org.moeaframework.core.operator.program
Class PointMutation

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

All Implemented Interfaces:

Variation

public class PointMutation
extends Object
implements Variation

Mutates a program by randomly selecting nodes in the expression tree and replacing the node with a new, compatible, randomly-selected node.

This operator is type-safe.

Constructor Summary

PointMutation(double probability)
Constructs a new point mutation instance.

Method Summary

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.
protected void	mutate(Node node, Rules rules) Applies point mutation to the specified node.

Methods inherited from class java.lang.Object

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

Constructor Detail

PointMutation

public PointMutation(double probability)

Constructs a new point mutation instance.

Parameters:

probability - the probability of mutating a node in the tree

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

mutate

protected void mutate(Node node,
                      Rules rules)

Applies point mutation to the specified node.

Parameters:

node - the node undergoing point mutation

rules - the rules defining the program syntax