private static IEnumerable <double> ComputeSetValues(IEnumerable <TChromosome> chromosomes, FitnessFunction <TChromosome, TGene> fitness)
{
var setValues = chromosomes.Select(fitness.ValueFor);
if (setValues.Any(v => v <= 0))
{
return(TranslateSetValues(setValues));
}
return(setValues);
}
public override Population <TChromosome, TGene> Select(Population <TChromosome, TGene> population, FitnessFunction <TChromosome, TGene> fitness)
{
var selectedPopulation = new List <TChromosome>();
var setValues = ComputeSetValues(population.Chromosomes, fitness);
var wheelValues = ComputeWheelValues(setValues).ToList();
for (var i = 0; i < population.Size; i++)
{
var random = new Random().NextDouble();
var selectedIndex = wheelValues.FindIndex(wv => wv > random);
if (selectedIndex == wheelValues.Count - 1)
{
selectedIndex--;
}
var selectedSet = population.Chromosomes.ElementAt(selectedIndex);
selectedPopulation.Add(selectedSet);
}
return(Population <TChromosome, TGene> .Create(selectedPopulation));
}
public Population <TChromosome, TGene> Select(PopulationSelectionStrategy <TChromosome, TGene> selectionStrategy, FitnessFunction <TChromosome, TGene> fitness)
{
return(selectionStrategy.Select(this, fitness));
}