java完成遺傳算法實例分享(打印城市信息)

import java.util.*;
public class Tsp { 
    private String cityName[]={"北京","上海","天津","重慶","哈爾濱","長春","沈陽","呼和浩特","石家莊","太原","濟南","鄭州","西安","蘭州","銀川","西寧","烏魯木齊","合肥","南京","杭州","長沙","南昌","武漢","成都","貴州","福建","台北","廣州","海口","南寧","昆明","拉薩","噴鼻港","澳門"};
    //private String cityEnd[]=new String[34];
    private int cityNum=cityName.length;     //城市個數
    private int popSize = 50;               //種群數目
    private int maxgens = 20000;            //迭代次數
    private double pxover = 0.8;            //穿插幾率
    private double pmultation = 0.05;       //變異幾率
    private long[][] distance = new long[cityNum][cityNum];
    private int range = 2000;               //用於斷定什麼時候停滯的數組區間
    private class genotype {
        int city[] = new int[cityNum];      //單個基因的城市序列
        long fitness;                      //該基因的順應度
        double selectP;                        //選擇幾率
        double exceptp;                        //希冀幾率
        int isSelected;                        //能否被選擇
    }
    private genotype[] citys = new genotype[popSize];
    /**
     *    結構函數，初始化種群
     */
    public Tsp() {
        for (int i = 0; i < popSize; i++) {
            citys[i] = new genotype();
            int[] num = new int[cityNum];
            for (int j = 0; j < cityNum; j++)
                num[j] = j;
            int temp = cityNum;
            for (int j = 0; j < cityNum; j++) {
                int r = (int) (Math.random() * temp);
                citys[i].city[j] = num[r];
                num[r] = num[temp - 1];
                temp--;
            }
            citys[i].fitness = 0;
            citys[i].selectP = 0;
            citys[i].exceptp = 0;
            citys[i].isSelected = 0;
        }
        initDistance();
    }
    /**
     *  盤算每一個種群每一個基因個別的順應度，選擇幾率，希冀幾率，和能否被選擇。
     */
    public void CalAll(){
        for( int i = 0; i< popSize; i++){
            citys[i].fitness = 0;
            citys[i].selectP = 0;
            citys[i].exceptp = 0;
            citys[i].isSelected = 0;
        }
        CalFitness();
        CalSelectP();
        CalExceptP();
        CalIsSelected();
    }
    /**
     *    填充，將多選的填充到未選的個別傍邊
     */
    public void pad(){
        int best = 0;
        int bad = 0;
        while(true){          
            while(citys[best].isSelected <= 1 && best<popSize-1)
                best ++;
            while(citys[bad].isSelected != 0 && bad<popSize-1)
                bad ++;
            for(int i = 0; i< cityNum; i++)
                citys[bad].city[i] = citys[best].city[i];
                citys[best].isSelected --;
                citys[bad].isSelected ++;
                bad ++;  
            if(best == popSize ||bad == popSize)
                break;
        }
    }
    /**
     *    穿插主體函數
     */
    public void crossover() {
        int x;
        int y;
        int pop = (int)(popSize* pxover /2);
        while(pop>0){
            x = (int)(Math.random()*popSize);
            y = (int)(Math.random()*popSize);
            executeCrossover(x,y);//x y 兩個別履行穿插
            pop--;
        }
    }
    /**
     * 履行穿插函數
     * @param 個別x
     * @param 個別y
     * 對個別x和個別y履行佳點集的穿插，從而發生下一代城市序列
     */
    private void executeCrossover(int x,int y){
        int dimension = 0;
        for( int i = 0 ;i < cityNum; i++)
            if(citys[x].city[i] != citys[y].city[i]){
                dimension ++;
            } 
        int diffItem = 0;
        double[] diff = new double[dimension];
        for( int i = 0 ;i < cityNum; i++){
            if(citys[x].city[i] != citys[y].city[i]){
                diff[diffItem] = citys[x].city[i];
                citys[x].city[i] = -1;
                citys[y].city[i] = -1;
                diffItem ++;
            } 
        }
        Arrays.sort(diff);
        double[] temp = new double[dimension];
        temp = gp(x, dimension);
        for( int k = 0; k< dimension;k++)
            for( int j = 0; j< dimension; j++)
                if(temp[j] == k){
                    double item = temp[k];
                    temp[k] = temp[j];
                    temp[j] = item;
                    item = diff[k];
                    diff[k] = diff[j];
                    diff[j] = item; 
                }
        int tempDimension = dimension;
        int tempi = 0;
        while(tempDimension> 0 ){
            if(citys[x].city[tempi] == -1){
                citys[x].city[tempi] = (int)diff[dimension - tempDimension];
                tempDimension --;
            } 
            tempi ++;
        }
        Arrays.sort(diff);
        temp = gp(y, dimension);
        for( int k = 0; k< dimension;k++)
            for( int j = 0; j< dimension; j++)
                if(temp[j] == k){
                    double item = temp[k];
                    temp[k] = temp[j];
                    temp[j] = item;
                    item = diff[k];
                    diff[k] = diff[j];
                    diff[j] = item; 
                }
        tempDimension = dimension;
        tempi = 0;
        while(tempDimension> 0 ){
            if(citys[y].city[tempi] == -1){
                citys[y].city[tempi] = (int)diff[dimension - tempDimension];
                tempDimension --;
            } 
            tempi ++;
        }
    }
    /**
     * @param individual 個別
     * @param dimension    維數
     * @return 佳點集   (用於穿插函數的穿插點）    在executeCrossover()函數中應用
     */
    private double[] gp(int individual, int dimension){
        double[] temp = new double[dimension];
        double[] temp1 = new double[dimension];
        int p = 2 * dimension + 3;
        while(!isSushu(p))
            p++;
        for( int i = 0; i< dimension; i++){
            temp[i] = 2*Math.cos(2*Math.PI*(i+1)/p) * (individual+1);
            temp[i] = temp[i] - (int)temp[i];
            if( temp [i]< 0)
                temp[i] = 1+temp[i];
        }
        for( int i = 0; i< dimension; i++)
            temp1[i] = temp[i];
        Arrays.sort(temp1);
        //排序
        for( int i = 0; i< dimension; i++)
            for( int j = 0; j< dimension; j++)
                if(temp[j]==temp1[i])
                    temp[j] = i;
        return temp;
    }
    /**
     *    變異
     */
    public void mutate(){
        double random;
        int temp;
        int temp1;
        int temp2;
        for( int i = 0 ; i< popSize; i++){
            random = Math.random();
            if(random<=pmultation){
                temp1 = (int)(Math.random() * (cityNum));
                temp2 = (int)(Math.random() * (cityNum));
                temp = citys[i].city[temp1];
                citys[i].city[temp1] = citys[i].city[temp2];
                citys[i].city[temp2] = temp;
            }
        }     
    }
    /**
     * 打印以後代數的一切城市序列，和其相干的參數
     */
    public void print(){
    /**
     * 初始化各城市之間的間隔
     */
    private void initDistance(){
        for (int i = 0; i < cityNum; i++) {
            for (int j = 0; j < cityNum; j++){
                distance[i][j] = Math.abs(i-j);
            }
        }
    }
    /**
     * 盤算一切城市序列的順應度
     */
    private void CalFitness() {
        for (int i = 0; i < popSize; i++) {
            for (int j = 0; j < cityNum - 1; j++)
                citys[i].fitness += distance[citys[i].city[j]][citys[i].city[j + 1]];
            citys[i].fitness += distance[citys[i].city[0]][citys[i].city[cityNum - 1]];
        }
    }
    /**
     * 盤算選擇幾率
     */
    private void CalSelectP(){
        long sum = 0;
        for( int i = 0; i< popSize; i++)
            sum += citys[i].fitness;
        for( int i = 0; i< popSize; i++)
            citys[i].selectP = (double)citys[i].fitness/sum;
    }
    /**
     * 盤算希冀幾率
     */
    private void CalExceptP(){
        for( int i = 0; i< popSize; i++)
            citys[i].exceptp = (double)citys[i].selectP * popSize;
    }
    /**
     * 盤算該城市序列能否較優，較優則被選擇，進入下一代
     */
    private void CalIsSelected(){
        int needSelecte = popSize;
        for( int i = 0; i< popSize; i++)
            if( citys[i].exceptp<1){
                citys[i].isSelected++;
                needSelecte --;
            }
        double[] temp = new double[popSize];
        for (int i = 0; i < popSize; i++) {
//          temp[i] = citys[i].exceptp - (int) citys[i].exceptp;
//          temp[i] *= 10;
            temp[i] = citys[i].exceptp*10;
        }
        int j = 0;
        while (needSelecte != 0) {
            for (int i = 0; i < popSize; i++) {
                if ((int) temp[i] == j) {
                    citys[i].isSelected++;
                    needSelecte--;
                    if (needSelecte == 0)
                        break;
                }
            }
            j++;
        }
    }
    /**
     * @param x
     * @return 斷定一個數能否是素數的函數
     */
    private boolean isSushu( int x){
           if(x<2) return false;
           for(int i=2;i<=x/2;i++)
           if(x%i==0&&x!=2) return false;
           return true;
        }
    /**
     * @param x 數組
     * @return x數組的值能否全體相等，相等則表現x.length代的最優成果雷同，則算法停止
     */
    private boolean isSame(long[] x){
        for( int i = 0; i< x.length -1; i++)
            if(x[i] !=x[i+1])
                return false;
        return true;
    }
    /**
     * 打印隨意率性代最優的途徑序列
     */
    private void printBestRoute(){
        CalAll();
        long temp = citys[0].fitness;
        int index = 0;
        for (int i = 1; i < popSize; i++) {
            if(citys[i].fitness<temp){
                temp = citys[i].fitness;
                index = i;
            }
        }
        System.out.println();
        System.out.println("最好途徑的序列：");
        for (int j = 0; j < cityNum; j++)
        {
            String cityEnd[]={cityName[citys[index].city[j]]};
            for(int m=0;m<cityEnd.length;m++)
            {
                System.out.print(cityEnd[m] + " ");
            }
        }
            //System.out.print(citys[index].city[j] + cityName[citys[index].city[j]] + "  ");
            //System.out.print(cityName[citys[index].city[j]]);
        System.out.println();
    }
    /**
     * 算法履行
     */
    public void run(){
        long[] result = new long[range];
        //result初始化為一切的數字都不相等
        for( int i  = 0; i< range; i++)
            result[i] = i;
        int index = 0;       //數組中的地位
        int num = 1;     //第num代
        while(maxgens>0){
            System.out.println("-----------------  第  "+num+" 代  -------------------------");
            CalAll();
            print();
            pad();
            crossover();
            mutate();
            maxgens --;
            long temp = citys[0].fitness;
            for ( int i = 1; i< popSize; i++)
                if(citys[i].fitness<temp){
                    temp = citys[i].fitness;
                }
            System.out.println("最優的解："+temp);
            result[index] = temp;
            if(isSame(result))
                break;
            index++;
            if(index==range)
                index = 0;
            num++;
        }
        printBestRoute();
    }
    /**
     * @param a 開端時光
     * @param b   停止時光
     */
    public void CalTime(Calendar a,Calendar b){
        long x = b.getTimeInMillis() - a.getTimeInMillis();
        long y = x/1000;
        x = x - 1000*y;
        System.out.println("算法履行時光："+y+"."+x+" 秒");
    }
    /**
     *    法式進口
     */
    public static void main(String[] args) {
        Calendar a = Calendar.getInstance(); //開端時光
        Tsp tsp = new Tsp();
        tsp.run();
        Calendar b = Calendar.getInstance(); //停止時光
        tsp.CalTime(a, b);
    }
}