public static Chromosome GetBest(GetFitnessDelegate getFitness, int targetLen, int optimalFitness,
IReadOnlyList <char> geneSet, DisplayDelegate display)
{
var bestParent = GenerateParent(geneSet, targetLen, getFitness);
display(bestParent);
if (bestParent.Fitness >= optimalFitness)
{
return(bestParent);
}
while (true)
{
var child = Mutate(bestParent, geneSet, getFitness);
if (bestParent.Fitness >= child.Fitness)
{
continue;
}
display(child);
if (child.Fitness >= optimalFitness)
{
return(child);
}
bestParent = child;
}
}
public static Chromosome <TGene, TFitness> GetBest(GetFitnessDelegate getFitness, int targetLen,
TFitness optimalFitness, IReadOnlyList <TGene> geneSet, DisplayDelegate display,
MutateGeneDelegate customMutate = null, CreateDelegate customCreate = null, int?maxAge = null)
{
Chromosome <TGene, TFitness> FnMutate(Chromosome <TGene, TFitness> parent) =>
customMutate == null
? Mutate(parent, geneSet, getFitness)
: MutateCustom(parent, customMutate, getFitness);
Chromosome <TGene, TFitness> FnGenerateParent()
{
if (customCreate == null)
{
return(GenerateParent(targetLen, geneSet, getFitness));
}
var genes = customCreate();
return(new Chromosome <TGene, TFitness>(genes, getFitness(genes)));
}
foreach (var improvement in GetImprovement(FnMutate, FnGenerateParent, maxAge))
{
display(improvement);
if (optimalFitness.CompareTo(improvement.Fitness) <= 0)
{
return(improvement);
}
}
throw new UnauthorizedAccessException();
}
private static Chromosome <TGene, TFitness> GenerateParent(int length, IReadOnlyList <TGene> geneSet,
GetFitnessDelegate getFitness)
{
var genes = Rand.RandomSample(geneSet, length);
var fitness = getFitness(genes);
var chromosome = new Chromosome <TGene, TFitness>(genes, fitness);
return(chromosome);
}
public static Chromosome <TGene, TFitness> Mutate(Chromosome <TGene, TFitness> parent, IReadOnlyList <TGene> geneSet,
GetFitnessDelegate getFitness)
{
var childGenes = parent.Genes.ToArray();
var index = Rand.Random.Next(parent.Genes.Count);
var randomSample = Rand.RandomSample(geneSet, 2);
var newGene = randomSample[0];
var alternate = randomSample[1];
childGenes[index] = newGene.Equals(childGenes[index]) ? alternate : newGene;
var fitness = getFitness(childGenes);
return(new Chromosome <TGene, TFitness>(childGenes, fitness));
}
public static Chromosome <TGene, TFitness> GetBest(GetFitnessDelegate getFitness, int targetLen,
TFitness optimalFitness, TGene[] geneSet, DisplayDelegate display)
{
Chromosome <TGene, TFitness> FnMutate(Chromosome <TGene, TFitness> parent) =>
Mutate(parent, geneSet, getFitness);
Chromosome <TGene, TFitness> FnGenerateParent() => GenerateParent(targetLen, geneSet, getFitness);
foreach (var improvment in GetImprovment(FnMutate, FnGenerateParent))
{
display(improvment);
if (optimalFitness.CompareTo(improvment.Fitness) <= 0)
{
return(improvment);
}
}
throw new Exception();
}
private static Chromosome <TGene, TFitness> MutateCustom(Chromosome <TGene, TFitness> parent,
MutateGeneDelegate customMutate, GetFitnessDelegate getFitness)
{
var childGenes = parent.Genes.ToList();
customMutate(childGenes);
var fitness = getFitness(childGenes);
return(new Chromosome <TGene, TFitness>(childGenes, fitness));
}
private static Chromosome Mutate(Chromosome parent, IReadOnlyList <char> geneSet, GetFitnessDelegate getFitness)
{
var childGenes = parent.Genes.ToCharArray();
var index = Rand.Random.Next(parent.Genes.Length);
var randomSample = Rand.RandomSample(geneSet, 2);
var newGene = randomSample[0];
var alternate = randomSample[1];
childGenes[index] = newGene == childGenes[index] ? alternate : newGene;
var genes = new string(childGenes);
var fitness = getFitness(genes);
return(new Chromosome(genes, fitness));
}
private static Chromosome GenerateParent(IReadOnlyList <char> geneSet, int length, GetFitnessDelegate getFitness)
{
var genes = string.Empty;
while (genes.Length < length)
{
var sampleSize = Math.Min(length - genes.Length, geneSet.Count);
genes += Rand.RandomSample(geneSet, sampleSize);
}
var fitness = getFitness(genes);
return(new Chromosome(genes, fitness));
}
private static Chromosome <TGene, TFitness> Crossover(IReadOnlyList <TGene> parentGenes, int index,
IList <Chromosome <TGene, TFitness> > parents, GetFitnessDelegate getFitness, CrossoverDelegate crossover,
MutateChromosomeDelegate mutate, GenerateParentDelegate generateParent)
{
var donorIndex = Rand.Random.Next(0, parents.Count);
if (donorIndex == index)
{
donorIndex = (donorIndex + 1) % parents.Count;
}
var childGenes = crossover(parentGenes, parents[donorIndex].Genes);
if (childGenes == null)
{
// parent and donor are indistinguishable
parents[donorIndex] = generateParent();
return(mutate(parents[index]));
}
var fitness = getFitness(childGenes);
return(new Chromosome <TGene, TFitness>(childGenes, fitness, Strategy.Crossover));
}
public static Chromosome <TGene, TFitness> GetBest(GetFitnessDelegate getFitness, int targetLen,
TFitness optimalFitness, IReadOnlyList <TGene> geneSet, DisplayDelegate display,
MutateGeneDelegate customMutate = null, CreateDelegate customCreate = null, int?maxAge = null,
int poolSize = 1, CrossoverDelegate crossover = null, int?maxSeconds = null)
{
Chromosome <TGene, TFitness> FnMutate(Chromosome <TGene, TFitness> parent) =>
customMutate == null
? Mutate(parent, geneSet, getFitness)
: MutateCustom(parent, customMutate, getFitness);
Chromosome <TGene, TFitness> FnGenerateParent()
{
if (customCreate == null)
{
return(GenerateParent(targetLen, geneSet, getFitness));
}
var genes = customCreate();
return(new Chromosome <TGene, TFitness>(genes, getFitness(genes), Strategy.Create));
}
var strategyLookup =
new Dictionary <Strategy, StrategyDelegate>
{
{ Strategy.Create, (parentGenes, index, parents) => FnGenerateParent() },
{ Strategy.Mutate, (parentGenes, index, parents) => FnMutate(parentGenes) },
{
Strategy.Crossover, (parentGenes, index, parents) => Crossover(parentGenes.Genes, index,
parents, getFitness, crossover, FnMutate, FnGenerateParent)
}
};
var usedStrategies =
new List <StrategyDelegate> {
strategyLookup[Strategy.Mutate]
};
if (crossover != null)
{
usedStrategies.Add(strategyLookup[Strategy.Crossover]);
}
Chromosome <TGene, TFitness> FnNewChild(Chromosome <TGene, TFitness> parent, int index,
List <Chromosome <TGene, TFitness> > parents) =>
crossover != null
? Rand.SelectItem(usedStrategies)(parent, index, parents)
: FnMutate(parent);
try
{
foreach (var improvement in GetImprovement(FnNewChild, FnGenerateParent, maxAge, poolSize, maxSeconds))
{
display(improvement);
var f = strategyLookup[improvement.Strategy];
usedStrategies.Add(f);
if (optimalFitness.CompareTo(improvement.Fitness) <= 0)
{
return(improvement);
}
}
}
catch (SearchTimeoutException exception)
{
display(exception.Improvement);
return(exception.Improvement);
}
throw new UnauthorizedAccessException();
}
public static Chromosome <TGene, TFitness> GenerateParent(int length, IReadOnlyList <TGene> geneSet, GetFitnessDelegate getFitness)
{
var genes = Rand.RandomSample(geneSet, length).ToArray();
var fit = getFitness(genes);
return(new Chromosome <TGene, TFitness>(genes, fit));
}
