Module io.jenetics.ext

Package io.jenetics.ext

Class WeaselMutator<G extends Gene<?,G>,C extends Comparable<? super C>>

java.lang.Object

io.jenetics.AbstractAlterer<G,C>

io.jenetics.Mutator<G,C>

io.jenetics.ext.WeaselMutator<G,C>

Type Parameters:

G - the gene type

C - the fitness result type

All Implemented Interfaces:

Alterer<G,C>

public class WeaselMutator<G extends Gene<?,G>,C extends Comparable<? super C>>
extends Mutator<G,C>

Mutator implementation which is part of the Weasel program algorithm. The Weasel program is a thought experiment by Richard Dawkins to illustrate the functioning of the evolution: random mutation combined with non-random cumulative selection.

The mutator mutates the genes of every chromosome of every genotype in the population with the given mutation probability.

Engine setup for the Weasel program:

final Engine<CharacterGene, Integer> engine = Engine.builder(problem)
     // Set the 'WeaselSelector'.
    .selector(new WeaselSelector<>())
     // Disable survivors selector.
    .offspringFraction(1)
     // Set the 'WeaselMutator'.
    .alterers(new WeaselMutator<>(0.05))
    .build();

Since:

3.5

Version:

5.0

See Also:

• Weasel program
• WeaselSelector

Field Summary

Fields inherited from class io.jenetics.AbstractAlterer

_probability

Fields inherited from interface io.jenetics.Alterer

DEFAULT_ALTER_PROBABILITY

Constructor Summary

Constructors

Constructor	Description
WeaselMutator()	Create a new weasel mutator with the default mutation probability of 0.05.
WeaselMutator(double probability)	Create a new weasel mutator with the given mutation probability.

Method Summary

Modifier and Type	Method	Description
AltererResult<G,C>	alter(Seq<Phenotype<G,C>> population, long generation)	Concrete implementation of the alter method.
protected MutatorResult<Genotype<G>>	mutate(Genotype<G> genotype, double p, RandomGenerator random)	Mutates the given genotype.
String	toString()

Methods inherited from class io.jenetics.Mutator

mutate, mutate, mutate

Methods inherited from class io.jenetics.AbstractAlterer

probability

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface io.jenetics.Alterer

andThen, compose

Constructor Details

WeaselMutator

public WeaselMutator(double probability)

Create a new weasel mutator with the given mutation probability.

Parameters:

probability - the mutation probability

Throws:

IllegalArgumentException - if the probability is not in the valid range of [0, 1].

WeaselMutator

public WeaselMutator()

Create a new weasel mutator with the default mutation probability of 0.05.

Method Details

alter

public AltererResult<G,C> alter(Seq<Phenotype<G,C>> population,
 long generation)

Description copied from class: Mutator

Concrete implementation of the alter method. It uses the following mutation methods: Mutator.mutate(Phenotype, long, double, RandomGenerator), Mutator.mutate(Genotype, double, RandomGenerator), Mutator.mutate(Chromosome, double, RandomGenerator), Mutator.mutate(Gene, RandomGenerator), in this specific order.

Specified by:

alter in interface Alterer<G extends Gene<?,G>,C extends Comparable<? super C>>

Overrides:

alter in class Mutator<G extends Gene<?,G>,C extends Comparable<? super C>>

Parameters:

population - The Population to be altered. If the population is null or empty, nothing is altered.

generation - the date of birth (generation) of the altered phenotypes.

Returns:

the alter-result object, which contains the altered population and the alteration counts

See Also:

• Mutator.mutate(Phenotype, long, double, RandomGenerator)
• Mutator.mutate(Genotype, double, RandomGenerator)
• Mutator.mutate(Chromosome, double, RandomGenerator)
• Mutator.mutate(Gene, RandomGenerator)

mutate

protected MutatorResult<Genotype<G>> mutate(Genotype<G> genotype,
 double p,
 RandomGenerator random)

Description copied from class: Mutator

Mutates the given genotype.

Overrides:

mutate in class Mutator<G extends Gene<?,G>,C extends Comparable<? super C>>

Parameters:

genotype - the genotype to mutate

p - the mutation probability for the underlying genetic objects

random - the random engine used for the genotype mutation

Returns:

the mutation result

See Also:

• Mutator.mutate(Chromosome, double, RandomGenerator)
• Mutator.mutate(Gene, RandomGenerator)

toString

public String toString()

Overrides:

toString in class Mutator<G extends Gene<?,G>,C extends Comparable<? super C>>