Module io.jenetics.base

Package io.jenetics

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

java.lang.Object

io.jenetics.AbstractAlterer<G,C>

io.jenetics.Mutator<G,C>

io.jenetics.ShiftMutator<G,C>

All Implemented Interfaces:

Alterer<G,C>

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

The shift mutation applies mutation between two randomly chosen points. A random value between the two points splits the sequences of genes between the positions. The second sequence is then shifted in front of the first one. This mutation operator can be used for combinatorial problems, where no duplicated genes within a chromosome are allowed, e.g., for the TSP.

Since:

8.0

Version:

8.0

See Also:

• Elements of evolutionary algorithms. Computational intelligence: A methodological introduction (pp. 255–285).
• Mutator

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final record	ShiftMutator.Range	This class defines the Chromosome shift indexes.
static interface	ShiftMutator.RangeRandom	Functional interface for creating random shift ranges objects for shifting sequences of a given length.

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
ShiftMutator()	Default constructor, with default mutation probability (Alterer.DEFAULT_ALTER_PROBABILITY).
ShiftMutator(double probability)	Constructs an alterer with a given recombination probability.
ShiftMutator(ShiftMutator.RangeRandom random)	Constructs an alterer with a given shifter-random.
ShiftMutator(ShiftMutator.RangeRandom random, double probability)	Constructs an alterer with a given shifter-random and recombination probability.

Method Summary

Modifier and Type	Method	Description
protected MutatorResult<Chromosome<G>>	mutate(Chromosome<G> chromosome, double p, RandomGenerator random)	Splits the values between two points into two sequences and shifts the second one in front of the first one.

Methods inherited from class io.jenetics.Mutator

alter, mutate, mutate, mutate, toString

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

ShiftMutator

public ShiftMutator(ShiftMutator.RangeRandom random,
 double probability)

Constructs an alterer with a given shifter-random and recombination probability.

Parameters:

random - the ShiftMutator.Range generator.

probability - the crossover probability.

Throws:

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

ShiftMutator

public ShiftMutator(ShiftMutator.RangeRandom random)

Constructs an alterer with a given shifter-random.

Parameters:

random - the ShiftMutator.Range generator.

Throws:

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

ShiftMutator

public ShiftMutator(double probability)

Constructs an alterer with a given recombination probability.

Parameters:

probability - the crossover probability.

Throws:

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

ShiftMutator

public ShiftMutator()

Default constructor, with default mutation probability (Alterer.DEFAULT_ALTER_PROBABILITY).

Method Details

mutate

protected MutatorResult<Chromosome<G>> mutate(Chromosome<G> chromosome,
 double p,
 RandomGenerator random)

Splits the values between two points into two sequences and shifts the second one in front of the first one.

Overrides:

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

Parameters:

chromosome - the chromosome 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(Gene, RandomGenerator)