public IIndividual PerformMutation(IIndividual individual)
{
var randomMutationLimit = _random.Next(_maxNumberOfMutations);
for (var numberOfMutations = 0; numberOfMutations < randomMutationLimit; numberOfMutations++)
{
// TODO: Implement infinity searching with boundary constraints
// Find two indices at random.
var swapIndex1 = _random.Next(individual.Chromosome.Size);
var swapIndex2 = _random.Next(individual.Chromosome.Size);
// Ensure indices are unique.
while (swapIndex1 == swapIndex2)
{
swapIndex2 = _random.Next(individual.Chromosome.Size);
}
// Store the original values.
var swapIndex1Value = individual.GetGeneValue(swapIndex1);
var swapIndex2Value = individual.GetGeneValue(swapIndex2);
// Swap the index's values.
individual.SetGeneValue(swapIndex1, swapIndex2Value);
individual.SetGeneValue(swapIndex2, swapIndex1Value);
}
return(individual);
}
public void UpdateIndividualSuitability(IIndividual individual)
{
var fitness = 0;
var multiplier = 0;
for (var i = 0; i < individual.GeneLength; i++)
{
var studentIndex = individual.GetGeneValue(i) - 1;
if (studentIndex != -1)
{
var timeslotIndex = i;
var score = GetIndividualScore(studentIndex, timeslotIndex);
if (score == 10)
{
multiplier += 2;
}
else if (score == 1)
{
multiplier += 1;
}
fitness += score;
}
}
individual.SuitabilityScore = fitness + 1 * multiplier;
}
/// <summary>
/// Perform a random splice of the genes from 'parent1' and 'parent2' to produce a child.
/// </summary>
/// <param name="parent1">The parent to take the first selection of genes from</param>
/// <param name="parent2">The parent to take the second selection of genes from</param>
/// <returns></returns>
public IIndividual PerformCrossover(IIndividual parent1, IIndividual parent2)
{
var child = _individualFactory.CreateIndividual();
// Select a random index for the crossover point.
// TODO: Make this dynamic
var minimumCrossoverLength = 1;
var crossoverIndex = _random.Next(0, child.GeneLength - minimumCrossoverLength);
for (var geneIndex = 0; geneIndex < child.GeneLength; geneIndex++)
{
int alleleFromParent;
// Take genes from 'parent1' if the crossover point hasn't been reached
if (geneIndex < crossoverIndex)
{
alleleFromParent = parent1.GetGeneValue(geneIndex);
}
// Take genes from 'parent2' if the crossover point has been reached
else
{
alleleFromParent = parent2.GetGeneValue(geneIndex);
}
child.SetGeneValue(geneIndex, alleleFromParent);
}
return(child);
}
