Class NPointCrossover<T>

java.lang.Object
org.apache.commons.math3.genetics.NPointCrossover<T>
Type Parameters:
T - generic type of the AbstractListChromosomes for crossover
All Implemented Interfaces:
CrossoverPolicy

public class NPointCrossover<T> extends Object implements CrossoverPolicy
N-point crossover policy. For each iteration 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 (2-point crossover):
 -C- denotes a crossover point
           -C-       -C-                         -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                  VV      (*)        VV
      /----\ /--------\ /-----\             /----\ /--------\ /-----\
 c1 = (1 0  | 1 0 1 0  | 0 1 1)    X   c2 = (0 1  | 1 0 0 1  | 0 1 1)
 
This policy works only on AbstractListChromosome, and therefore it is parameterized by T. Moreover, the chromosomes must have same lengths.
Since:
3.1
  • Field Details

    • crossoverPoints

      private final int crossoverPoints
      The number of crossover points.
  • Constructor Details

    • NPointCrossover

      public NPointCrossover(int crossoverPoints) throws NotStrictlyPositiveException
      Creates a new NPointCrossover policy using the given number of points.

      Note: the number of crossover points must be < chromosome length - 1. This condition can only be checked at runtime, as the chromosome length is not known in advance.

      Parameters:
      crossoverPoints - the number of crossover points
      Throws:
      NotStrictlyPositiveException - if the number of crossoverPoints is not strictly positive
  • Method Details