protected override IList <IChromosome> PerformCross(IList <IChromosome> parents)
{
ExpressionChromosome parent1 = parents[0] as ExpressionChromosome;
ExpressionChromosome parent2 = parents[1] as ExpressionChromosome;
int index1 = (int)Math.Floor(RandomizationProvider.Current.GetDouble() * parent1.Length);
int index2 = (int)Math.Floor(RandomizationProvider.Current.GetDouble() * parent2.Length);
Gene[] subtree1 = GetSubtree(parent1.GetGenes(), index1);
Gene[] subtree2 = GetSubtree(parent2.GetGenes(), index2);
// Copy subtree2 to parent1 at index1.
ExpressionChromosome child1 = parent1.CreateNew() as ExpressionChromosome;
Gene[] result = GetNewGenes(parent1.GetGenes(), index1, subtree1, subtree2);
child1.SetGenes(result);
// Copy subtree1 to parent2 at index2.
ExpressionChromosome child2 = parent2.CreateNew() as ExpressionChromosome;
result = GetNewGenes(parent2.GetGenes(), index2, subtree2, subtree1);
child2.SetGenes(result);
List <IChromosome> childs = new List <IChromosome>();
if (child1.Length < maxLength)
{
childs.Add(child1);
}
if (child2.Length < maxLength)
{
childs.Add(child2);
}
return(childs);
}
