/// <summary>
/// This is the method that invokes the operator. This should not normally be called explicitly.
/// </summary>
/// <param name="currentPopulation"></param>
/// <param name="newPopulation"></param>
/// <param name="fitnessFunctionDelegate"></param>
public new virtual void Invoke(Population currentPopulation, ref Population newPopulation, FitnessFunction fitnessFunctionDelegate)
{
if (currentPopulation.Solutions == null || currentPopulation.Solutions.Count == 0)
{
throw new ArgumentException("There are no Solutions in the current Population.");
}
if (newPopulation == null)
{
newPopulation = currentPopulation.CreateEmptyCopy();
}
CurrentPopulation = currentPopulation;
NewPopulation = newPopulation;
FitnessFunction = fitnessFunctionDelegate;
if (!Enabled)
{
return;
}
//TODO: Investigate this bizare code!!!
//need to store this as we cannot handle a change until once this generation has started
//_replacementMethodS = ReplacementMethod;
int maxLoop = 100;
int eliteCount = 0;
//reset the number of evaluations
_evaluations = 0;
//now that we know how many children we are to be creating, in the case of 'Delete Last'
//we copy the current generation across and add new children where they are greater than
//the worst solution.
if (_replacementMethodS == ReplacementMethod.DeleteLast)
{
//copy everything accross including the elites
NewPopulation.Solutions.Clear();
NewPopulation.Solutions.AddRange(CurrentPopulation.Solutions);
}
else
{
//just copy the elites, this will take all elites
//TODO: Sort out what we do if we overfill the population with elites
var elites = CurrentPopulation.GetElites();
eliteCount = elites.Count();
if (elites != null && eliteCount > 0)
{
NewPopulation.Solutions.AddRange(elites);
}
}
_currentPopulationSize = CurrentPopulation.Solutions.Count;
_numberOfChildrenToGenerate =
_currentPopulationSize - eliteCount;
while (_numberOfChildrenToGenerate > 0)
{
//emergency exit
if (maxLoop <= 0)
{
throw new ChromosomeException("Unable to create a suitable child. If duplicates have been disallowed then consider increasing the chromosome length or increasing the number of elites.");
}
//these will hold the children
Chromosome c1 = null;
Chromosome c2 = null;
//select some parents
var parents = CurrentPopulation.SelectParents();
var p1 = parents [0];
var p2 = parents [1];
//crossover
var crossoverData = CreateCrossoverData(p1.Genes.Count, CrossoverType);
PerformCrossover(p1, p2, crossoverData, out c1, out c2);
//pass the children out to derived classes
//(e.g. CrossoverMutate class uses this to perform mutation)
if (OnCrossoverComplete != null)
{
var eventArgs = new CrossoverEventArgs(crossoverData, p1, p2, c1, c2);
OnCrossoverComplete(this, eventArgs);
}
if (AddChild(c1))
{
_numberOfChildrenToGenerate--;
}
else
{
//unable to create child
maxLoop--;
}
//see if we can add the secomd
if (_numberOfChildrenToGenerate > 0)
{
if (AddChild(c2))
{
_numberOfChildrenToGenerate--;
}
else
{
//unable to create child
maxLoop--;
}
}
}
//TODO: Test this, we shouldn't need it.
newPopulation = NewPopulation;
}
/// <summary>
/// Main process loop for performing a crossover on a population.
/// </summary>
protected void Process()
{
int maxLoop = 100;
int eliteCount = 0;
//reset the number of evaluations
_evaluations = 0;
//now that we know how many children we are to be creating, in the case of 'Delete Last'
//we copy the current generation across and add new children where they are greater than
//the worst solution.
if (_replacementMethodS == ReplacementMethod.DeleteLast)
{
//copy everything accross including the elites
_newPopulation.Solutions.Clear();
_newPopulation.Solutions.AddRange(_currentPopulation.Solutions);
}
else
{
//just copy the elites, this will take all elites
//TODO: Sort out what we do if we overfill the population with elites
var elites = _currentPopulation.GetElites();
eliteCount = elites.Count();
if (elites != null && eliteCount > 0)
{
_newPopulation.Solutions.AddRange(elites);
}
}
_currentPopulationSize = _currentPopulation.Solutions.Count;
_numberOfChildrenToGenerate =
_currentPopulationSize - eliteCount;
while (_numberOfChildrenToGenerate > 0)
{
//emergency exit
if (maxLoop <= 0)
{
throw new ChromosomeException("Unable to create a suitable child. If duplicates have been disallowed then consider increasing the chromosome length or increasing the number of elites.");
}
//these will hold the children
Chromosome c1 = null;
Chromosome c2 = null;
//select some parents
var parents = _currentPopulation.SelectParents();
var p1 = parents [0];
var p2 = parents [1];
//crossover
var crossoverData = CreateCrossoverData(p1.Genes.Count, CrossoverType);
var crossoverResult = PerformCrossover(p1, p2, CrossoverProbability, CrossoverType, crossoverData, out c1, out c2);
//pass the children out to derived classes
//(e.g. CrossoverMutate class uses this to perform mutation)
if (OnCrossoverComplete != null)
{
var eventArgs = new CrossoverEventArgs(crossoverResult, p1, p2, c1, c2);
OnCrossoverComplete(this, eventArgs);
}
if (AddChild(c1))
{
_numberOfChildrenToGenerate--;
}
else
{
//unable to create child
maxLoop--;
}
//see if we can add the secomd
if (_numberOfChildrenToGenerate > 0)
{
if (AddChild(c2))
{
_numberOfChildrenToGenerate--;
}
else
{
//unable to create child
maxLoop--;
}
}
}
}