public BackPackIndividual BruteForce(BackPackEnvironment environment)
{
var possibleIndividuals = new List<BackPackIndividual>();
int genomeSize = environment.ComputeGenomeSize();
var chromosome = new int[genomeSize];
var posssibilitiesPerInt = environment.AvailableItems.Count > 31 ?
uint.MaxValue :
(uint)1 << environment.AvailableItems.Count; // 2^n
for (uint i = 0; i < posssibilitiesPerInt; i++)
{
for (int j = 0; j < genomeSize; j++)
{
chromosome[j] = (int)i;
var individual = new BackPackIndividual(environment);
individual.Genome.Chromosome = (int[])chromosome.Clone();
if (environment.Validate(individual))
{
possibleIndividuals.Add(individual);
}
}
}
return possibleIndividuals.Aggregate((a, b) => environment.RateFitness(a) > environment.RateFitness(b) ? a : b);
}
public void CrossIndividuals()
{
var backPack = new BackPack(volume: 1000);
var items = BackPackEnvironmentTest.RandomItems(8, backPack.Volume, 100);
var environment = new BackPackEnvironment(backPack, items);
var a = new BackPackIndividual(environment)
{ Genome = new BackPackIndividualGenome(new[]{0xF0}) }; //0b11110000
var b = new BackPackIndividual(environment)
{ Genome = new BackPackIndividualGenome(new[]{0xF}) }; //0b00001111
var child = new BackPackIndividual(environment)
{ Genome = new BackPackIndividualGenome(new[]{0xF7}) }; //0b11110111
Assert.AreEqual(child.Genome.Chromosome, a.Cross(b).Genome.Chromosome);
}
public void ValidateIndividual()
{
var backPack = new BackPack(volume: 1000);
var items = new List<BackPackItem>(
new [] {
new BackPackItem(200, 20),
new BackPackItem(300, 8),
new BackPackItem(500, 30),
new BackPackItem(150, 10)
});
var environment = new BackPackEnvironment(backPack, items);
var invalidIndividual = new BackPackIndividual(environment);
invalidIndividual.Genome.Chromosome = new[]{0xF}; //0xF=15=0b1111
var validIndividual = new BackPackIndividual(environment);
validIndividual.Genome.Chromosome = new[]{0x7}; //0x7=0b0111
Assert.IsFalse(environment.Validate(invalidIndividual));
Assert.IsTrue(environment.Validate(validIndividual));
}
public void RateFitnessOfRandomIndividuals()
{
const int tests = 3;
for (int n = 0; n < tests; n++)
{
var backPack = new BackPack(volume: random.Next(10000));
var items = RandomItems(random.Next(512), backPack.Volume, 100);
var environment = new BackPackEnvironment(backPack, items);
for (int i = 0; i <= items.Count; i++)
{
// compute chromosome
var chromosome = new int[environment.ComputeGenomeSize()];
// set every bit that encodes an Item at an index j < i
for (int j = 0; j < i; j++)
{
ChromosomeIndex index = environment.ComputeChromosomeIndex(j);
IntBitHelper.Set(ref chromosome[index.IntIndex], index.BitIndex);
}
var individual = new BackPackIndividual(environment)
{ Genome = new BackPackIndividualGenome(chromosome) };
// compute fitness with Item-List
double fitness = 0.0;
for (int j = 0; j < i; j++)
{
fitness += items[j].Value;
}
Assert.AreEqual(fitness, environment.RateFitness(individual));
}
}
}