void selection::sigmaScaling(vector<individual*> &adults, vector<individual*> &parents, int count){
int i,
size = adults.size();
float std = 0,
avg,
sum = 0;
vector<float> sigmaValues;
vector<individual*> p;
for(i = 0; i < size; i++){ //Calc total fitness
sum += adults[i]->getFitness();
}
avg = sum / static_cast<float>(size);
for(int i = 0; i < size; i++){ //Standard deviation
std += pow(adults[i]->getFitness()-avg, 2);
}
std = sqrt(sum/size);
sum = 0;
for(i = 0; i < size; i++){ //Calculate sigma values (unnormalized)
sigmaValues.push_back(exp((1+( adults[i]->getFitness()-avg )/(2*std))));
sum += sigmaValues[i];
}
for(i = 0; i < size; i++){ //Normalized probability
sigmaValues[i] = sigmaValues[i]/sum;
}
p = rouletteWheel(sigmaValues, adults, count);
parents.insert(parents.end(), p.begin(), p.end());
}
//Fitness Proportionate
void selection::fitnessProportionate(vector<individual*> &adults, vector<individual*> &parents, int count){
int sum = 0,
i;
vector<float> fitnessValues;
vector<individual*> p;
for(i = 0; i < adults.size(); i++){ //Sum up fitness values
fitnessValues.push_back(adults[i]->getFitness());
sum += fitnessValues[i];
}
for(i = 0; i < fitnessValues.size(); i++){ //Calculate probabilities
fitnessValues[i] = fitnessValues[i]/sum;
}
p = rouletteWheel(fitnessValues, adults, count);
parents.insert(parents.end(), p.begin(), p.end());
}
void selection::rankSelection(vector<individual*> &adults, vector<individual*> &parents, int count){
vector<float> rankValues;
int i,
size = adults.size(),
r = size;
float num = r-1,
sum = 0.0f;
vector<individual*> p;
sort(adults.begin(), adults.end(), fitnessSortFunc);
for(i = 0; i < size; i++){ //Calculate rank values
rankValues.push_back(exp((MIN_RANKSELECT_VAL+(MAX_RANKSELECT_VAL-MIN_RANKSELECT_VAL)*(((r-1)/num)))));
sum += rankValues[i];
r--;
}
for(i = 0; i < size; i++){ //Calculate normalized probabilities
rankValues[i] = rankValues[i]/sum;
}
p = rouletteWheel(rankValues, adults, count);
parents.insert(parents.end(), p.begin(), p.end());
}
//run the genetic algorithm initialized before with some training parameters:
//training location, training algorithm, desired error, max_epochs, epochs_between_reports
//see "FeedForwardNNTrainer" class for more details
//printtype specifies how much verbose will be the execution (PRINT_ALL,PRINT_MIN,PRINT_OFF)
void GAFeedForwardNN::evolve(const int n, const float * params, const int printtype){
if(n<5){printf("TOO FEW PARAMETERS FOR TRAINING\n");exit(1);}
int layers[nhidlayers+2];
int functs[nhidlayers+2];
float learningRate;
float fitnesses[popsize];
float totfitness=0;
float bestFitnessEver=0;
FloatChromosome newpop[popsize];
layers[0]=trainingSet->getNumOfInputsPerInstance();
layers[nhidlayers+1]=trainingSet->getNumOfOutputsPerInstance();
//for each generation
for(int gen=0;gen<generations;gen++){
float bestFitnessGeneration=0;
int bestFitGenIndex=0;
totfitness=0;
printf("GENERATION NUMBER:\t%d\n\n",gen);
//fitness evaluation of each individual
for(int i=0;i<popsize;i++){
printf("\nINDIVIDUAL N:\t%d\n",i);
//decode the chromosome hidden layers sizes
for(int j=0;j<nhidlayers;j++){
layers[j+1]=chromosomes[i].getElement(j);
}
//decode the chromosome activation functions for each layer
for(int j=0;j<nhidlayers+2;j++){
functs[j]=chromosomes[i].getElement(j+nhidlayers);
}
//decode the chromosome learning rate
learningRate=chromosomes[i].getElement(nhidlayers+nhidlayers+2);
float medium=0;
FeedForwardNN mseT;
//do a number of evaluations with different weights and average the results
for(int n=0;n<numberofevaluations;n++){
//choose what to print based on user's choice
int print=PRINT_ALL;
if(printtype==PRINT_MIN){
if(n==0)
print=PRINT_MIN;
else
print=PRINT_OFF;
}
if(printtype==PRINT_OFF)
print=PRINT_OFF;
//decode the chromosome into a real network
FeedForwardNN net(nhidlayers+2,layers,functs);
FeedForwardNNTrainer trainer;
trainer.selectTrainingSet(*trainingSet);
if(testSet!=NULL){
trainer.selectTestSet(*testSet);
}
trainer.selectNet(net);
trainer.selectBestMSETestNet(mseT);
float par[]={params[0],params[1],params[2],params[3],params[4],learningRate,0,SHUFFLE_ON,ERROR_LINEAR};
//do the training of the net and evaluate is MSE error
medium+=trainer.train(9,par,print)/float(numberofevaluations);
}
//the fitness is computed as the inverse of the MSE
fitnesses[i]=1.0f/medium;
printf("FITNESS:\t%.2f\n\n",fitnesses[i]);
//updates the best individual of the generation
if(fitnesses[i]>bestFitnessGeneration){bestFitnessGeneration=fitnesses[i];bestFitGenIndex=i;}
//if this is the best fitness ever it store the network in bestNet
if(bestNet!=NULL)
if(fitnesses[i]>bestFitnessEver){*bestNet=mseT;bestFitnessEver=fitnesses[i];}
totfitness+=fitnesses[i];
}
//the best individual is always carried to the next generation
newpop[0]=chromosomes[bestFitGenIndex];
//generate the new population
for(int i=1;i<popsize;i++){
//selection
int firstmate=0,secondmate=0;
//first mate
switch(selectionalgorithm){
case ROULETTE_WHEEL: firstmate=rouletteWheel(popsize,fitnesses); break;
case TOURNAMENT_SELECTION: firstmate=tournament(popsize,fitnesses,popsize/5+1); break;
default: printf("SELECTION ALGORITHM NOT IMPLEMENTED YET\n");exit(1);break;
}
//second mate
do{
switch(selectionalgorithm){
case ROULETTE_WHEEL: secondmate=rouletteWheel(popsize,fitnesses); break;
case TOURNAMENT_SELECTION: secondmate=tournament(popsize,fitnesses,popsize/5+1); break;
default: printf("SELECTION ALGORITHM NOT IMPLEMENTED YET\n");exit(1);break;
}
}while(firstmate==secondmate);
FloatChromosome child;
//do the crossover
child=crossover(chromosomes[firstmate],chromosomes[secondmate],pcross);
//and the mutation
child=mutation(child,pmut,maxdimhiddenlayers,nhidlayers);
//and put the child in the new generation
newpop[i]=child;
}
//copy the new generation over the older one, wich is the one we will still use
for(int i=0;i<popsize;i++){
chromosomes[i]=newpop[i];
}
}
}
