蚁群算法代码（C++）

//基本蚁群算法程序

#include "stdafx.h"
#include<iostream>

using namespace std;

const int iAntCount=34;//蚂蚁数量
const int iCityCount=51;//城市数量
const int iItCount=2000;//最大跌代次数
const double Q=100;
const double alpha=1;
const double beta=5;
const double rou=0.5;

int besttour[iCityCount];//最有路径列表

double  rnd(int low,double uper)//获得随机数
{

 double p=(rand()/(double)RAND_MAX)*((uper)-(low))+(low);

 return (p);

};

int rnd(int uper)
{
          return (rand()%uper);
};

class GInfo//tsp地图信息，包含了信息素，城市距离，和信息素变化矩阵
{

public:
 double m_dDeltTrial[iCityCount][iCityCount];
 double m_dTrial[iCityCount][iCityCount];
 double distance[iCityCount][iCityCount];

};

GInfo Map;

class ant
{

private:

 int ChooseNextCity();//选择城市
 double prob[iCityCount];
 int m_iCityCount;
 int AllowedCity[iCityCount];//没有走过的城市

public:

 void addcity(int city);
 int tabu[iCityCount];
 void Clear();
 void UpdateResult();
 double m_dLength;
 double m_dShortest;
 void move();
 ant();
 void move2last();

};
void ant::move2last()
{

 int i;
 for(i=0;i《iCityCount;i++)

  if (AllowedCity[i]==1)
  {
   addcity(i);
   break;
  }

}

void ant::Clear()
{
 m_dLength=0;
 int i;
 for(i=0;
 i〈iCityCount;i++)

  prob[i]=0;
  AllowedCity[i]=1;
 }
 i=tabu[iCityCount-1];
 m_iCityCount=0;
 addcity(i);
}
ant::ant()
{
 m_dLength=m_dShortest=0;
 m_iCityCount=0;
 int i;
 for(i=0;i〈iCityCount;i++)

  AllowedCity[i]=1;
  prob[i]=0;
 }
}
void ant::addcity(int city)
{
 //add city to tabu;
 tabu[m_iCityCount]=city;
 m_iCityCount++;
 AllowedCity[city]=0;
}
int ant::ChooseNextCity()
{
 //Update the probability of path selection
 //select a path from tabu[m_iCityCount-1] to next

 int i;
 int j=10000;
 double temp=0;
 int curCity=tabu[m_iCityCount-1];
 for (i=0;i〈iCityCount;i++)

  if((AllowedCity[i]==1)) 
  {
   temp+=pow((1.0/Map.distance[curCity][i]),beta)*pow((Map.m_dTrial[curCity][i]),alpha);
  }
 }
 double sel=0;
 for (i=0;i〈iCityCount;i++)

  if((AllowedCity[i]==1))
  {
   prob[i]=pow((1.0/Map.distance[curCity][i]),beta)*pow((Map.m_dTrial[curCity][i]),alpha)/temp;
   sel+=prob[i];
  }
  else
   prob[i]=0;
 }
 double mRate=rnd(0,sel);
 double mSelect=0;

 for ( i=0;i〈iCityCount;i++)

  if((AllowedCity[i]==1))
   mSelect+=prob[i] ;
  if (mSelect>=mRate) {j=i;break;}
 }

 if (j==10000)
 {
  temp=-1;
  for (i=0;i〈iCityCount;i++)

   if((AllowedCity[i]==1))
    if (temp
    {
     temp=pow((1.0/Map.distance[curCity][i]),beta)*pow((Map.m_dTrial[curCity][i]),alpha);
     j=i;
    }
  }
 }

 return j;

}
void ant::UpdateResult()
{
 // Update the length of tour
 int i;
 for(i=0;i〈iCityCount-1;i++)

       m_dLength+=Map.distance[tabu[i]][tabu[i+1]];
 m_dLength+=Map.distance[tabu[iCityCount-1]][tabu[0]];
}
void ant::move()
{
 //the ant move to next town and add town ID to tabu.
 int j;
 j=ChooseNextCity();
 addcity(j);
}
class project
{
public:

 void UpdateTrial();
 double m_dLength;
 void initmap();
 ant ants[iAntCount];
 void GetAnt();
 void StartSearch();
 project();
};
void project::UpdateTrial()
{
 //calculate the changes of trial information
 int i;
 int j;

 for(i=0;i〈iAntCount;i++)
  for (j=0;j〈iCityCount-1;j++)

{   Map.m_dDeltTrial[ants[i].tabu[j]][ants[i].tabu[j+1]]+=Q/ants[i].m_dLength ;
   Map.m_dDeltTrial[ants[i].tabu[j+1]][ants[i].tabu[j]]+=Q/ants[i].m_dLength;
  }
  Map.m_dDeltTrial[ants[i].tabu[iCityCount-1]][ants[i].tabu[0]]+=Q/ants[i].m_dLength;
  Map.m_dDeltTrial[ants[i].tabu[0]][ants[i].tabu[iCityCount-1]]+=Q/ants[i].m_dLength;
 }
 for (i=0;i〈iCityCount;i++)

  for (j=0;j〈iCityCount;j++)

  {
   Map.m_dTrial[i][j]=(rou*Map.m_dTrial[i][j]+Map.m_dDeltTrial[i][j] );
   Map.m_dDeltTrial[i][j]=0;
  }

 }

}
void project::initmap()
{
 int i;
 int j;
 for(i=0;i〈iCityCount;i++)
  for (j=0;j〈iCityCount;j++)
  {

   Map.m_dTrial[i][j]=1;
   Map.m_dDeltTrial[i][j]=0;
  }
}
project::project()
{
 //initial map,read map infomation from file . et.
 initmap();
 m_dLength=10e9;

 ifstream in("eil51.tsp");

 struct city
 {
  int num;
  int x;
  int  y;
 }cc[iCityCount];
 
 for (int i=0;i〈iCityCount;i++)
 {
  in>>cc[i].num>>cc[i].x>>cc[i].y;
  besttour[i]=0;
 }
 int j;
 for(i=0;i〈iCityCount;i++)
  for (j=0;j〈iCityCount;j++)
  {

   {
    Map.distance[i][j]=sqrt(pow((cc[i].x-cc[j].x),2)+pow((cc[i].y-cc[j].y),2));
   }
  }

}
void project::GetAnt()
{
 //randomly put ant into map
 int i=0;
 int city;
 srand( (unsigned)time( NULL ) +rand());
for (i=0;i〈iAntCount;i++)

 {
  city=rnd(iCityCount);
  ants[i].addcity(city);
 }

}
void project::StartSearch()
{
 //begin to find best solution
 int max=0;//every ant tours times
 int i;
 int j;
 double temp;
 int temptour[iCityCount];
 while ((max〈iItCount)

{  
  for(j=0;j〈iAntCount;j++)

  {
   for (i=0;i〈iCityCount-1;i++)

  ants[j].move();
  }

   for(j=0;j〈iAntCount;j++)
  {   ants[j].move2last();
   ants[j].UpdateResult ();
  }

  //find out the best solution of the step and put it into temp
  int t;
  temp=ants[0].m_dLength;
  for (t=0;t〈iCityCount;t++)
   temptour[t]=ants[0].tabu[t];
  for(j=0;j〈iAntCount;j++)
  {
   if (temp〉ants[j].m_dLength) {
    temp=ants[j].m_dLength;
    for ( t=0;t〈iCityCount;t++)
     temptour[t]=ants[j].tabu[t];
   }
  }

  if(temp〈m_dLength){
   m_dLength=temp;
   for ( t=0;t〈iCityCount;t++)
    besttour[t]=temptour[t];
  }
  printf("%d : %f/n",max,m_dLength);
  UpdateTrial(); 

  for(j=0;j〈iAntCount;j++)
   ants[j].Clear();

 

  max++;

 }
 printf("The shortest toure is : %f/n",m_dLength);

 for ( int t=0;t〈iCityCount;t++)
  printf(" %d ",besttour[t]);

}
int main()
{

 project TSP;
 TSP.GetAnt();
 TSP.StartSearch();
 return 0;
}

求eil51最优到了438，可以修改循环次数和其他参数。以得到更好的解。使用TSP数据的时候，将前面的一些字符串信息删除，只留下坐标数据。