TSP问题的遗传算法实现

这里贴出控制台版本的TSP_GA.cpp。

工程文件下载链接:http://download.csdn.net/source/2423693

TSP_GA.cpp如下：

#include <iostream>#include <fstream>#include <vector>#include <algorithm>#include <stdlib.h>#include <ctime>#include <assert.h>#include <cmath>using namespace std;struct Exchanger{int i,j;};//calculate length of a pathdouble calc_path_len(const vector<int>& path,const vector<vector<double> >& distance);//generate a integer sequence from 0 to n-1 at randomvoid rand_int_order(vector<int>& randorder,const int n);//operation: path add exchangervoid exch_add(vector<int>& path,Exchanger speed);//operation: path add exchange_sequencesvoid exch_add(vector<int>& path,const vector<Exchanger>& speed);//operation: exchange_sequences add exchange_sequencesvoid exch_add(vector<Exchanger>&speed_augend,const vector<Exchanger>& speed_addend,const unsigned int len);//multiplication for exchange sequencesvector<Exchanger> exch_multiply(const vector<Exchanger>&speed,const double accelerator);//subtraction for exchange sequencesvector<Exchanger> exch_sub(vector<int>&path_minuend,vector<int>&path_subtrahend);//calculate length of a pathdouble calc_path_len(const vector<int>& path,const vector<vector<double> >& distance){double dis=0;for (unsigned int i=0;i<path.size()-1;i++)dis+=distance[path[i]][path[i+1]];dis+=distance[path[path.size()-1]][path[0]];return dis;}//generate a integer sequence from 0 to n-1 at randomvoid rand_int_order(vector<int>& randorder,const int n) { assert(n>1); randorder.clear();randorder.resize(n);vector<int> recoder;for (int i=0;i<n;i++)recoder.push_back(i);for(int i=0;i<n;i++){int sel=rand()%recoder.size();randorder[i]=recoder[sel];recoder.erase(recoder.begin()+sel);}assert(randorder.size()==n);}//operation: path add exchangervoid exch_add(vector<int>& path,Exchanger speed){int t=path[speed.i];path[speed.i]=path[speed.j];path[speed.j]=t;}//operation: path add exchange_sequencesvoid exch_add(vector<int>& path,const vector<Exchanger>& speed){for (unsigned int i=0;i<speed.size();i++)exch_add(path,speed[i]);}//operation: exchange_sequences add exchange_sequencesvoid exch_add(vector<Exchanger>&speed_augend,const vector<Exchanger>& speed_addend,const unsigned int len){for (unsigned int i=0;i<speed_addend.size();i++)speed_augend.push_back(speed_addend[i]);//if the length of speed is too long,truncate it while(speed_augend.size()>len)speed_augend.erase(speed_augend.begin()+rand()%len);}//multiplication for exchange sequencesvector<Exchanger> exch_multiply(const vector<Exchanger>&speed,const double accelerator){vector<Exchanger> exch_v;//if accelerator is bigger than 1,copy (int)accelerator times of initial speed to new speedint dup=(int)accelerator;exch_v.resize(dup*speed.size());for (int i=0;i<dup;i++){copy(speed.begin(),speed.end(),exch_v.begin()+i*speed.size());}int copyLen=(int)((accelerator-dup)*speed.size());for (int i=0;i<copyLen;i++)exch_v.push_back(speed[i]);//if speed length is too long ,truncate itreturn exch_v;}//subtraction for exchange sequencesvector<Exchanger> exch_sub(vector<int>&path_minuend,vector<int>&path_subtrahend){vector<int> path_subtra=path_subtrahend;vector<Exchanger> exch_sub;for (unsigned int s=0;s<path_minuend.size();s++)if (path_minuend[s]!=path_subtrahend[s]){Exchanger ex;ex.i=find(path_subtra.begin()+s,path_subtra.end(),path_minuend[s])-path_subtra.begin();ex.j=s;exch_sub.push_back(ex);exch_add(path_subtra,ex);}return exch_sub;}//compress speed(exchange sequence),i.e. get the equivalent exchange_sequence//this function is not neccessory,but it might be more high-efficiencyvoid exch_compress(vector<Exchanger>& exch_sequence){}int main(){srand((unsigned)time(NULL));//read data from filefstream filein("data/in.txt",ios::in);if (filein==NULL){cout<<"cannot open data file"<<endl;return 1;}fstream fileout("data/result.txt",ios::out);if (fileout==NULL){cout<<"cannot open a file to write data"<<endl;return 1;}//append the best result found in this test to a file named "best.txt"fstream bestout("data/best.txt",ios::app);if (bestout==NULL){cout<<"cannot open a file to write data"<<endl;return 1;}//number of citiesunsigned int cityNum;filein>>cityNum;cout<<cityNum<<endl;//standard pathint* standardPath;standardPath=new int[cityNum+1];for (unsigned int i=0;i<cityNum;i++)standardPath[i]=i;//distance between citiesvector<vector<double> > distance;for (unsigned int i=0;i<cityNum;i++){vector<double> v;for (unsigned int j=0;j<cityNum;j++){double d;filein>>d;v.push_back(d);}distance.push_back(v);}////////////////////////////////////////////////////////////////////////////parameters//partical numberint partical_num=100;//partical swarmvector<vector<int> > swarm(partical_num);//acceleratordouble alpha=2;//if it equals to 1,accelerators will make no sense double beta=2;//inertiadouble inertia=1;//speed lengthint speed_len=cityNum/4;//global best particalvector<int> best_global(partical_num);//length of global best particaldouble best_global_len;//partial best particalsvector<vector<int> > best_partial;//length of partial best particalsvector<double> best_partial_len(partical_num);//speed of every particalvector<vector<Exchanger> >speed(partical_num);//initilization//particalsfor (int i=0;i<partical_num;i++)rand_int_order(swarm[i],cityNum);//initialize best partical lengthint l=1<<(8*sizeof(int)-2);best_global_len=l;for (int i=0;i<partical_num;i++)best_partial_len[i]=l;//best partial particalsbest_partial=swarm;//initialize speedfor (int i=0;i<partical_num;i++){int init_speed_len=rand()%speed_len;for (int j=0;j<init_speed_len;j++){Exchanger ex;ex.i=rand()%cityNum;ex.j=ex.i;while(ex.i=ex.j)ex.j=rand()%cityNum;speed[i].push_back(ex);}}//generation int generation=1000;for (int g=0;g<generation;g++){//update speed and best particals and length of these particalsdouble length;//find best of last generationint best_index_this=0;double best_len_this=1<<(8*sizeof(int)-2);for (int i=0;i<partical_num;i++){length=calc_path_len(swarm[i],distance);if (length<best_global_len){//update global best particalbest_global=swarm[i];best_global_len=length;best_partial[i]=swarm[i];best_partial_len[i]=length;}else if (length<best_partial_len[i]){//update partical best particalsbest_partial[i]=swarm[i];best_partial_len[i]=length;}if (length<best_len_this){best_len_this=length;best_index_this=i;}}fileout<<"generation "<<g<<" "<<endl<<"best path found in this generation:"<<endl;for (unsigned int i=0;i<cityNum;i++)fileout<<swarm[best_index_this][i]<<" ";fileout<<endl;fileout<<"best path length in this generation : "<<best_len_this<<endl;fileout<<"best path length found for the moment: "<<best_global_len<<endl;fileout<<endl;cout<<"generation :"<<g<<endl;cout<<"length in this generation :"<<best_len_this<<endl;cout<<"length found for the moment:"<<best_global_len<<endl;//shorten exchange sequences,i.e. speedfor (int i=0;i<partical_num;i++)exch_compress(speed[i]);for (int i=0;i<partical_num;i++){//update speedexch_add(exch_multiply(speed[i],inertia),exch_multiply(exch_sub(best_partial[i],swarm[i]),alpha*rand()/RAND_MAX),speed_len);exch_add(speed[i],exch_multiply(exch_sub(best_global,swarm[i]),beta*rand()/RAND_MAX),speed_len);//update particalsexch_add(swarm[i],exch_multiply(speed[i],inertia));}}//write best result found into a file bestout<<best_global_len<<endl;for (unsigned int i=0;i<cityNum;i++)bestout<<best_global[i]<<" ";bestout<<endl;//record timetime_t currenttime;time(¤ttime);bestout<<ctime(¤ttime);//show standard path and distancefileout<<"standard path:"<<endl;double standardbestlen=0;for (unsigned int i=0;i<cityNum;i++)fileout<<standardPath[i]<<" ";for (unsigned int i=0;i<cityNum-1;i++)standardbestlen+=distance[standardPath[i]][standardPath[i+1]];standardbestlen+=distance[standardPath[cityNum-1]][standardPath[0]];fileout<<endl<<"length of standard path: "<<endl<<""<<standardbestlen<<endl;//free memory/////////////////////////////////////////////////////////////filein.close();fileout.close();bestout.close();delete[] standardPath;return 0;}