Module org.cicirello.chips_n_salsa
Package org.cicirello.search.operators.reals

Class UniformCrossover<T extends RealVector>

java.lang.Object
org.cicirello.search.operators.reals.UniformCrossover<T>
Type Parameters:
T - The specific RealVector type, such as RealVector or BoundedRealVector.
All Implemented Interfaces:
Splittable<CrossoverOperator<T>>, CrossoverOperator<T>
public final class UniformCrossover<T extends RealVector> extends Object implements CrossoverOperator<T>
Implementation of uniform crossover, but for RealVectors. In uniform crossover, instead of a fixed number of cross points, the crossover operator is controlled by a parameter, p, that is the probability that the values at a position are exchanged between the two parents. If the length of the vectors is N, then N independent random decisions are made regarding whether to exchange each position between the parents in forming the children. The expected number of values exchanged between the parents during a single crossover event is thus p*N. The most common value for p=0.5, which leads to each child inheriting on average half of the values from each of the two parents. Uniform crossover originated for crossover of bit vectors within a genetic algorithm, but has been adapted here for vectors of doubles.

  • Constructor Details

    • UniformCrossover

      public UniformCrossover()
      Constructs a uniform crossover operator with a probability of exchanging each value of p=0.5.

    • UniformCrossover

      public UniformCrossover(double p)
      Constructs a uniform crossover operator.
      Parameters:
      p - The per-position probability of exchanging each value between the parents in forming the children. The expected number of values exchanged during a single call to cross(org.cicirello.search.representations.RealVector, org.cicirello.search.representations.RealVector) is thus p*N, where N is the length of the vector.

  • Method Details

    • cross

      public void cross(RealVector c1, RealVector c2)
      Performs a crossover for an evolutionary algorithm, such that crossover forms two children from two parents. Implementations of this method modify the parameters, transforming the parents into the children.

      Behavior is undefined if the RealVectors are of different lengths.

      Specified by:
      cross in interface CrossoverOperator<T extends RealVector>
      Parameters:
      c1 - A candidate solution subject to the crossover. This method changes the state of c1.
      c2 - A candidate solution subject to the crossover. This method changes the state of c2.

    • split

      public UniformCrossover<T> split()
      Description copied from interface: Splittable
      Generates a functionally identical copy of this object, for use in multithreaded implementations of search algorithms. The state of the object that is returned may or may not be identical to that of the original. Thus, this is a distinct concept from the functionality of the Copyable interface. Classes that implement this interface must ensure that the object returned performs the same functionality, and that it does not share any state data that would be either unsafe or inefficient for concurrent access by multiple threads. The split method is allowed to simply return the this reference, provided that it is both safe and efficient for multiple threads to share a single copy of the Splittable object. The intention is to provide a multithreaded search with the capability to provide spawned threads with their own distinct search operators. Such multithreaded algorithms can call the split method for each thread it spawns to generate a functionally identical copy of the operator, but with independent state.
      Specified by:
      split in interface Splittable<T extends RealVector>
      Returns:
      A functionally identical copy of the object, or a reference to this if it is both safe and efficient for multiple threads to share a single instance of this Splittable object.