/// <summary>
/// Evaluates a list of genomes. Here we select the genomes to be evaluated before invoking
/// _innerEvaluator to evaluate them.
/// </summary>
public void Evaluate(IList <TGenome> genomeList, string userName)
{
// Select the genomes to be evaluated. Place them in a temporary list of genomes to be
// evaluated after the genome selection loop. The selection is not performed in series
// so that we can wrap parallel execution versions of IGenomeListEvaluator.
List <TGenome> filteredList = new List <TGenome>(genomeList.Count);
foreach (TGenome genome in genomeList)
{
if (_selectionPredicate.Invoke(genome))
{ // Add the genome to the temp list for evaluation later.
filteredList.Add(genome);
}
else
{ // Register that the genome skipped an evaluation.
genome.EvaluationInfo.EvaluationPassCount++;
}
}
// Evaluate selected genomes.
_innerEvaluator.Evaluate(filteredList, userName);
}
/// <summary>
/// Main genome evaluation loop with no phenome caching (decode on each evaluation).
/// Individuals are competed pairwise against every champion in the hall of fame.
/// The final fitness score is the weighted sum of the fitness versus the champions
/// and the fitness score by the inner evaluator.
/// </summary>
public void Evaluate(IList <TGenome> genomeList)
{
_innerEvaluator.Evaluate(genomeList);
//Create a temporary list of fitness values with the scores of the inner evaluator.
FitnessInfo[] results = new FitnessInfo[genomeList.Count];
for (int i = 0; i < results.Length; i++)
{
results[i] = new FitnessInfo(genomeList[i].EvaluationInfo.Fitness * (1.0 - _hallOfFameWeight),
genomeList[i].EvaluationInfo.AlternativeFitness * (1.0 - _hallOfFameWeight));
}
// Calculate how much each champion game is worth
double championGameWeight = _hallOfFameWeight / (double)_hallOfFame.Count;
// Exhaustively compete individuals against each other.
Parallel.For(0, genomeList.Count, delegate(int i)
{
// Decode the first genome.
TPhenome phenome1 = _genomeDecoder.Decode(genomeList[i]);
// Check that the first genome is valid.
if (phenome1 == null)
{
return;
}
for (int j = 0; j < _hallOfFame.Count; j++)
{
// Decode the second genome.
TPhenome phenome2 = _genomeDecoder.Decode(_hallOfFame[j]);
// Check that the second genome is valid.
if (phenome2 == null)
{
continue;
}
// Compete the two individuals against each other and get the results.
FitnessInfo fitness1, fitness2;
_phenomeEvaluator.Evaluate(phenome1, phenome2, out fitness1, out fitness2);
// Add the results to each genome's overall fitness.
// Note that we need to use a lock here because
// the += operation is not atomic.
// ENHANCEMENT: I don't think this lock is necessary here since the hall of fame
// is our inner loop.
lock (results)
{
results[i]._fitness += fitness1._fitness * championGameWeight;
results[i]._alternativeFitness += fitness1._alternativeFitness * championGameWeight;
}
}
});
// Update every genome in the population with its new fitness score.
for (int i = 0; i < results.Length; i++)
{
genomeList[i].EvaluationInfo.SetFitness(results[i]._fitness);
genomeList[i].EvaluationInfo.AlternativeFitness = results[i]._alternativeFitness;
}
}
