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;

    }

}