/// <summary>
/// Runs a random walk of n steps along a landscape defined by a crossover operator and returns its results.
/// </summary>
/// <param name="steps">Number of steps.</param>
/// <param name="searchOperator">Operator defining a neighbourhood.</param>
/// <returns></returns>
public RandomWalk RandomWalk(int steps, CrossoverOperator searchOperator)
{
RandomWalk statistics = new RandomWalk(steps);
Chromosome parent1 = ChromosomeFactory.RandomSolution(Problem.GeneCount(), Problem);
Chromosome parent2 = ChromosomeFactory.RandomSolution(Problem.GeneCount(), Problem);
bool firstParent = RandomGeneratorThreadSafe.NextBool();
Chromosome parent = (firstParent ? parent1 : parent2), child;
GatherData(parent, 0, statistics);
const int minPopSize = 8, maxPopSize = 15;
int popSize = RandomGeneratorThreadSafe.NextInt(minPopSize, maxPopSize);
Chromosome[] supportPopulation = new Chromosome[popSize];
for (int i = 0; i < popSize; ++i)
{
supportPopulation[i] = ChromosomeFactory.RandomSolution(Problem.GeneCount(), Problem);
}
IGene[] childGenes1, childGenes2;
for (int i = 0; i < steps; ++i)
{
searchOperator.Run(parent1.Genes, parent2.Genes, out childGenes1, out childGenes2);
child = ChromosomeFactory.MakeChromosome(Problem, RandomGeneratorThreadSafe.NextBool() ? childGenes1 : childGenes2);
GatherData(child, i, statistics);
parent1 = child;
parent2 = supportPopulation[RandomGeneratorThreadSafe.NextInt(popSize)];
}
return(statistics);
}
public override void Run(IGene[] genes)
{
int startPosition = RandomGeneratorThreadSafe.NextInt(genes.Length - 1);
int length = RandomGeneratorThreadSafe.NextInt(genes.Length - startPosition - 2) + 2;
Inverse(genes, startPosition, length);
}
public override List <Chromosome> Run(List <Chromosome> chromosomes, Parameters parameters)
{
int k = 3, index;
var chosenOnes = new Chromosome[chromosomes.Count];
var tournament = new Chromosome[k];
Chromosome winner = null;
for (int i = 0; i < chromosomes.Count; ++i)
{
for (int j = 0; j < k; ++j)
{
index = RandomGeneratorThreadSafe.NextInt(chromosomes.Count);
tournament[j] = chromosomes[index];
}
//if (parameters.FitnessStrategy == Fitness.FitnessStrategy.MAXIMIZE)
winner = tournament[0];
for (int j = 1; j < k; ++j)
{
if (parameters.Fitness.Get(tournament[j]) < parameters.Fitness.Get(winner))
{
winner = tournament[j];
}
}
// winner = tournament.Aggregate((c1, c2) => parameters.Fitness.Get(c1) < parameters.Fitness.Get(c2) ? c1 : c2);
chosenOnes[i] = (Chromosome)winner.Clone();
}
return(chosenOnes.ToList());
}
public override void Run(ref Chromosome solution)
{
int startPosition = RandomGeneratorThreadSafe.NextInt(solution.Genes.Length - 1);
int length = RandomGeneratorThreadSafe.NextInt(solution.Genes.Length - startPosition - 2) + 2;
Inverse(solution.Genes, startPosition, length);
solution.Refresh();
}
public override void Run(IGene[] genes)
{
int startIndex, destIndex, length;
RandomGeneratorThreadSafe.NextTwoDifferentInts(genes.Length - 1, out startIndex, out destIndex);
int upperLimit = startIndex > destIndex ? startIndex : destIndex;
length = RandomGeneratorThreadSafe.NextInt(1, genes.Length - upperLimit + 1);
Displace(genes, startIndex, destIndex, length);
}
public override void Run(ref Chromosome solution)
{
int startIndex, destIndex, length;
RandomGeneratorThreadSafe.NextTwoDifferentInts(solution.Genes.Length - 1, out startIndex, out destIndex);
int upperLimit = startIndex > destIndex ? startIndex : destIndex;
length = RandomGeneratorThreadSafe.NextInt(1, solution.Genes.Length - upperLimit + 1);
Displace(solution.Genes, startIndex, destIndex, length);
solution.Refresh();
}
public override void Run(IGene[] parent1, IGene[] parent2, out IGene[] child1, out IGene[] child2)
{
int customerCount = parent1.Count();
IGene[] c1 = new IGene[customerCount];
IGene[] c2 = new IGene[customerCount];
int slicePoint = RandomGeneratorThreadSafe.NextInt(customerCount);
DoCycleCrossover(parent1, parent2, c1, c2, slicePoint, true);
child1 = c1;
child2 = c2;
}
public static void Shuffle <T>(this IList <T> list)
{
int n = list.Count, k;
while (n > 1)
{
--n;
k = RandomGeneratorThreadSafe.NextInt(n + 1);
T value = list[k];
list[k] = list[n];
list[n] = value;
}
}
