/// <summary>
/// Creates an initial population
/// </summary>
private void InitializePopulation()
{
ICollection <IGenotype> population;
if (AllowDuplicates)
{
population = new List <IGenotype>(PopulationSize);
}
else
{
population = new SafeHashSet <IGenotype>(MaxRetriesForDuplicates);
}
while (population.Count < PopulationSize)
{
population.Add(GenerateRandomMember());
}
Population = population.OrderByDescending(x => x.Fitness).ToList();
BestInitial = Population.First();
CreateMethod = GenotypeFactory.GetCreateMethod <Gene>(BestInitial.GetType());
}
/// <summary>
/// Runs the genetic algorithm for the specified number of generations
/// </summary>
/// <param name="numGenerations">The number of generations</param>
/// <returns></returns>
public void Run()
{
ICollection <IGenotype> nextPopulation;
List <IGenotype> parents;
Gene[][] children;
IGenotype child;
double fitness;
bool mutated, solutionFound;
ParameterCheck();
if (Population == null)
{
InitializePopulation();
}
if (AllowDuplicates)
{
nextPopulation = new List <IGenotype>(PopulationSize);
}
else
{
nextPopulation = new SafeHashSet <IGenotype>(MaxRetriesForDuplicates);
}
solutionFound = false;
if (PreserveElitePercent > 0)
{
foreach (IGenotype individual in Population.Take((int)(PreserveElitePercent * PopulationSize)).ToList())
{
nextPopulation.Add(individual);
}
}
SelectionMethod.Initialize(Population);
while (nextPopulation.Count < PopulationSize)
{
try
{
parents = SelectionMethod.DoSelection();
}
catch (SafeHashSetException)
{
Converged = true;
break;
}
// Perform crossover
children = CrossoverMethod.DoCrossover <Gene>(parents);
// Iterate through each child produced by crossover
for (int i = 0; i < children.Length; i++)
{
// Calculate fitness of child
fitness = FitnessFunction(children[i], out solutionFound);
// Perform mutation (but skip if solution has been found)
mutated = solutionFound ? false : MutationMethod.DoMutation <Gene>(ref children[i]); // TODO return mutation and use only if better fitness??? Make a parameter to turn on/off
// Recalculate fitness if mutation occurred
if (mutated)
{
fitness = FitnessFunction(children[i], out solutionFound);
}
// Instantiate child
child = CreateMethod(children[i], fitness);
try
{
nextPopulation.Add(child);
if (solutionFound)
{
break;
}
}
catch (SafeHashSetException)
{
Converged = true;
break;
}
}
if (solutionFound || Converged)
{
break;
}
}
GenerationNumber++;
SolutionFound = solutionFound;
Population = nextPopulation.OrderByDescending(x => x.Fitness).ToList();
BestCurrent = Population.First();
FinishedGeneration?.Invoke();
foreach (Termination.TerminationMethod t in TerminationMethods)
{
if (t.CheckTermination(this))
{
Terminated = true;
TerminationReached?.Invoke();
}
}
}