public ReproduceAndReplace_Node(ScoredDistribution <Organism> scoredDistribution_organisms, Species new_species)
{
this.scoredDistribution_organisms = scoredDistribution_organisms;
this.new_species = new_species;
}
/// <summary>
/// Reproduces the surviving species based on their fitness scores. Chooses the organisms in the species to mate based on fitness scores as well. Replaces the previous generation
/// with the newly created organisms. Removes extinct species if necessary. Adjusts compatibility distance after replacement.
/// See <see cref="NEAT.NEATClient.Evolve"/> before using!
/// </summary>
/// <remarks>
/// Decides the amount of offspring (nk) each species (k) should be allotted via the following equation:
/// <para/>
/// nk = P * (Fk / Ft)
/// <para/>
/// Where:
/// <list type="bullet">
/// <item>k: The species.</item>
/// <item>nk: The number of new organisms for species k in the next generation.</item>
/// <item>P: The desired new population count.</item>
/// <item>Fk: The average fitness score of the species.</item>
/// <item>Ft: The sum of all fitness score averages of every species.</item>
/// </list>
/// </remarks>
public void ReproduceAndReplace()
{
double total_speciesFitness = Species.Sum(x => x.AverageFitnessScore);
Dictionary <Species, ReproduceAndReplace_Node> stored_distributionsSpecies = new Dictionary <Species, ReproduceAndReplace_Node>(Species.Count);
List <Organism> next_generation = new List <Organism>(NumOrganisms); //All of the new organisms.
HashSet <Species> next_species = new HashSet <Species>(Species.Count);
#region Reproduction
foreach (Species species in Species)
{
//Calculate the number of organisms every species will have:
int num_alloted_offspring = (int)(NumOrganisms * (species.AverageFitnessScore / total_speciesFitness));
//Prepare new species for placement:
Species creation_species = new Species();
next_species.Add(creation_species);
//Prepare ScoredDistribution for selecting organisms to mate:
ScoredDistribution <Organism> internal_organisms = new ScoredDistribution <Organism>(species.Size, Pedigree.Random);
foreach (Organism organism in species)
{
internal_organisms.Add(organism, organism.FitnessScore);
}
stored_distributionsSpecies.Add(species, new ReproduceAndReplace_Node(internal_organisms, creation_species));
//Actaully mate the organisms:
for (int i = 0; i < num_alloted_offspring; ++i)
{
Organism random_organism_1 = internal_organisms.ChooseValue();
Organism random_organism_2 = internal_organisms.ChooseValue(random_organism_1); //We don't want any self-replication...
if (random_organism_2 == null)
{
random_organism_2 = random_organism_1; //Unless that's the only option ;) Only happens when the organism is the only one in the species.
}
Organism baby = new Organism(random_organism_1.Genome.Crossover(random_organism_1.FitnessScore, random_organism_2.Genome, random_organism_2.FitnessScore,
Pedigree.Random));
next_generation.Add(baby);
creation_species.AddOrganism(baby);
}
}
while (next_generation.Count < NumOrganisms) //We need more organisms, give it to some random species. Super rare that this doesn't happen.
{
ReproduceAndReplace_Node chosen_last_node = stored_distributionsSpecies[Species.RandomValue(Pedigree.Random)];
ScoredDistribution <Organism> last_round_distribution = chosen_last_node.scoredDistribution_organisms;
Species last_round_species = chosen_last_node.new_species;
Organism random_organism_1 = last_round_distribution.ChooseValue();
Organism random_organism_2 = last_round_distribution.ChooseValue(random_organism_1); //We don't want any self-replication...
if (random_organism_2 == null)
{
random_organism_2 = random_organism_1; //Unless that's the only option ;) Only happens when the organism is the only one in the species.
}
Organism baby = new Organism(random_organism_1.Genome.Crossover(random_organism_1.FitnessScore, random_organism_2.Genome, random_organism_2.FitnessScore,
Pedigree.Random));
next_generation.Add(baby);
last_round_species.AddOrganism(baby);
}
#endregion Reproduction
#region Replacement
//Organisms:
Organisms.Clear();
Organisms.AddRange(next_generation);
//Species:
Species.Clear();
foreach (Species species in next_species)
{
Species.Add(species);
}
#endregion Replacement
RemoveExtinctions();
CompatibilityDistance += CD_function.Invoke(Species.Count);
}