/// <summary>
/// Linear crossover executor.
/// </summary>
/// <param name="population">Input population.</param>
/// <param name="xover">Crossover operator.</param>
/// <param name="xoverProbability">Crossver probability</param>
/// <param name="parents">Parents list</param>
/// <returns>Childten(individuals)</returns>
public virtual IList <IIndividual> Cross(IPopulation population, IXover xover, float xoverProbability, IList <IIndividual> parents)
{
var size = population.Size;
var offspring = new List <IIndividual>(size);
for (int i = 0; i < size; i += xover.ChildrenNumber)
{
// selected parents from population
var selectedParents = parents.Skip(i).Take(xover.ParentsNumber).ToList();
// If match the probability cross is made, otherwise the offspring is an exact copy of the parents.
// Checks if the number of selected parents is equal which the crossover expect, because the in the end of the list we can
// have some rest individual
if (selectedParents.Count == xover.ParentsNumber && RandomizationRnd.GetDouble() <= xoverProbability)
{
offspring.AddRange(xover.Cross(selectedParents));
}
else
{
offspring.AddRange(selectedParents);
}
}
return(offspring);
}
/// <summary>
/// Mutate the specified individual in population.
/// </summary>
/// <param name="individual">The individual to be mutated.</param>
/// <param name="mut_probability">The mutation probability to mutate each individual.</param>
public override void Mutate(IIndividual individual, float mutation_probabilty)
{
if (RandomizationRnd.GetDouble() <= mutation_probabilty)
{
var indexes = RandomizationRnd.GetUniqueInts(2, 0, individual.Length);
SwapGenes(indexes[0], indexes[1], individual);
}
}
/// <summary>
/// Mutate the specified individual.
/// </summary>
/// <param name="individual">The individual to be mutated.</param>
/// <param name="mutation_probabilty">The mutation probability to mutate each individual.</param>
public override void Mutate(IIndividual individual, float mutation_probabilty)
{
for (int index = 0; index < individual.Length; index++)
{
if (RandomizationRnd.GetDouble() <= mutation_probabilty)
{
individual.ReplaceGene(index, individual.GenerateGene());
}
}
}
/// <summary>
/// Cross the specified parents generating the children (Uniform cross).
/// </summary>
/// <param name="firstParent"> First parent</param>
/// <param name="secondParent">Second parent</param>
/// <returns>The offspring (children) of the parents.</returns>
private IList <IIndividual> PerfomCross(IIndividual firstParent, IIndividual secondParent)
{
var firstChild = firstParent.CreateNew();
var secondChild = firstParent.CreateNew();
// uniform cross by pmixProb
for (int i = 0; i < firstParent.Length; i++)
{
if (RandomizationRnd.GetDouble() < mixProbability)
{
firstChild.ReplaceGene(i, firstParent.GetGene(i));
secondChild.ReplaceGene(i, secondParent.GetGene(i));
}
else
{
firstChild.ReplaceGene(i, secondParent.GetGene(i));
secondChild.ReplaceGene(i, firstParent.GetGene(i));
}
}
return(new List <IIndividual> {
firstChild, secondChild
});
}
