/// <summary>
/// Only send the random if the compoment calling shuffle doesn't need to be thread safe.
/// </summary>
public static T[] Shuffle <T>(this ICollection <T> collection, Random random = null)
{
var array = collection.ToArray();
int n = array.Length;
while (n > 1)
{
n--;
int k = random != null?random.Next(n + 1) : ProbabilityUtils.GetRandomInt(n + 1);
T value = array[k];
array[k] = array[n];
array[n] = value;
}
return(array);
}
public IChromosome[] GenerateChildren(Population population, int number, int generation, IEnvironment environment)
{
if (number < 1)
{
throw new InternalSearchException("Code 1003 (requested 0 children)");
}
selectionStrategy.SetPopulation(population, number * 2);
var mutationProbability = mutationManager.MutationProbability(population, environment, generation);
CheckMuationProbability(mutationProbability);
var children = new ConcurrentBag <IChromosome>();
var tasks = new Task[number];
for (int i = 0; i < number; i++)
{
tasks[i] = Task.Run(() =>
{
var parent1 = AssertNotNull(selectionStrategy.SelectChromosome());
var parent2 = AssertNotNull(selectionStrategy.SelectChromosome());
var child = crossoverManager.Crossover(parent1, parent2);
if (ProbabilityUtils.P(mutationProbability))
{
child.Mutate();
}
children.Add(child);
});
}
foreach (var task in tasks)
{
task.Wait();
}
return(children.ToArray());
}
