}//End of Selection()
internal KNPSpecimen Tournament(KNPSpecimen[] population, int tournamentSize)
{
Random random = new Random();
KNPSpecimen fittest = new KNPSpecimen();
double fittestScore = Double.MinValue;
KNPSpecimen[] contestants = new KNPSpecimen[tournamentSize];
int randomContestant = random.Next(populationSize);
for (int i = 0; i < tournamentSize; i++)
{
while (Array.Find(contestants, c => object.ReferenceEquals(c, population[randomContestant])) != null)
{
randomContestant = random.Next(populationSize);
}
contestants[i] = population[randomContestant];
}
double contestantScore;
foreach (KNPSpecimen contestant in contestants)
{
contestantScore = contestant.Evaluate(problem);
if (contestantScore > fittestScore)
{
fittestScore = contestantScore;
fittest = new KNPSpecimen((sbyte[])contestant.Genotype.Clone(), testdata);
}
}
return(fittest);
}//End of Tournament
internal KNPSpecimen[] Initialize()
{
//create initial genotypes
Random rnd = new Random();
sbyte[] initialGenotype = new sbyte[testdata.ItemCount * testdata.KnapsackCount];
for (int i = 0; i < testdata.ItemCount * testdata.KnapsackCount; i++)
{
if (i < INITIAL_GENOTYPE_PROBABILITY * testdata.ItemCount * testdata.KnapsackCount)
{
initialGenotype[i] = 1;
}
else
{
initialGenotype[i] = 0;
}
}
population = new KNPSpecimen[populationSize];
for (int i = 0; i < populationSize; i++)
{
sbyte[] shuffledGenotype = initialGenotype.OrderBy(x => rnd.Next()).ToArray(); //shuffle initial genotype
KNPSpecimen grandpa = new KNPSpecimen(shuffledGenotype, testdata);
grandpa.Genotype = grandpa.FixGenotype(shuffledGenotype);
population[i] = grandpa;
}
indexOfCurrentPopulation = 0;
indexOfBestPopulation = 0;
bestScore = double.MinValue;
return(population);
}
}//End of Mutation()
internal KNPSpecimen[] Selection()
{
KNPSpecimen[] newPopulation = new KNPSpecimen[populationSize];
for (int i = 0; i < populationSize; i++)
{
newPopulation[i] = Tournament(population, tournamentSize); //tournament selection method
//newPopulation[i] = Roulette(population); //Roulette selection method
//newPopulation[i] = RandomSpecimen(population); //'Random' selection method
}
return(newPopulation);
}//End of Selection()
