org.apache.commons.math3.genetics

Class OnePointCrossover<T>

java.lang.Object

org.apache.commons.math3.genetics.OnePointCrossover<T>

Type Parameters:

T - generic type of the AbstractListChromosomes for crossover

All Implemented Interfaces:

CrossoverPolicy

public class OnePointCrossover<T>
extends java.lang.Object
implements CrossoverPolicy

One point crossover policy. A random crossover point is selected and the first part from each parent is copied to the corresponding child, and the second parts are copied crosswise. Example:

 -C- denotes a crossover point
                   -C-                                 -C-
 p1 = (1 0 1 0 0 1  | 0 1 1)    X    p2 = (0 1 1 0 1 0  | 1 1 1)
      \------------/ \-----/              \------------/ \-----/
            ||         (*)                       ||        (**)
            VV         (**)                      VV        (*)
      /------------\ /-----\              /------------\ /-----\
 c1 = (1 0 1 0 0 1  | 1 1 1)    X    c2 = (0 1 1 0 1 0  | 0 1 1)
 

This policy works only on AbstractListChromosome, and therefore it is parameterized by T. Moreover, the chromosomes must have same lengths.

Since:

2.0

Constructor Summary

Constructors

Constructor and Description
OnePointCrossover()

Method Summary

Methods

Modifier and Type	Method and Description
private ChromosomePair	crossover(AbstractListChromosome<T> first, AbstractListChromosome<T> second) Helper for crossover(Chromosome, Chromosome).
ChromosomePair	crossover(Chromosome first, Chromosome second) Performs one point crossover.

Methods inherited from class java.lang.Object

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

Constructor Detail

OnePointCrossover

public OnePointCrossover()

Method Detail

crossover

public ChromosomePair crossover(Chromosome first,
                       Chromosome second)
                         throws DimensionMismatchException,
                                MathIllegalArgumentException

Performs one point crossover. A random crossover point is selected and the first part from each parent is copied to the corresponding child, and the second parts are copied crosswise. Example:

 -C- denotes a crossover point
                   -C-                                 -C-
 p1 = (1 0 1 0 0 1  | 0 1 1)    X    p2 = (0 1 1 0 1 0  | 1 1 1)
      \------------/ \-----/              \------------/ \-----/
            ||         (*)                       ||        (**)
            VV         (**)                      VV        (*)
      /------------\ /-----\              /------------\ /-----\
 c1 = (1 0 1 0 0 1  | 1 1 1)    X    c2 = (0 1 1 0 1 0  | 0 1 1)
 

Specified by:

crossover in interface CrossoverPolicy

Parameters:

first - first parent (p1)

second - second parent (p2)

Returns:

pair of two children (c1,c2)

Throws:

MathIllegalArgumentException - iff one of the chromosomes is not an instance of AbstractListChromosome

DimensionMismatchException - if the length of the two chromosomes is different

crossover

private ChromosomePair crossover(AbstractListChromosome<T> first,
                       AbstractListChromosome<T> second)
                          throws DimensionMismatchException

Helper for crossover(Chromosome, Chromosome). Performs the actual crossover.

Parameters:

first - the first chromosome.

second - the second chromosome.

Returns:

the pair of new chromosomes that resulted from the crossover.

Throws:

DimensionMismatchException - if the length of the two chromosomes is different