void
Strategies::Select( Population &pop, float roulette[], int size, float max ) {
/* Spin wheel untill we have enough children */
/* Make sure an individual does not mate with itself */
float spin1=0, spin2=0;
int chosen1=0, chosen2=0;
float crossover_rate = pop.GetCrossoverRate();
while (pop.GetChildren().size() < pop.GetChildrenSize()) {
/* Crossover */
if( rand()/RAND_MAX <= crossover_rate ) {
while (chosen1 == chosen2) {
spin1 = (rand() * max) / RAND_MAX;
spin2 = (rand() * max) / RAND_MAX;
for ( unsigned int i = 0; i < pop.GetAdults().size(); i++) {
if(roulette[i]<spin1) chosen1 = i;
if(roulette[i]<spin2) chosen2 = i;
}
}
pop.GetChildren().push_back(pop.GetAdults().at(chosen1).Reproduce(pop.GetAdults().at(chosen2)));
pop.GetChildren().push_back(pop.GetAdults().at(chosen2).Reproduce(pop.GetAdults().at(chosen1)));
}
/* Clone */
else {
spin1 = (rand() * max) / RAND_MAX;
for ( unsigned int i = 0; i < pop.GetAdults().size(); i++) {
if(roulette[i]<spin1) {
chosen1 = i;
}
else {
break;
}
}
pop.GetChildren().push_back(pop.GetAdults().at(chosen2));
}
chosen1 = chosen2;
}
}
void
Strategies::TournamentSelection( Population &pop ) {
/* Take care of elitism first */
Elitism( pop );
float crossover_rate = pop.GetCrossoverRate();
std::vector<Individual> group_a;
std::vector<Individual> group_b;
while ( pop.GetChildren().size() < pop.GetChildrenSize() ) {
unsigned int selector;
/* Reproduce or clone best individual */
if( rand()/RAND_MAX <= crossover_rate ) {
/* select individuals for group a */
for (unsigned int i = 0; i<pop.GetTournamentSize(); i++) {
while( group_a.size() < pop.GetTournamentSize() ) {
selector = rand() % pop.GetAdults().size();
group_a.push_back( pop.GetAdults().at( selector ) );
pop.GetAdults().erase( pop.GetAdults().begin() + selector );
}
}
float temp_fit=0;
/* Find best individual in group a */
unsigned int best_in_a=0;
for ( unsigned int i = 0; i < group_a.size(); i++ ) {
if ( temp_fit < group_a.at(i).GetFitness() ) {
best_in_a = i;
temp_fit = group_a.at(i).GetFitness();
}
}
/* select individuals for group b */
unsigned int selector;
for (unsigned int i = 0; i<pop.GetTournamentSize(); i++) {
while( group_b.size() < pop.GetTournamentSize() ) {
selector = rand() % pop.GetAdults().size();
group_b.push_back( pop.GetAdults().at( selector ) );
pop.GetAdults().erase( pop.GetAdults().begin() + selector );
}
}
/* Find best individual in group b */
unsigned int best_in_b=0;
for ( unsigned int i = 0; i < group_b.size(); i++ ) {
if ( temp_fit < group_b.at(i).GetFitness() ) {
best_in_b = i;
temp_fit = group_b.at(i).GetFitness();
}
}
pop.GetChildren().push_back( group_a.at( best_in_a ).Reproduce( group_b.at( best_in_b ) ) );
pop.GetChildren().push_back( group_b.at( best_in_b ).Reproduce( group_a.at( best_in_a ) ) );
}
else{
/* select individuals for group 1 */
for (unsigned int i = 0; i<pop.GetTournamentSize(); i++) {
while( group_a.size() < pop.GetTournamentSize() ) {
selector = rand() % pop.GetAdults().size();
group_a.push_back( pop.GetAdults().at( selector ) );
pop.GetAdults().erase( pop.GetAdults().begin() + selector );
}
}
/* Find best individual */
unsigned int best_in_a=0;
float temp_fit=0;
for ( unsigned int i = 0; i < group_a.size(); i++ ) {
if ( temp_fit < group_a.at(i).GetFitness() ) {
best_in_a = i;
temp_fit = group_a.at(i).GetFitness();
}
}
pop.GetChildren().push_back( group_a.at( best_in_a ) );
}
for ( unsigned int i = 0; i<group_a.size(); i++)
pop.GetAdults().push_back(group_a.at(i));
group_a.clear();
for ( unsigned int i = 0; i<group_b.size(); i++)
pop.GetAdults().push_back(group_b.at(i));
group_b.clear();
}
}