• 模拟退火解决TSP问题


    // monituihuo.cpp : 定义控制台应用程序的入口点。
    //
    
    #include "stdafx.h"
    
    
    #include <stdio.h>
    #include <stdlib.h>
    #include <math.h>
    #include <time.h>
    #include <iostream>
    #include <fstream>
    #include <Windows.h>
    using namespace std;
    
    const int MAXN = 27; //城市数量
    const double MAX = 27.0; //城市数量
    const double INIT_T = 3000; //初始温度
    const double RATE = 0.95; //温度衰减率
    const double FINNAL_T = 1E-10; //终止温度
    const int IN_LOOP = 15000; //内循环次数
    const int LIMIT = 10000; //概率选择上限
    const int FINL_LOOP = 1000; //外层循环
    double DD=0;
    double D_Length[MAXN][MAXN]={0};
    
    struct path
    {//定义路线结构
        int citys[MAXN];
        double length;
    }D_BestPath;
    
    struct point
    {//定义点结构
        double x;
        double y;
    }D_Point[MAXN];
    
    
    //计算点和点之间的距离
    void point_dist()
    {
        int i, j;
        double x;
        for(i=0; i<MAXN; i++)
        {
            for(j=i+1; j<MAXN; j++)
            {
                x = (D_Point[i].x-D_Point[j].x)*(D_Point[i].x-D_Point[j].x);
                x += (D_Point[i].y-D_Point[j].y)*(D_Point[i].y-D_Point[j].y);
                D_Length[i][j] = sqrt(x);
                D_Length[j][i] = D_Length[i][j];
            }    
        }
    }
    //初始化
    void init()
    {
        int i;
        printf("初始状态路径:");
        D_BestPath.length = 0;
        for(i=0; i<MAXN; i++)
        {//初始顺序经过路径
            D_BestPath.citys[i] = i;
            printf("%d--", i);
        }
        for(i=0; i<MAXN-1; i++)
        {//计算路径长度
            D_BestPath.length += D_Length[i][i+1];
        }
        printf("
    路径长度为:%.3lf
    
    ", D_BestPath.length);
                
    }
    void Dprintf(path p)
    {//用于显示过程变化情况,打印
        int i;
        printf("路径是:");
        for(i=0; i<MAXN; i++)
        {
            printf("%d--", p.citys[i]);
        }
        printf("
    路径长度为:%.3lf
    
    ", p.length);
    }
    
    //输入城市坐标信息
    void input()
    {
        int i,ll = 1;
        ifstream f1("C:\city.txt",ios::in);
        for(i=0; i<MAXN; i++){
            if(ll % 2 != 0)
                f1 >> D_Point[i].x;
            if(ll % 2 == 0)
                f1 >> D_Point[i].y;
            ll++;
        }
        f1.close();
    }
    
    path getnext(path p)
    {
        path ret;
        int i,  x, y;
        int te;
        ret = p;
        do
        {
            x = (int)(MAX*rand()/(RAND_MAX + 1.0));
            y = (int)(MAX*rand()/(RAND_MAX + 1.0));
        }
        while(x == y);
        te = ret.citys[x];
        ret.citys[x] = ret.citys[y];
        ret.citys[y] = te;
        ret.length = 0;
        for(i=0; i<MAXN-1; i++)
        {//计算路径长度
            ret.length += D_Length[ret.citys[i]][ret.citys[i+1]];
        }
        Dprintf(ret);
        DD++;
        return ret;
    }
    
    void sa()
    {
        int i, P_L=0, P_F=0;;
        path curPath, newPath;
        double T = INIT_T;
        double p, delta;
        srand((int)time(0));
        curPath = D_BestPath;
        while(true)
        {
            for(i=0; i<IN_LOOP; i++)
            {
                newPath = getnext(curPath);
                delta = newPath.length - curPath.length;
                if(delta < 0)
                {//更新长度
                    curPath = newPath;
                    P_L = 0;
                    P_F = 0;
                }
                else
                {
                    p = (double)(1.0*rand()/(RAND_MAX+1.0));
                    if(exp(delta/T) < 1 && exp(delta/T) > p)
                    {
                        curPath = newPath;
                    }
                    P_L ++;
                }
                if(P_L > LIMIT)
                {
                    P_F ++;
                    break;
                }
            }
            if(curPath.length < newPath.length)
            {
                D_BestPath = curPath;
            }
            if(P_F > FINL_LOOP || T<FINNAL_T)
                break;
            T = T * RATE;
        }
    
    }
    
    void main()
    {
        input();
        point_dist();
        init();
        sa();
        Dprintf(D_BestPath);
        printf("
    共测试%.0lf次
    ", DD);
        system("pause");
    }

    参考:http://blog.csdn.net/oxoxzhu/article/details/8142306

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  • 原文地址:https://www.cnblogs.com/Key-Ky/p/3452511.html
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