org.jenetics

Interface Alterer<G extends Gene<?,G>,C extends Comparable<? super C>>

Type Parameters:

G - the gene type

C - the fitness function result type

All Known Implementing Classes:

AbstractAlterer, Crossover, GaussianMutator, IntermediateCrossover, LineCrossover, MeanAlterer, MultiPointCrossover, Mutator, PartiallyMatchedCrossover, Recombinator, SinglePointCrossover, SwapMutator, UniformCrossover

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface Alterer<G extends Gene<?,G>,C extends Comparable<? super C>>

The Alterer is responsible for the changing/recombining the Population. Alterers can be chained by appending a list of alterers with the Engine.Builder.alterers(Alterer, Alterer[]) method.

final Engine<DoubleGene, Double> engine = Engine .builder(gtf, ff) .alterers( new Crossover<>(0.1), new Mutator<>(0.05), new MeanAlterer<>(0.2)) .build(); final EvolutionStream<DoubleGene, Double> stream = engine.stream();

The order of the alterer calls is: Crossover, Mutation and MeanAlterer.

Since:

1.0

Version:

3.0

Author:

Franz Wilhelmstötter

Field Summary

Fields

Modifier and Type	Field and Description
static double	DEFAULT_ALTER_PROBABILITY The default alter probability: 0.2

Method Summary

Modifier and Type	Method and Description
int	alter(Population<G,C> population, long generation) Alters (recombine) a given population.
default Alterer<G,C>	andThen(Alterer<G,C> after) Returns a composed alterer that applies the this alterer to its input, and then applies the after alterer to the result.
default Alterer<G,C>	compose(Alterer<G,C> before) Returns a composed alterer that first applies the before alterer to its input, and then applies this alterer to the result.
static <G extends Gene<?,G>,C extends Comparable<? super C>> Alterer<G,C>	of(Alterer<G,C>... alterers) Combine the given alterers.

Field Detail

DEFAULT_ALTER_PROBABILITY

static final double DEFAULT_ALTER_PROBABILITY

The default alter probability: 0.2

See Also:

Constant Field Values

Method Detail

alter

int alter(Population<G,C> population,
          long generation)

Alters (recombine) a given population. If the population is empty, nothing is altered. The altering of the population is done in place; the given population is altered.

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 number of genes that has been altered.

Throws:

NullPointerException - if the given population is null.

compose

default Alterer<G,C> compose(Alterer<G,C> before)

Returns a composed alterer that first applies the before alterer to its input, and then applies this alterer to the result.

Parameters:

before - the alterer to apply first

Returns:

the new composed alterer

andThen

default Alterer<G,C> andThen(Alterer<G,C> after)

Returns a composed alterer that applies the this alterer to its input, and then applies the after alterer to the result.

Parameters:

after - the alterer to apply first

Returns:

the new composed alterer

of

@SafeVarargs
static <G extends Gene<?,G>,C extends Comparable<? super C>> Alterer<G,C> of(Alterer<G,C>... alterers)

Combine the given alterers.

Type Parameters:

G - the gene type

C - the fitness function result type

Parameters:

alterers - the alterers to combine.

Returns:

a new alterer which consists of the given one

Throws:

NullPointerException - if one of the alterers is null.