蚁群算法代码

//Basic Ant Colony Algorithm for TSP
#include <iostream.h>
#include <fstream.h>
#include <math.h>
#include <time.h>
#include <conio.h>
#include <stdlib.h>
#include <iomanip.h>
#define N 31 //city size
#define M 31 //ant number
double inittao=1;
double tao[N][N];
double detatao[N][N];
double distance[N][N];
double yita[N][N];
int tabu[M][N];
int route[M][N];
double solution[M];
int BestRoute[N];
double BestSolution=10000000000;
double alfa,beta,rou,Q;
int NcMax;
void initparameter(void); // initialize the parameters of basic ACA
double EvalueSolution(int *a); // evaluate the solution of TSP, and calculate the length of path void InCityXY( double x[], double y[], char *infile ); // input the nodes' coordinates of TSP
void initparameter(void)
{
alfa=1; beta=5; rou=0.9; Q=100;
NcMax=200;
}
void main(void)
{
int NC=0;
initparameter();
double x[N];
double y[N];
InCityXY( x, y, "city31.tsp" );
for(int i=0;i<N;i++)
for(int j=i+1;j<N;j++)
{
distance[j][i]=sqrt((x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j])); distance[i][j]=distance[j][i];
}
// calculate the heuristic parameters
for(i=0;i<N;i++)
for(int j=0;j<N;j++)
{
tao[i][j]=inittao;
if(j!=i)
yita[i][j]=100/distance[i][j];
}
for(int k=0;k<M;k++)
for(i=0;i<N;i++)
route[k][i]=-1;
srand(time(NULL));
for(k=0;k<M;k++)
{
route[k][0]=k%N;
tabu[k][route[k][0]]=1;
}
//each ant try to find the optiamal path
do {
int s=1;
double partsum;
double pper;
double drand;
//ant choose one whole path
while(s<N)
{
for(k=0;k<M;k++)
{
int jrand=rand()%3000;
drand=jrand/3001.;
partsum=0;
pper=0;
for(int j=0;j<N;j++)
{
if(tabu[k][j]==0)
partsum+=pow(tao[route[k][s-1]][j],alfa)*pow(yita[route[k][s-1]][j],beta); }
for(j=0;j<N;j++)
{
if(tabu[k][j]==0)
pper+=pow(tao[route[k][s-1]][j],alfa)*pow(yita[route[k][s-1]][j],beta)/partsum; if(pper>drand)
break;
}
tabu[k][j]=1;
route[k][s]=j;
}
s++;
}
// the pheromone is updated
for(i=0;i<N;i++)
for(int j=0;j<N;j++)
detatao[i][j]=0;
for(k=0;k<M;k++)
{
solution[k]=EvalueSolution(route[k]);
if(solution[k]<BestSolution)
{
BestSolution=solution[k];
for(s=0;s<N;s++)
BestRoute[s]=route[k][s];
}
}
for(k=0;k<M;k++)
{
for(s=0;s<N-1;s++)
detatao[route[k][s]][route[k][s+1]]+=Q/solution[k];
detatao[route[k][N-1]][route[k][0]]+=Q/solution[k];
}
for(i=0;i<N;i++)
for(int j=0;j<N;j++)
{
tao[i][j]=rou*tao[i][j]+detatao[i][j];
if(tao[i][j]<0.00001)
tao[i][j]=0.00001;
if(tao[i][j]>20)
tao[i][j]=20;
}
for(k=0;k<M;k++)
for(int j=1;j<N;j++)
{
tabu[k][route[k][j]]=0;
route[k][j]=-1;
}
NC++;
} while(NC<NcMax);
//output the calculating results
fstream result;
result.open("optimal_results.log", ios::app);
if(!result)
{
cout<<"can't open the <optimal_results.log> file!\n";
exit(0);
}
result<<"*-------------------------------------------------------------------------*"<<endl; result<<"the initialized parameters of ACA are as follows:"<<endl;
result<<"alfa="<<alfa<<", beta="<<beta<<", rou="<<rou<<", Q="<<Q<<endl;
result<<"the maximum iteration number of ACA is:"<<NcMax<<endl;
result<<"the shortest length of the path is:"<<BestSolution<<endl;
result<<"the best route is:"<<endl;
for(i=0;i<N;i++)
result<<BestRoute[i]<<" ";
result<<endl;
result<<"*-------------------------------------------------------------------------*"<<endl<<endl; result.close();
cout<<"the shortest length of the path is:"<<BestSolution<<endl;
}
double EvalueSolution(int *a)
{
double dist=0;
for(int i=0;i<N-1;i++)
dist+=distance[a[i]][a[i+1]];
dist+=distance[a[i]][a[0]];
return dist;
}
void InCityXY( double x[], double y[], char *infile )
{
fstream inxyfile( infile, ios::in | ios::nocreate );
if( !inxyfile )
{
cout<<"can't open the <"<<infile<<"> file!\n";
exit(0);
}
int i=0;
while( !inxyfile.eof() )
{
inxyfile>>x[i]>>y[i];
if( ++i >= N ) break;
}
}
31个城市坐标：
1304 2312
3639 1315
4177 2244
3712 1399
3488 1535
3326 1556
3238 1229
4196 1004
4312 790
4386 570
3007 1970
2562 1756
2788 1491
2381 1676
1332 695
3715 1678
3918 2179
4061 2370
3780 2212
3676 2578
4029 2838
4263 2931
3429 1908
3507 2367
3394 2643
3439 3201
2935 3240
3140 3550
2545 2357
2778 2826
2370 2975
运行后可得到15602的巡游路径改正了n个错误。