JavaACOFramework的各个类介绍(part2 : Ant4AS类)

package aco.ant;

import java.util.ArrayList;

import util.RouletteWheel;//引入轮盘类
import aco.ACO;//引入蚁群类

/**
 * The AS Ant Class
 *
 * @author Thiago Nascimento
 * @since 2014-07-27
 * @version 1.0
 */
public class Ant4AS extends Ant {

   /*父类的构造函数*/
    public Ant4AS(ACO aco) {
        super(aco);
    }
  /*实现父类的explore结口，完成构造路径的工作*/
    @Override
    public void explore() {
        while (!nodesToVisit.isEmpty()) {
            int nextNode = doExploration(currentNode);//找到下一个访问的节点

            //Save next node
            tour.add(new Integer(nextNode));//将下一个节点的编号加入路径
            path[currentNode][nextNode] = 1;//将标志位矩阵中当前节点与下一节点间的边的访问标志置为1
            path[nextNode][currentNode] = 1;//将标志位矩阵中下一节点与当前节点间的边的访问标志置为1

            aco.p.updateTheMandatoryNeighborhood(this);//更新领域

            currentNode = nextNode;//把下一节点作为当前节点
        }
    }

    /**
     * 返回下一个访问节点的编号
     *
     * @param i ：当前节点的编号
     * @return 下一节点的编号，该函数是利用轮盘赌的方法选择下一个要访问的节点
     */
    protected int doExploration(int i) {
        int nextNode = -1;
        double sum = 0.0;

        // Update the sum
        for (Integer j : nodesToVisit) {
            if (aco.getTau(i, j) == 0.0) {
                throw new RuntimeException("tau == 0.0");
            }

            double tij = Math.pow(aco.getTau(i, j), ALPHA);
            double nij = Math.pow(aco.p.getNij(i, j), BETA);
            sum += tij * nij;
        }

        if (sum == 0.0) {
            throw new RuntimeException("sum == 0.0");
        }

        double[] probability = new double[aco.p.getNodes()];
        double sumProbability = 0.0;

        for (Integer j : nodesToVisit) {
            double tij = Math.pow(aco.getTau(i, j), ALPHA);
            double nij = Math.pow(aco.p.getNij(i, j), BETA);
            probability[j] = (tij * nij) / sum;
            sumProbability += probability[j];
        }

        // Select the next node by probability
        nextNode = RouletteWheel.select(probability, sumProbability);

        if (nextNode == -1) {
            throw new RuntimeException("nextNode == -1");
        }

        nodesToVisit.remove(new Integer(nextNode));

        return nextNode;
    }

    @Override 实现父类的clone接口，复制ant对象
    public Ant clone() {
        Ant ant = new Ant4AS(aco);
        ant.id = id;
        ant.currentNode = currentNode;
        ant.tourLength = tourLength;
        ant.tour = new ArrayList<Integer>(tour);
        ant.path = path.clone();
        return ant;
    }
}