Package io.jenetics

Class PartialAlterer<G extends Gene<?,​G>,​C extends Comparable<? super C>>

  • All Implemented Interfaces:
    Alterer<G,​C>
    public final class PartialAlterer<G extends Gene<?,​G>,​C extends Comparable<? super C>>
extends Object
implements Alterer<G,​C>
    This alterer wraps a given alterer which works on a given section of the genotype's chromosomes.
    // The genotype prototype, consisting of 4 chromosomes final Genotype<DoubleGene> gtf = Genotype.of( DoubleChromosome.of(0, 1), DoubleChromosome.of(1, 2), DoubleChromosome.of(2, 3), DoubleChromosome.of(3, 4) ); // Define the GA engine. final Engine<DoubleGene, Double> engine = Engine .builder(gt -> gt.getGene().doubleValue(), gtf) .selector(new RouletteWheelSelector<>()) .alterers( // The `Mutator` is used on chromosome with index 0 and 2. PartialAlterer.of(new Mutator<DoubleGene, Double>(), 0, 2), // The `MeanAlterer` is used on chromosome 3. PartialAlterer.of(new MeanAlterer<DoubleGene, Double>(), 3), // The `GaussianMutator` is used on all chromosomes. new GaussianMutator<>() ) .build();
    If you are using chromosome indices which are greater or equal than the number of chromosomes defined in the genotype, a CompletionException is thrown when the evolution stream is evaluated.
    Since:
    5.0
    Version:
    5.0
    Implementation Note:
    This alterer is slower than the performance of the wrapped alterer, because of the needed sectioning of the genotype.

    • Method Detail

      • alter

        public AltererResult<G,​C> alter​(Seq<Phenotype<G,​C>> population,
                                      long generation)
        Description copied from interface: Alterer
        Alters (recombine) a given population. If the population is empty, nothing is altered. The altered population is part of the returned AlterResult object.
        Specified by:
        alter in interface Alterer<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 count

      • of

        public static <G extends Gene<?,​G>,​C extends Comparable<? super C>> Alterer<G,​C> of​(Alterer<G,​C> alterer,
                                                                                                      int... indices)
        Wraps the given alterer, so that it will only work on chromosomes with the given chromosome indices.
        Type Parameters:
        G - the gene type
        C - the fitness value type
        Parameters:
        alterer - the alterer to user for altering the chromosomes with the given indices
        indices - the chromosomes indices (section)
        Returns:
        a wrapped alterer which only works for the given chromosome section
        Throws:
        NullPointerException - if the given indices array is null
        IllegalArgumentException - if the given indices array is empty
        NegativeArraySizeException - if one of the given indices is negative
        See Also:
        of(Alterer, IntRange)

      • of

        public static <G extends Gene<?,​G>,​C extends Comparable<? super C>> Alterer<G,​C> of​(Alterer<G,​C> alterer,
                                                                                                      IntRange section)
        Wraps the given alterer, so that it will only work on chromosomes with the given chromosome indices.
        Type Parameters:
        G - the gene type
        C - the fitness value type
        Parameters:
        alterer - the alterer to user for altering the chromosomes with the given indices
        section - the half-open chromosome index range [min, max)
        Returns:
        a wrapped alterer which only works for the given chromosome section
        Throws:
        NullPointerException - if the given indices array is null
        IllegalArgumentException - if the given indices array is empty
        NegativeArraySizeException - if one of the given indices is negative
        See Also:
        of(Alterer, int...)