本文实例讲述了C++实现简单遗传算法。分享给大家供大家参考。具体实现方法如下:
// CMVSOGA.h : main header file for the CMVSOGA.cpp
////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////
#if !defined(AFX_CMVSOGA_H__45BECA_61EB_4A0E_9746_9A94D1CCF767__INCLUDED_)
#define AFX_CMVSOGA_H__45BECA_61EB_4A0E_9746_9A94D1CCF767__INCLUDED_
#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
#include "Afxtempl.h"
#define variablenum 14
class CMVSOGA
{
public:
CMVSOGA();
~CMVSOGA();
void selectionoperator();
void crossoveroperator();
void mutationoperator();
void initialpopulation(int, int ,double ,double,double *,double *); //种群初始化
void generatenextpopulation(); //生成下一代种群
void evaluatepopulation(); //评价个体,求最佳个体
void calculateobjectvalue(); //计算目标函数值
void calculatefitnessvalue(); //计算适应度函数值
void findbestandworstindividual(); //寻找最佳个体和最差个体
void performevolution();
void GetResult(double *);
void GetPopData(CList <double,double>&);
void SetFitnessData(CList <double,double>&,CList <double,double>&,CList <double,double>&);
private:
struct individual
{
double chromosome[variablenum]; //染色体编码长度应该为变量的个数
double value;
double fitness; //适应度
};
double variabletop[variablenum]; //变量值
double variablebottom[variablenum]; //变量值
int popsize; //种群大小
// int generation; //世代数
int best_index;
int worst_index;
double crossoverrate; //交叉率
double mutationrate; //变异率
int maxgeneration; //最大世代数
struct individual bestindividual; //最佳个体
struct individual worstindividual; //最差个体
struct individual current; //当前个体
struct individual current1; //当前个体
struct individual currentbest; //当前最佳个体
CList <struct individual,struct individual &> population; //种群
CList <struct individual,struct individual &> newpopulation; //新种群
CList <double,double> cfitness; //存储适应度值
//怎样使链表的数据是一个结构体????主要是想把种群作成链表。节省空间。
};
#endif
执行文件:
// CMVSOGA.cpp : implementation file
//
#include "stdafx.h"
//#include "vld.h"
#include "CMVSOGA.h"
#include "math.h"
#include "stdlib.h"
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif
/////////////////////////////////////////////////////////////////////////////
// CMVSOGA.cpp
CMVSOGA::CMVSOGA()
{
best_index=0;
worst_index=0;
crossoverrate=0; //交叉率
mutationrate=0; //变异率
maxgeneration=0;
}
CMVSOGA::~CMVSOGA()
{
best_index=0;
worst_index=0;
crossoverrate=0; //交叉率
mutationrate=0; //变异率
maxgeneration=0;
population.RemoveAll(); //种群
newpopulation.RemoveAll(); //新种群
cfitness.RemoveAll();
}
void CMVSOGA::initialpopulation(int ps, int gen ,double cr ,double mr,double *xtop,double *xbottom) //第一步,初始化。
{
//应该采用一定的策略来保证遗传算法的初始化合理,采用产生正态分布随机数初始化?选定中心点为多少?
int i,j;
popsize=ps;
maxgeneration=gen;
crossoverrate=cr;
mutationrate =mr;
for (i=0;i<variablenum;i++)
{
variabletop[i] =xtop[i];
variablebottom[i] =xbottom[i];
}
//srand( (unsigned)time( NULL ) ); //寻找一个真正的随机数生成函数。
for(i=0;i<popsize;i++)
{
for (j=0;j<variablenum ;j++)
{
current.chromosome[j]=double(rand()%10000)/10000*(variabletop[j]-variablebottom[j])+variablebottom[j];
}
current.fitness=0;
current.value=0;
population.InsertAfter(population.FindIndex(i),current);//除了初始化使用insertafter外,其他的用setat命令。
}
}
void CMVSOGA::generatenextpopulation()//第三步,生成下一代。
{
//srand( (unsigned)time( NULL ) );
selectionoperator();
crossoveroperator();
mutationoperator();
}
//void CMVSOGA::evaluatepopulation() //第二步,评价个体,求最佳个体
//{
// calculateobjectvalue();
// calculatefitnessvalue(); //在此步中因该按适应度值进行排序.链表的排序.
// findbestandworstindividual();
//}
void CMVSOGA:: calculateobjectvalue() //计算函数值,应该由外部函数实现。主要因为目标函数很复杂。
{
int i,j;
double x[variablenum];
for (i=0; i<popsize; i++)
{
current=population.GetAt(population.FindIndex(i));
current.value=0;
//使用外部函数进行,在此只做结果的传递。
for (j=0;j<variablenum;j++)
{
x[j]=current.chromosome[j];
current.value=current.value+(j+1)*pow(x[j],4);
}
////使用外部函数进行,在此只做结果的传递。
population.SetAt(population.FindIndex(i),current);
}
}
void CMVSOGA::mutationoperator() //对于浮点数编码,变异算子的选择具有决定意义。
//需要guass正态分布函数,生成方差为sigma,均值为浮点数编码值c。
{
// srand((unsigned int) time (NULL));
int i,j;
double r1,r2,p,sigma;//sigma高斯变异参数
for (i=0;i<popsize;i++)
{
current=population.GetAt(population.FindIndex(i));
//生成均值为current.chromosome,方差为sigma的高斯分布数
for(j=0; j<variablenum; j++)
{
r1 = double(rand()%10001)/10000;
r2 = double(rand()%10001)/10000;
p = double(rand()%10000)/10000;
if(p<mutationrate)
{
double sign;
sign=rand()%2;
sigma=0.01*(variabletop[j]-variablebottom [j]);
//高斯变异
if(sign)
{
current.chromosome[j] = (current.chromosome[j]
+ sigma*sqrt(-2*log(r1)/0.4323)*sin(2*3.1415926*r2));
}
else
{
current.chromosome[j] = (current.chromosome[j]
- sigma*sqrt(-2*log(r1)/0.4323)*sin(2*3.1415926*r2));
}
if (current.chromosome[j]>variabletop[j])
{
current.chromosome[j]=double(rand()%10000)/10000*(variabletop[j]-variablebottom[j])+variablebottom[j];
}
if (current.chromosome[j]<variablebottom [j])
{
current.chromosome[j]=double(rand()%10000)/10000*(variabletop[j]-variablebottom[j])+variablebottom[j];
}
}
}
population.SetAt(population.FindIndex(i),current);
}
}
void CMVSOGA::selectionoperator() //从当前个体中按概率选择新种群,应该加一个复制选择,提高种群的平均适应度
{
int i,j,pindex=0;
double p,pc,sum;
i=0;
j=0;
pindex=0;
p=0;
pc=0;
sum=0.001;
newpopulation.RemoveAll();
cfitness.RemoveAll();
//链表排序
// population.SetAt (population.FindIndex(0),current); //多余代码
for (i=1;i<popsize;i++)
{
current=population.GetAt(population.FindIndex(i));
for(j=0;j<i;j++) //从小到大用before排列。
{
current1=population.GetAt(population.FindIndex(j));//临时借用变量
if(current.fitness<=current1.fitness)
{
population.InsertBefore(population.FindIndex(j),current);
population.RemoveAt(population.FindIndex(i+1));
break;
}
}
// m=population.GetCount();
}
//链表排序
for(i=0;i<popsize;i++)//求适应度总值,以便归一化,是已经排序好的链。
{
current=population.GetAt(population.FindIndex(i)); //取出来的值出现问题.
sum+=current.fitness;
}
for(i=0;i<popsize; i++)//归一化
{
current=population.GetAt(population.FindIndex(i)); //population 有值,为什么取出来的不正确呢??
current.fitness=current.fitness/sum;
cfitness.InsertAfter (cfitness .FindIndex(i),current.fitness);
}
for(i=1;i<popsize; i++)//概率值从小到大;
{
current.fitness=cfitness.GetAt (cfitness.FindIndex(i-1))
+cfitness.GetAt(cfitness.FindIndex(i)); //归一化
cfitness.SetAt (cfitness .FindIndex(i),current.fitness);
population.SetAt(population.FindIndex(i),current);
}
for (i=0;i<popsize;)//轮盘赌概率选择。本段还有问题。
{
p=double(rand()%999)/1000+0.0001; //随机生成概率
pindex=0; //遍历索引
pc=cfitness.GetAt(cfitness.FindIndex(1)); //为什么取不到数值???20060910
while(p>=pc&&pindex<popsize) //问题所在。
{
pc=cfitness.GetAt(cfitness .FindIndex(pindex));
pindex++;
}
//必须是从index~popsize,选择高概率的数。即大于概率p的数应该被选择,选择不满则进行下次选择。
for (j=popsize-1;j<pindex&&i<popsize;j--)
{
newpopulation.InsertAfter (newpopulation.FindIndex(0),
population.GetAt (population.FindIndex(j)));
i++;
}
}
for(i=0;i<popsize; i++)
{
population.SetAt (population.FindIndex(i),
newpopulation.GetAt (newpopulation.FindIndex(i)));
}
// j=newpopulation.GetCount();
// j=population.GetCount();
newpopulation.RemoveAll();
}
//current 变化后,以上没有问题了。
void CMVSOGA:: crossoveroperator() //非均匀算术线性交叉,浮点数适用,alpha ,beta是(0,1)之间的随机数
//对种群中两两交叉的个体选择也是随机选择的。也可取beta=1-alpha;
//current的变化会有一些改变。
{
int i,j;
double alpha,beta;
CList <int,int> index;
int point,temp;
double p;
// srand( (unsigned)time( NULL ) );
for (i=0;i<popsize;i++)//生成序号
{
index.InsertAfter (index.FindIndex(i),i);
}
for (i=0;i<popsize;i++)//打乱序号
{
point=rand()%(popsize-1);
temp=index.GetAt(index.FindIndex(i));
index.SetAt(index.FindIndex(i),
index.GetAt(index.FindIndex(point)));
index.SetAt(index.FindIndex(point),temp);
}
for (i=0;i<popsize-1;i+=2)
{//按顺序序号,按序号选择两个母体进行交叉操作。
p=double(rand()%10000)/10000.0;
if (p<crossoverrate)
{
alpha=double(rand()%10000)/10000.0;
beta=double(rand()%10000)/10000.0;
current=population.GetAt(population.FindIndex(index.GetAt(index.FindIndex(i))));
current1=population.GetAt(population.FindIndex(index.GetAt(index.FindIndex(i+1))));//临时使用current1代替
for(j=0;j<variablenum;j++)
{
//交叉
double sign;
sign=rand()%2;
if(sign)
{
current.chromosome[j]=(1-alpha)*current.chromosome[j]+
beta*current1.chromosome[j];
}
else
{
current.chromosome[j]=(1-alpha)*current.chromosome[j]-
beta*current1.chromosome[j];
}
if (current.chromosome[j]>variabletop[j]) //判断是否超界.
{
current.chromosome[j]=double(rand()%10000)/10000*(variabletop[j]-variablebottom[j])+variablebottom[j];
}
if (current.chromosome[j]<variablebottom [j])
{
current.chromosome[j]=double(rand()%10000)/10000*(variabletop[j]-variablebottom[j])+variablebottom[j];
}
if(sign)
{
current1.chromosome[j]=alpha*current.chromosome[j]+
(1- beta)*current1.chromosome[j];
}
else
{
current1.chromosome[j]=alpha*current.chromosome[j]-
(1- beta)*current1.chromosome[j];
}
if (current1.chromosome[j]>variabletop[j])
{
current1.chromosome[j]=double(rand()%10000)/10000*(variabletop[j]-variablebottom[j])+variablebottom[j];
}
if (current1.chromosome[j]<variablebottom [j])
{
current1.chromosome[j]=double(rand()%10000)/10000*(variabletop[j]-variablebottom[j])+variablebottom[j];
}
}
//回代
}
newpopulation.InsertAfter (newpopulation.FindIndex(i),current);
newpopulation.InsertAfter (newpopulation.FindIndex(i),current1);
}
ASSERT(newpopulation.GetCount()==popsize);
for (i=0;i<popsize;i++)
{
population.SetAt (population.FindIndex(i),
newpopulation.GetAt (newpopulation.FindIndex(i)));
}
newpopulation.RemoveAll();
index.RemoveAll();
}
void CMVSOGA:: findbestandworstindividual( )
{
int i;
bestindividual=population.GetAt(population.FindIndex(best_index));
worstindividual=population.GetAt(population.FindIndex(worst_index));
for (i=1;i<popsize; i++)
{
current=population.GetAt(population.FindIndex(i));
if (current.fitness>bestindividual.fitness)
{
bestindividual=current;
best_index=i;
}
else if (current.fitness<worstindividual.fitness)
{
worstindividual=current;
worst_index=i;
}
}
population.SetAt(population.FindIndex(worst_index),
population.GetAt(population.FindIndex(best_index)));
//用最好的替代最差的。
if (maxgeneration==0)
{
currentbest=bestindividual;
}
else
{
if(bestindividual.fitness>=currentbest.fitness)
{
currentbest=bestindividual;
}
}
}
void CMVSOGA:: calculatefitnessvalue() //适应度函数值计算,关键是适应度函数的设计
//current变化,这段程序变化较大,特别是排序。
{
int i;
double temp;//alpha,beta;//适应度函数的尺度变化系数
double cmax=100;
for(i=0;i<popsize;i++)
{
current=population.GetAt(population.FindIndex(i));
if(current.value<cmax)
{
temp=cmax-current.value;
}
else
{
temp=0.0;
}
/*
if((population[i].value+cmin)>0.0)
{temp=cmin+population[i].value;}
else
{temp=0.0;
}
*/
current.fitness=temp;
population.SetAt(population.FindIndex(i),current);
}
}
void CMVSOGA:: performevolution() //演示评价结果,有冗余代码,current变化,程序应该改变较大
{
if (bestindividual.fitness>currentbest.fitness)
{
currentbest=population.GetAt(population.FindIndex(best_index));
}
else
{
population.SetAt(population.FindIndex(worst_index),currentbest);
}
}
void CMVSOGA::GetResult(double *Result)
{
int i;
for (i=0;i<variablenum;i++)
{
Result[i]=currentbest.chromosome[i];
}
Result[i]=currentbest.value;
}
void CMVSOGA::GetPopData(CList <double,double>&PopData)
{
PopData.RemoveAll();
int i,j;
for (i=0;i<popsize;i++)
{
current=population.GetAt(population.FindIndex(i));
for (j=0;j<variablenum;j++)
{
PopData.AddTail(current.chromosome[j]);
}
}
}
void CMVSOGA::SetFitnessData(CList <double,double>&PopData,CList <double,double>&FitnessData,CList <double,double>&ValueData)
{
int i,j;
for (i=0;i<popsize;i++)
{
current=population.GetAt(population.FindIndex(i)); //就因为这一句,出现了很大的问题。
for (j=0;j<variablenum;j++)
{
current.chromosome[j]=PopData.GetAt(PopData.FindIndex(i*variablenum+j));
}
current.fitness=FitnessData.GetAt(FitnessData.FindIndex(i));
current.value=ValueData.GetAt(ValueData.FindIndex(i));
population.SetAt(population.FindIndex(i),current);
}
FitnessData.RemoveAll();
PopData.RemoveAll();
ValueData.RemoveAll();
}
# re: C++遗传算法源程序
/********************************************************************
Filename: aiWorld.h
Purpose: 遗传算法,花朵演化。
Id:
Copyright:
Licence:
*********************************************************************/
#ifndef AIWORLD_H_
#define AIWORLD_H_
#include <iostream>
#include <ctime>
#include <cstdlib>
#include <cmath>
#define kMaxFlowers 10
using std::cout;
using std::endl;
class ai_World
{
public:
ai_World()
{
srand(time(0));
}
~ai_World() {}
int temperature[kMaxFlowers]; //温度
int water[kMaxFlowers]; //水质
int sunlight[kMaxFlowers]; //阳光
int nutrient[kMaxFlowers]; //养分
int beneficialInsect[kMaxFlowers]; //益虫
int harmfulInsect[kMaxFlowers]; //害虫
int currentTemperature;
int currentWater;
int currentSunlight;
int currentNutrient;
int currentBeneficialInsect;
int currentHarmfulInsect;
/**
第一代花朵
*/
void Encode();
/**
花朵适合函数
*/
int Fitness(int flower);
/**
花朵演化
*/
void Evolve();
/**
返回区间[start, end]的随机数
*/
inline int tb_Rnd(int start, int end)
{
if (start > end)
return 0;
else
{
//srand(time(0));
return (rand() % (end + 1) + start);
}
}
/**
显示数值
*/
void show();
};
// ----------------------------------------------------------------- //
void ai_World::Encode()
// ----------------------------------------------------------------- //
{
int i;
for (i=0;i<kMaxFlowers;i++)
{
temperature[i]=tb_Rnd(1,75);
water[i]=tb_Rnd(1,75);
sunlight[i]=tb_Rnd(1,75);
nutrient[i]=tb_Rnd(1,75);
beneficialInsect[i]=tb_Rnd(1,75);
harmfulInsect[i]=tb_Rnd(1,75);
}
currentTemperature=tb_Rnd(1,75);
currentWater=tb_Rnd(1,75);
currentSunlight=tb_Rnd(1,75);
currentNutrient=tb_Rnd(1,75);
currentBeneficialInsect=tb_Rnd(1,75);
currentHarmfulInsect=tb_Rnd(1,75);
currentTemperature=tb_Rnd(1,75);
currentWater=tb_Rnd(1,75);
currentSunlight=tb_Rnd(1,75);
currentNutrient=tb_Rnd(1,75);
currentBeneficialInsect=tb_Rnd(1,75);
currentHarmfulInsect=tb_Rnd(1,75);
}
// ----------------------------------------------------------------- //
int ai_World::Fitness(int flower)
// ----------------------------------------------------------------- //
{
int theFitness;
theFitness=abs(temperature[flower]-currentTemperature);
theFitness=theFitness+abs(water[flower]-currentWater);
theFitness=theFitness+abs(sunlight[flower]-currentSunlight);
theFitness=theFitness+abs(nutrient[flower]-currentNutrient);
theFitness=theFitness+abs(beneficialInsect[flower]-currentBeneficialInsect);
theFitness=theFitness+abs(harmfulInsect[flower]-currentHarmfulInsect);
return (theFitness);
}
// ----------------------------------------------------------------- //
void ai_World::Evolve()
// ----------------------------------------------------------------- //
{
int fitTemperature[kMaxFlowers];
int fitWater[kMaxFlowers];
int fitSunlight[kMaxFlowers];
int fitNutrient[kMaxFlowers];
int fitBeneficialInsect[kMaxFlowers];
int fitHarmfulInsect[kMaxFlowers];
int fitness[kMaxFlowers];
int i;
int leastFit=0;
int leastFitIndex;
for (i=0;i<kMaxFlowers;i++)
if (Fitness(i)>leastFit)
{
leastFit=Fitness(i);
leastFitIndex=i;
}
temperature[leastFitIndex]=temperature[tb_Rnd(0,kMaxFlowers - 1)];
water[leastFitIndex]=water[tb_Rnd(0,kMaxFlowers - 1)];
sunlight[leastFitIndex]=sunlight[tb_Rnd(0,kMaxFlowers - 1)];
nutrient[leastFitIndex]=nutrient[tb_Rnd(0,kMaxFlowers - 1)];
beneficialInsect[leastFitIndex]=beneficialInsect[tb_Rnd(0,kMaxFlowers - 1)];
harmfulInsect[leastFitIndex]=harmfulInsect[tb_Rnd(0,kMaxFlowers - 1)];
for (i=0;i<kMaxFlowers;i++)
{
fitTemperature[i]=temperature[tb_Rnd(0,kMaxFlowers - 1)];
fitWater[i]=water[tb_Rnd(0,kMaxFlowers - 1)];
fitSunlight[i]=sunlight[tb_Rnd(0,kMaxFlowers - 1)];
fitNutrient[i]=nutrient[tb_Rnd(0,kMaxFlowers - 1)];
fitBeneficialInsect[i]=beneficialInsect[tb_Rnd(0,kMaxFlowers - 1)];
fitHarmfulInsect[i]=harmfulInsect[tb_Rnd(0,kMaxFlowers - 1)];
}
for (i=0;i<kMaxFlowers;i++)
{
temperature[i]=fitTemperature[i];
water[i]=fitWater[i];
sunlight[i]=fitSunlight[i];
nutrient[i]=fitNutrient[i];
beneficialInsect[i]=fitBeneficialInsect[i];
harmfulInsect[i]=fitHarmfulInsect[i];
}
for (i=0;i<kMaxFlowers;i++)
{
if (tb_Rnd(1,100)==1)
temperature[i]=tb_Rnd(1,75);
if (tb_Rnd(1,100)==1)
water[i]=tb_Rnd(1,75);
if (tb_Rnd(1,100)==1)
sunlight[i]=tb_Rnd(1,75);
if (tb_Rnd(1,100)==1)
nutrient[i]=tb_Rnd(1,75);
if (tb_Rnd(1,100)==1)
beneficialInsect[i]=tb_Rnd(1,75);
if (tb_Rnd(1,100)==1)
harmfulInsect[i]=tb_Rnd(1,75);
}
}
void ai_World::show()
{
// cout << "/t temperature water sunlight nutrient beneficialInsect harmfulInsect/n";
cout << "current/t " << currentTemperature << "/t " << currentWater << "/t ";
cout << currentSunlight << "/t " << currentNutrient << "/t ";
cout << currentBeneficialInsect << "/t " << currentHarmfulInsect << "/n";
for (int i=0;i<kMaxFlowers;i++)
{
cout << "Flower " << i << ": ";
cout << temperature[i] << "/t ";
cout << water[i] << "/t ";
cout << sunlight[i] << "/t ";
cout << nutrient[i] << "/t ";
cout << beneficialInsect[i] << "/t ";
cout << harmfulInsect[i] << "/t ";
cout << endl;
}
}
#endif // AIWORLD_H_
//test.cpp
#include <iostream>
#include "ai_World.h"
using namespace std;
int main()
{
ai_World a;
a.Encode();
// a.show();
for (int i = 0; i < 10; i++)
{
cout << "Generation " << i << endl;
a.Evolve();
a.show();
}
system("PAUSE");
return 0;
}
希望本文所述对大家的C++程序设计有所帮助。