private void CalculateTotalFitness()
{
Genomes.ForEach(g =>
{
g.RebuildModelFollowingGenes();
g.UpdateFitnessScore();
});
TotalFitnessScore = Genomes.Max(g => g.Fitness);
}
/// <summary>
/// If the minimum fitness is less than 0, the absolute value of
/// it is added to every genome, so that they all have positive fitness.
/// It may be useful in some computations and it doesn't affect anything.
/// </summary>
private void MakeGenomesHaveOnlyPositiveFitnesses()
{
var minFitness = Genomes.Min(x => x.Fitness);
if (minFitness > 0)
{
return;
}
var absMinFitness = Mathf.Abs(minFitness);
Genomes.ForEach(x => x.Fitness += absMinFitness);
}
public void Evaluate(Func <IGenome, double> getFitness)
{
// Genome Fitness
Genomes.ForEach(g => g.Fitness = getFitness(g));
// Species Fitness
Species.ForEach(s => s.SetFitness());
// Population Fitness
Fitness = Genomes.Sum(g => g.Fitness);
AverageFitness = Genomes.Average(g => g.Fitness);
AverageFitness = AverageFitness == 0 ? 1 : AverageFitness;
// Genome Expected Offspring
Genomes.ForEach(g => g.ExpectedOffspring = g.Fitness / AverageFitness);
// Species Expected Offspring
Species.ForEach(s => s.SetExpectedOffspring());
}
public void SetFitness()
{
int ageDebt = (Age - LastImprovementAge + 1) - SpeciesParameters.DropOffAge;
ageDebt = ageDebt == 0 ? 1 : ageDebt;
Genomes.ForEach(g =>
{
if (ageDebt >= 1)
{
g.Fitness *= SpeciesParameters.DropOffAgePenaltyFactor;
}
if (Age <= 10)
{
g.Fitness *= SpeciesParameters.AgeSignificance;
}
if (g.Fitness < 0)
{
g.Fitness = 0.0001;
}
g.Fitness /= Genomes.Count;
});
Fitness = Genomes.Any() ? Genomes.Average(g => g.Fitness) : 0;
if (Fitness > MaxFitness)
{
MaxFitness = Fitness;
LastImprovementAge = 0;
}
else
{
LastImprovementAge++;
}
}
