jenes.stage.operator

Class Mutator<T extends Chromosome>

java.lang.Object

jenes.stage.AbstractStage<T>

jenes.stage.operator.Operator<T>

jenes.stage.operator.Mutator<T>

Type Parameters:

T - The class of chromosomes to work with.

Direct Known Subclasses:

SimpleMutator, TSPMutator, TSPScrambleMutator, TSPScrambleMutator

public abstract class Mutator<T extends Chromosome>
extends Operator<T>

A generic mutation operator. The operation is executed according to a mutation probability.

The actual operator is implemented by subclassing this abstract class and providing the mutate(Individual) implementation: the method is required to mutate an Individual according to a mutation strategy. No new individual copies have to be created during the mutation operation: the individual specified at the mutate(Individual) will take parte to the output mutator population.

A Mutator.Statistics is associated to each mutator operator.

Since:

1.0

Version:

1.2

See Also:

Individual, Population

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	Mutator.Statistics A statistics object holding the number of mutation performed and the time spent to execute them.

Field Summary

Fields

Modifier and Type	Field and Description
protected double	probability The mutation probablility

Fields inherited from class jenes.stage.operator.Operator

random, statistics

Fields inherited from class jenes.stage.AbstractStage

biggerIsBetter, fitness, ga

Constructor Summary

Constructors

Constructor and Description
Mutator(double probability) Constructs a new mutator instance with the specified mutator probability

Method Summary

Methods

Modifier and Type	Method and Description
double	getProbability() Returns the mutator probability
protected abstract void	mutate(Individual<T> t) Mutates a single individual.
void	process(Population<T> in, Population<T> out) Processes the input population and tranforms it into the output population.
void	setProbability(double probability) Sets the mutator probability

Methods inherited from class jenes.stage.operator.Operator

getStatistics, updateStatistics

Methods inherited from class jenes.stage.AbstractStage

dispose, getFitness, init, isBiggerBetter, isFitnessChanged, setBiggerIsBetter, setBiggerIsBetter, setFitness, setFitness

Methods inherited from class java.lang.Object

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

Field Detail

probability

protected double probability

The mutation probablility

Constructor Detail

Mutator

public Mutator(double probability)

Constructs a new mutator instance with the specified mutator probability

Parameters:

probability - the mutator probability

Method Detail

getProbability

public double getProbability()

Returns the mutator probability

Returns:

the mutator probability

setProbability

public void setProbability(double probability)

Sets the mutator probability

Parameters:

probability - the new mutator probability

process

public final void process(Population<T> in,
           Population<T> out)
                   throws StageException

Description copied from class: AbstractStage

Processes the input population and tranforms it into the output population. Note: - Out population is made of recicled individuals. There is a need of new individuals to add only when there is a need to increase the population size. For pre-initalized individual just use setAs method. This is done for an efficient memory management. - A stage can modify the input population. So input passed to process method can be mutated when the process method ends.

Specified by:

process in class AbstractStage<T extends Chromosome>

Parameters:

in - the input population

out - the output population

Throws:

StageException

mutate

protected abstract void mutate(Individual<T> t)

Mutates a single individual. This abstract method is implemented according to a mutation policy

Parameters:

t - the individual to mutate