    1.1
 */
public class Driver implements Runnable {
    private final static int ITOL  = 10;
    private final static long idum = -64;
    private static Logger logger    = Logger.getLogger("org.theblueplanet.annealing");
    private AnnealingScheme scheme;
    private int loggerFrequency;

    public Driver(AnnealingScheme scheme, int loggerFrequency) {
        refresh(scheme);
        this.loggerFrequency = loggerFrequency;
        logger.debug("Logger frequency = " + loggerFrequency);
    }

    public void refresh(AnnealingScheme scheme) {
        this.scheme = scheme;
    }

    /**
     *  Main processing method for the Driver class
     *
     * @param  scheme                     The Object that encapsulates the annealing parameters
     * @exception  InstantiationException  Description of Exception
     * @exception  IllegalAccessException  Description of Exception
     * @exception  ClassNotFoundException  Description of Exception
     */
    public void run() {
        try {
        double ybb               = 1.0e+30;
        double temptr            = scheme.getTemperature();
        int iiter                = scheme.getNIterations();
        double coolingRate       = (double) scheme.getCoolingRate();
        Schedule schedule        = new Schedule(scheme);
        SimplexList simplexList  = new SimplexList(ITOL);
        Simplex simplex;
        logger.debug("Initializing annealing scheme with parameters\n" + scheme.toString());

        schedule.initializeP();

        int loopLevel = -1;
        for (; ; ) {
            loopLevel++;

            schedule.setPDiagonal();
            schedule.setY(scheme.getOffset());
            schedule.setYb(1.0e+30);
            int nit  = 0;

            for (int jiter = 1; jiter <= 100; jiter++) {
                schedule.setIter(iiter);
                //Anneal.amebsa(schedule, scheme.getTolerance(), temptr, idum);
                schedule.amebsa(scheme.getTolerance(), temptr, idum);
                temptr *= (100. - coolingRate) / 100.;
                nit += iiter - schedule.getIter();
                if (schedule.getYb() < ybb) {
                    ybb = schedule.getYb();
                }
                if (schedule.getIter() > 0) {
                    break;
                }
            }

            simplex = new Simplex(schedule.getPb(), schedule.getYb(), scheme.getNdim());

            //Display the best simplex every loggerFrequency time
            if(loggerFrequency != 0) {
                if (loopLevel % loggerFrequency == 0) {
                    logger.info("**** best solution iteration " + loopLevel);
                    simplexList.toScreen();
                    logger.info("****");
                }
            }

            if (simplexList.size() == ITOL) {
                simplexList.remove(simplexList.getIndexOfMax());
            }
            simplexList.add(simplex);
            if (simplexList.size() == ITOL) {
                if (simplexList.spread() < scheme.getTolerance()) {// Converged
                    logger.info("Solutions set:");
                    simplexList.toScreen();
                    logger.info("Best solution:");
                    simplexList.getMinSimplex().toScreen();
                    scheme.setOffset(simplexList.getMinSimplex().getVertex());
                    logger.info("***Converged with spread=" + simplexList.spread() + "***");
                    break;
                } else {
                    if (loggerFrequency != 0) {
                        if (loopLevel % loggerFrequency == 0) {
                            logger.info("***Spread=" + simplexList.spread() + "***");
                        }
                    }
                }
            }
        }
        } catch(Exception ie) {
            ie.printStackTrace();
        }
    }

}