public IPopulation EvolvePopulation(IPopulation oldPopulation)
{
var newPopulation = _populationFactory.CreatePopulation(oldPopulation.Size);
var individualIndexOffset = 0;
if (_elitism)
{
newPopulation.SetIndividual(0, oldPopulation.MostSuitableIndividualToProblem);
individualIndexOffset = 1;
}
// Populate 'newPopulation' with children from the parents in 'oldPopulation' to exploit the current knowledge.
for (var individualIndex = individualIndexOffset; individualIndex < newPopulation.Size; individualIndex++)
{
var resultingIndividualFromCrossoverOperation =
_crossoverOperator.PerformCrossover(oldPopulation);
_problemService.MakeSolutionValid(resultingIndividualFromCrossoverOperation);
newPopulation.SetIndividual(individualIndex, resultingIndividualFromCrossoverOperation);
}
// Mutate each individual in the new population to explore the problem domain.
for (var individualIndex = individualIndexOffset; individualIndex < oldPopulation.Size; individualIndex++)
{
// TODO: Refactor the 'currentIndividual.Chromosome' - shouldn't be able to view Chromosome.
var currentIndividual = newPopulation.GetIndividual(individualIndex);
_mutationOperator.PerformMutation(currentIndividual);
}
return(newPopulation);
}
public IPopulation GenerateInitialisedPopulation(int size)
{
var population = _populationFactory.CreatePopulation(size);
population.InitialisePopulation();
UpdatePopulationSuitability(population);
return(population);
}
/// <summary>
/// Finds the individual with the highest suitability from a random population sample.
/// </summary>
/// <param name="population">The population to select from</param>
/// <returns>The most suitable individual from the population sample</returns>
public IIndividual SelectIndividualFromPopulation(IPopulation population)
{
var tournamentPopulation = _populationFactory.CreatePopulation(tournamentSize);
for (var i = 0; i < tournamentPopulation.Size; i++)
{
var randomIndividualIndex = _random.Next(0, population.Size);
var randomIndividual = population.GetIndividual(randomIndividualIndex);
tournamentPopulation.SetIndividual(i, randomIndividual);
}
_environmentService.UpdatePopulationSuitability(tournamentPopulation);
return(tournamentPopulation.MostSuitableIndividualToProblem);
}
