/// <summary>
/// Add a child to the next iteration.
/// </summary>
/// <param name="genome">The child.</param>
/// <returns>True, if the child was added successfully.</returns>
public bool AddChild(IGenome genome)
{
lock (_newPopulation)
{
if (_newPopulation.Count < Population.PopulationSize)
{
// don't readd the old best genome, it was already added
if (genome != _oldBestGenome)
{
if (ValidationMode)
{
if (_newPopulation.Contains(genome))
{
throw new EncogError(
"Genome already added to population: "
+ genome);
}
}
_newPopulation.Add(genome);
}
if (!Double.IsInfinity(genome.Score) &&
!Double.IsNaN(genome.Score) &&
BestComparer.IsBetterThan(genome,
BestGenome))
{
BestGenome = genome;
Population.BestGenome = BestGenome;
}
return(true);
}
return(false);
}
}
/// <inheritdoc />
public void Iteration()
{
if (!_initialized)
{
PreIteration();
}
if (Population.Species.Count == 0)
{
throw new EncogError("Population is empty, there are no species.");
}
IterationNumber++;
// Clear new population to just best genome.
_newPopulation.Clear();
_newPopulation.Add(BestGenome);
_oldBestGenome = BestGenome;
// execute species in parallel
IList <EAWorker> threadList = new List <EAWorker>();
foreach (ISpecies species in Population.Species)
{
int numToSpawn = species.OffspringCount;
// Add elite genomes directly
if (species.Members.Count > 5)
{
var idealEliteCount = (int)(species.Members.Count * EliteRate);
int eliteCount = Math.Min(numToSpawn, idealEliteCount);
for (int i = 0; i < eliteCount; i++)
{
IGenome eliteGenome = species.Members[i];
if (_oldBestGenome != eliteGenome)
{
numToSpawn--;
if (!AddChild(eliteGenome))
{
break;
}
}
}
}
// now add one task for each offspring that each species is allowed
while (numToSpawn-- > 0)
{
var worker = new EAWorker(this, species);
threadList.Add(worker);
}
}
// run all threads and wait for them to finish
Parallel.ForEach(threadList, currentTask => currentTask.PerformTask());
// validate, if requested
if (ValidationMode)
{
if (_oldBestGenome != null &&
!_newPopulation.Contains(_oldBestGenome))
{
throw new EncogError(
"The top genome died, this should never happen!!");
}
if (BestGenome != null &&
_oldBestGenome != null &&
BestComparer.IsBetterThan(_oldBestGenome,
BestGenome))
{
throw new EncogError(
"The best genome's score got worse, this should never happen!! Went from "
+ _oldBestGenome.Score + " to "
+ BestGenome.Score);
}
}
_speciation.PerformSpeciation(_newPopulation);
// purge invalid genomes
Population.PurgeInvalidGenomes();
}
