org.moeaframework.core.operator.program
Class SubtreeCrossover

java.lang.Object
  org.moeaframework.core.operator.program.SubtreeCrossover

All Implemented Interfaces:

Variation

public class SubtreeCrossover
extends Object
implements Variation

Exchanges a randomly-selected subtree from one program with a compatible, randomly-selected subtree from another program.

This operator is type-safe.

Constructor Summary

SubtreeCrossover(double probability)
Constructs a new subtree crossover instance.

Method Summary

protected void	crossover(Program program1, Program program2, Rules rules) Applies subtree crossover to the programs.
Solution[]	evolve(Solution[] parents) Evolves one or more parent solutions (specified by getArity) and produces one or more child solutions.
int	getArity() Returns the number of solutions that must be supplied to the evolve method.

Methods inherited from class java.lang.Object

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

Constructor Detail

SubtreeCrossover

public SubtreeCrossover(double probability)

Constructs a new subtree crossover instance.

Parameters:

probability - the probability that subtree crossover is applied to a program

Method Detail

getArity

public int getArity()

Description copied from interface: Variation

Returns the number of solutions that must be supplied to the evolve method.

Specified by:

getArity in interface Variation

Returns:

the number of solutions that must be supplied to the evolve method

evolve

public Solution[] evolve(Solution[] parents)

Description copied from interface: Variation

Evolves one or more parent solutions (specified by getArity) and produces one or more child solutions. By contract, the parents must not be modified. The copy constructor should be used to create copies of the parents with these copies subsequently modified.

Specified by:

evolve in interface Variation

Parameters:

parents - the array of parent solutions

Returns:

an array of child solutions

crossover

protected void crossover(Program program1,
                         Program program2,
                         Rules rules)

Applies subtree crossover to the programs.

Parameters:

program1 - the first program, which is the parent program

program2 - the second program, which provides the replacement subtree

rules - the rules defining the program syntax