population.cpp

基本遗传算法在求一个函数表达式的最大值应用！

#include "stdafx.h"
#include "population.h"
#include "chromosome.h"
#include "myRandom.h"

extern MyRandom myRandom;

Population::Population(int popsize) {
	this->PopSize = popsize;
	this->AvgFit = 0 ;
	this->Best =0;
	this->MaxFit =0;
	this->MinFit =0;
	chromosomes = new Chromosome[PopSize ];
	MatingPool = new int [PopSize ];
}

Population::Population(Population &pop) {
	this->AvgFit =pop.get_avgfit ();
	this->Best =pop.get_best ();
	this->MaxFit = pop.get_maxfit ();
	this->MinFit = pop.get_minfit ();

	chromosomes = new Chromosome[PopSize ];
	MatingPool = new int [PopSize ];
	for(int i=0;i< PopSize;i++)
	{
		chromosomes[i].copyGene(pop.chromosomes [i].myGenes ,PopSize,0);
		MatingPool[i] = pop.MatingPool[i];
	}
}

Population::~Population (){
	delete [] chromosomes;
	delete [] MatingPool;
}

void Population::evaluate() {
	for(int i=0;i<PopSize;i++)
		chromosomes[i].evaluate ();
	int    index_best = 0 ;
	double fit_sum = 0.0 ;
	double max_fit = chromosomes[0].get_fitness () ;
	double min_fit = chromosomes[0].get_fitness () ;
	for(int i=0;i<PopSize;i++)
	{
		fit_sum = fit_sum + chromosomes[i].get_fitness();
		if(max_fit<chromosomes[i].get_fitness()){
			index_best = i ;
			max_fit=chromosomes[i].get_fitness ();
		}
		if(min_fit>chromosomes[i].get_fitness ())
			min_fit = chromosomes[i].get_fitness ();
	}

	this->Best = index_best ;
	this->MaxFit = max_fit;
	this->MinFit = min_fit;
	this->AvgFit = fit_sum/(double)PopSize;
}

//赌轮选择
void Population::selection() {
	double fit_sum = 0.0;
	double mid_fit_sum = 0.0;
	double rand_data = 0.0 ;
	int j;
	for(int i=0;i<PopSize;i++)
		fit_sum = fit_sum + chromosomes[i].get_fitness();
	for(int i=0;i<PopSize;i++)
	{
		rand_data = myRandom.ddouble_random(fit_sum);
		mid_fit_sum = 0.0;
		for(j=0;j<PopSize;j++)
		{
			mid_fit_sum = mid_fit_sum + chromosomes[j].get_fitness ();
			if( mid_fit_sum >= rand_data )
				break;
		}
		MatingPool[i] = j;
	}
}

//锦标赛选择
#define theCollect 7 
void Population::tournamentSeclection (){
	////int theCollect = 7 ;           //随机选取 theCollect 个个体
	int collection[theCollect];   //存储选择的个个体的编号
	int count = 0;
	double mid_fit =0.0;

	for(int i=0;i<theCollect;i++)
		collection[i] = 0 ;

	for(int i =0;i<PopSize; i++)
	{
		for(int j =0;j< theCollect ;j++)
			collection[j] = myRandom.lim_int_random (0,PopSize);

		count = collection[0];
	    mid_fit =chromosomes[collection[0]].get_fitness();

		for(int j = 0;j< theCollect;j++)
		{
			if(mid_fit < chromosomes[collection[j]].get_fitness ())
			{
				mid_fit = chromosomes[collection[j]].get_fitness () ;
				count = collection[j];
			}  
		}
		MatingPool[i] = count ;
	}
}