private DNA[] CreateDNAs(int populationSize, int generation)
{
if (generation == 1)
{
return(new DNA[populationSize]
.Select(t => new DNA((uint)CreatureCreator.NumGenesRequired))
.ToArray());
}
var numFromHallOfFame = Mathf.RoundToInt(populationSize * FractionFromHallOfFame);
// 1) select DNAs to breed new population from
var parentDNAs = new DNA[populationSize];
// 1a) add some DNA from Hall of Fame
int i;
for (i = 0; i < HallOfFame.Count && i < numFromHallOfFame; i++)
{
parentDNAs[i] = HallOfFame.Values[i];
}
// 1b) add some DNA from previous generation, based on fitness
for (; i < populationSize; ++i)
{
parentDNAs[i] =
PreviousGenerationDnasByFitness.GetRandomDistributedByKey(
new DNA((uint)CreatureCreator.NumGenesRequired)).Item2;
}
FileLogger.Log(" parentDNAs: [{0}]", parentDNAs
.Select(t => t.ToString())
.Aggregate((s, t) => string.Format("{0}, {1}", s, t)));
// 2) breed new population
var dnas = new DNA[populationSize];
// 2a) add some of the best DNA from the hall of fame directly
for (i = 0; i < numFromHallOfFame; ++i)
{
dnas[i] = HallOfFame.Values[i];
}
// 2b) breed the rest of the DNA from the prev. selected parent DNAs
for (; i < populationSize; i += 2)
{
var parents = parentDNAs.GetRandom(2);
var tuple = DNA.Breed(parents[0], parents[1]);
dnas[i] = tuple.Item1;
if (i + 1 < populationSize)
{
dnas[i + 1] = tuple.Item2;
}
}
// 3) mutate new creatures
dnas.ForEach(dna => {
dna.Mutate(MutationMax);
});
FileLogger.Log(" population: [{0}]", dnas
.Select(t => t.ToString())
.Aggregate((s, t) => string.Format("{0}, {1}", s, t)));
return(dnas);
}