private CodeTree <S, G, R> Combine(GenePool <S, G, R> genePool, CodeTree <S, G, R> source,
CodeTree <S, G, R> remove, CodeTree <S, G, R> replace)
{
var copy = source;
if (source == remove)
{
return(replace.Clone());
}
if (copy.Node.Kind != NodeKind.Terminal)
{
for (int i = 0; i <= copy.Children.GetUpperBound(0); i++)
{
var child = Combine(genePool, copy.Children[i], remove, replace);
copy.Children[i] = child;
if (genePool.GetCanMutate())
{
copy.Children[i].Node = genePool.GetTerminal();
}
}
}
return(copy);
}
public CodeTree(GenePool <S, G, R> genePool, Node node, int maxDepth)
{
Node = node;
if (Node.Kind != NodeKind.Terminal)
{
Children = Enumerable.Range(1, Node.ChildCount).Select(
x => new CodeTree <S, G, R>(genePool, GetNode(genePool, maxDepth), maxDepth - 1)).ToArray();
}
}
private Node GetNode(GenePool <S, G, R> genePool, int maxDepth)
{
if (maxDepth > 0)
{
return(genePool.GetFunctionOrTerminal());
}
else
{
return(genePool.GetTerminal());
}
}
private void Crossover(GenePool <S, G, R> genePool,
CodeTree <S, G, R> parent1, CodeTree <S, G, R> parent2,
out CodeTree <S, G, R> child1, out CodeTree <S, G, R> child2)
{
var nodes1 = parent1.ToList();
var nodes2 = parent2.ToList();
int crossover1 = genePool.Next(0, nodes1.Count - 1);
int crossover2 = genePool.Next(0, nodes2.Count - 1);
child1 = Combine(genePool, parent1, nodes1[crossover1], nodes2[crossover2]);
child2 = Combine(genePool, parent2, nodes2[crossover2], nodes1[crossover1]);
}
public static void Evolve(S settings, CancellationTokenSource cts,
Action <EntitySet <S, G, R> > onResultSet,
Action <AggregateException> onErrors, Action onSuccess)
{
try
{
Contract.Requires(settings != null, nameof(settings));
settings.Validate();
var genePool = new GenePool <S, G, R>(settings);
EntitySet <S, G, R> entitySet = null;
for (var cohortId = 0; cohortId < settings.MaxCohorts; cohortId++)
{
entitySet = new EntitySet <S, G, R>(
settings, genePool, cohortId, entitySet);
var metGoals = entitySet.CompileAndRun(settings, cts);
onResultSet(entitySet);
if (metGoals)
{
break;
}
}
onSuccess();
}
catch (AggregateException errors)
{
onErrors(errors);
}
catch (Exception error)
{
onErrors(new AggregateException(error));
}
}
internal EntitySet(S settings, GenePool <S, G, R> genePool, int cohortId,
IEnumerable <Entity <S, G, R> > entities)
{
Cohort = new Cohort(cohortId);
if (entities == null)
{
for (int entityId = 0; entityId <= settings.Population - 1; entityId++)
{
var codeTree = new CodeTree <S, G, R>(
genePool, genePool.GetFunction(), settings.MaxTreeDepth);
var knownAs = new KnownAs(Cohort, entityId);
Items.Add(new Entity <S, G, R>(knownAs, codeTree));
}
}
else
{
Items.AddRange(entities.Take(settings.NumToKeep));
for (int entityId = Count; entityId <= settings.Population - 2; entityId += 2)
{
CodeTree <S, G, R> child1, child2, parent1, parent2;
int index1, index2;
SelectAndCloneParents(genePool, this, settings.NumToKeep,
out index1, out parent1, out index2, out parent2);
Crossover(genePool, parent1, parent2, out child1, out child2);
Items.Add(new Entity <S, G, R>(new KnownAs(Cohort, entityId),
this[index1].KnownAs, this[index2].KnownAs, child1));
Items.Add(new Entity <S, G, R>(new KnownAs(Cohort, entityId + 1),
this[index1].KnownAs, this[index2].KnownAs, child2));
}
}
}
private void SelectAndCloneParents(GenePool <S, G, R> genePool,
EntitySet <S, G, R> entitySet, int limit,
out int index1, out CodeTree <S, G, R> parent1,
out int index2, out CodeTree <S, G, R> parent2)
{
var totalFitness = 0.0;
for (int i = 0; i < limit; i++)
{
totalFitness += entitySet[i].Report.Fitness;
}
index1 = -1;
index2 = -1;
while ((index1 == -1) | (index2 == -1))
{
for (int i = 0; i < limit; i++)
{
var range = entitySet[i].Report.Fitness / totalFitness;
if (genePool.InRange(range))
{
if (index1 == -1)
{
index1 = i;
}
else
{
index2 = i;
}
}
}
}
parent1 = entitySet[index1].CodeTree.DeepClone();
parent2 = entitySet[index2].CodeTree.DeepClone();
}