io.jenetics.engine

Class Engine.Builder<G extends Gene<?,G>,C extends Comparable<? super C>>

java.lang.Object

io.jenetics.engine.Engine.Builder<G,C>

Type Parameters:

G - the gene type

C - the fitness function result type

All Implemented Interfaces:

Copyable<Engine.Builder<G,C>>

Enclosing class:

Engine<G extends Gene<?,G>,C extends Comparable<? super C>>

public static final class Engine.Builder<G extends Gene<?,G>,C extends Comparable<? super C>>
extends Object
implements Copyable<Engine.Builder<G,C>>

Builder class for building GA Engine instances.

Since:

3.0

Version:

5.1

Author:

Franz Wilhelmstötter

See Also:

Engine

Constructor Summary

Constructors

Constructor and Description
Builder(Evaluator<G,C> evaluator, Factory<Genotype<G>> genotypeFactory) Create a new evolution Engine.Builder with the given fitness evaluator and genotype factory.

Method Summary

Modifier and Type	Method and Description
Engine.Builder<G,C>	alterers(Alterer<G,C> first, Alterer<G,C>... rest) The alterers used for alter the offspring population.
Engine<G,C>	build() Builds an new Engine instance from the set properties.
Engine.Builder<G,C>	clock(Clock clock) The clock used for calculating the execution durations.
Engine.Builder<G,C>	constraint(Constraint<G,C> constraint) The phenotype constraint is used for detecting invalid individuals and repairing them.
Engine.Builder<G,C>	copy() Create a new builder, with the current configuration.
Engine.Builder<G,C>	executor(Executor executor) The executor used by the engine.
Alterer<G,C>	getAlterers() Return the used Alterer of the GA.
Clock	getClock() Return the Clock the engine is using for measuring the execution time.
Constraint<G,C>	getConstraint() Return the constraint of the evolution problem.
Executor	getExecutor() Return the Executor the engine is using for executing the evolution steps.
Factory<Genotype<G>>	getGenotypeFactory() Return the used genotype Factory of the GA.
UnaryOperator<EvolutionResult<G,C>>	getMapper() Return the evolution result mapper.
long	getMaximalPhenotypeAge() Return the maximal allowed phenotype age.
double	getOffspringFraction() Return the offspring fraction.
Selector<G,C>	getOffspringSelector() Return the used offspring Selector of the GA.
Optimize	getOptimize() Return the optimization strategy.
int	getPopulationSize() Return the number of individuals of a population.
Selector<G,C>	getSurvivorsSelector() Return the used survivor Selector of the GA.
Engine.Builder<G,C>	mapping(Function<? super EvolutionResult<G,C>,EvolutionResult<G,C>> mapper) The result mapper, which allows to change the evolution result after each generation.
Engine.Builder<G,C>	maximalPhenotypeAge(long age) The maximal allowed age of a phenotype.
Engine.Builder<G,C>	maximizing() Set to a fitness maximizing strategy.
Engine.Builder<G,C>	minimizing() Set to a fitness minimizing strategy.
Engine.Builder<G,C>	offspringFraction(double fraction) The offspring fraction.
Engine.Builder<G,C>	offspringSelector(Selector<G,C> selector) The selector used for selecting the offspring population.
Engine.Builder<G,C>	offspringSize(int size) The number of offspring individuals.
Engine.Builder<G,C>	optimize(Optimize optimize) The optimization strategy used by the engine.
Engine.Builder<G,C>	populationSize(int size) The number of individuals which form the population.
Engine.Builder<G,C>	selector(Selector<G,C> selector) The selector used for selecting the survivors and offspring population.
Engine.Builder<G,C>	survivorsFraction(double fraction) The survivors fraction.
Engine.Builder<G,C>	survivorsSelector(Selector<G,C> selector) The selector used for selecting the survivors population.
Engine.Builder<G,C>	survivorsSize(int size) The number of survivors.

Methods inherited from class java.lang.Object

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

Constructor Detail

Builder

public Builder(Evaluator<G,C> evaluator,
               Factory<Genotype<G>> genotypeFactory)

Create a new evolution Engine.Builder with the given fitness evaluator and genotype factory. This is the most general way for creating an engine builder.

Parameters:

evaluator - the fitness evaluator

genotypeFactory - the genotype factory

Throws:

NullPointerException - if one of the arguments is null.

Since:

5.0

See Also:

Engine.builder(Function, Codec), Engine.builder(Function, Factory), Engine.builder(Problem), Engine.builder(Function, Chromosome, Chromosome[])

Method Detail

offspringSelector

public Engine.Builder<G,C> offspringSelector(Selector<G,C> selector)

The selector used for selecting the offspring population. Default values is set to TournamentSelector<>(3).

Parameters:

selector - used for selecting the offspring population

Returns:

this builder, for command chaining

survivorsSelector

public Engine.Builder<G,C> survivorsSelector(Selector<G,C> selector)

The selector used for selecting the survivors population. Default values is set to TournamentSelector<>(3).

Parameters:

selector - used for selecting survivors population

Returns:

this builder, for command chaining

selector

public Engine.Builder<G,C> selector(Selector<G,C> selector)

The selector used for selecting the survivors and offspring population. Default values is set to TournamentSelector<>(3).

Parameters:

selector - used for selecting survivors and offspring population

Returns:

this builder, for command chaining

alterers

@SafeVarargs
public final Engine.Builder<G,C> alterers(Alterer<G,C> first,
                                                       Alterer<G,C>... rest)

The alterers used for alter the offspring population. Default values is set to new SinglePointCrossover<>(0.2) followed by new Mutator<>(0.15).

Parameters:

first - the first alterer used for alter the offspring population

rest - the rest of the alterers used for alter the offspring population

Returns:

this builder, for command chaining

Throws:

NullPointerException - if one of the alterers is null.

constraint

public Engine.Builder<G,C> constraint(Constraint<G,C> constraint)

The phenotype constraint is used for detecting invalid individuals and repairing them.

Default implementation uses Phenotype::isValid for validating the phenotype.

Parameters:

constraint - phenotype constraint which can override the default implementation the Phenotype.isValid() method and repairs invalid phenotypes when needed.

Returns:

this builder, for command chaining

Since:

5.0

optimize

public Engine.Builder<G,C> optimize(Optimize optimize)

The optimization strategy used by the engine. Default values is set to Optimize.MAXIMUM.

Parameters:

optimize - the optimization strategy used by the engine

Returns:

this builder, for command chaining

maximizing

public Engine.Builder<G,C> maximizing()

Set to a fitness maximizing strategy.

Returns:

this builder, for command chaining

Since:

3.4

minimizing

public Engine.Builder<G,C> minimizing()

Set to a fitness minimizing strategy.

Returns:

this builder, for command chaining

Since:

3.4

offspringFraction

public Engine.Builder<G,C> offspringFraction(double fraction)

The offspring fraction. Default values is set to 0.6. This method call is equivalent to survivorsFraction(1 - offspringFraction) and will override any previously set survivors-fraction.

Parameters:

fraction - the offspring fraction

Returns:

this builder, for command chaining

Throws:

IllegalArgumentException - if the fraction is not within the range [0, 1].

See Also:

survivorsFraction(double)

survivorsFraction

public Engine.Builder<G,C> survivorsFraction(double fraction)

The survivors fraction. Default values is set to 0.4. This method call is equivalent to offspringFraction(1 - survivorsFraction) and will override any previously set offspring-fraction.

Parameters:

fraction - the survivors fraction

Returns:

this builder, for command chaining

Throws:

IllegalArgumentException - if the fraction is not within the range [0, 1].

Since:

3.8

See Also:

offspringFraction(double)

offspringSize

public Engine.Builder<G,C> offspringSize(int size)

The number of offspring individuals.

Parameters:

size - the number of offspring individuals.

Returns:

this builder, for command chaining

Throws:

IllegalArgumentException - if the size is not within the range [0, population-size].

Since:

3.8

survivorsSize

public Engine.Builder<G,C> survivorsSize(int size)

The number of survivors.

Parameters:

size - the number of survivors.

Returns:

this builder, for command chaining

Throws:

IllegalArgumentException - if the size is not within the range [0, population-size].

Since:

3.8

populationSize

public Engine.Builder<G,C> populationSize(int size)

The number of individuals which form the population. Default values is set to 50.

Parameters:

size - the number of individuals of a population

Returns:

this builder, for command chaining

Throws:

IllegalArgumentException - if size < 1

maximalPhenotypeAge

public Engine.Builder<G,C> maximalPhenotypeAge(long age)

The maximal allowed age of a phenotype. Default values is set to 70.

Parameters:

age - the maximal phenotype age

Returns:

this builder, for command chaining

Throws:

IllegalArgumentException - if age < 1

executor

public Engine.Builder<G,C> executor(Executor executor)

The executor used by the engine.

Parameters:

executor - the executor used by the engine

Returns:

this builder, for command chaining

clock

public Engine.Builder<G,C> clock(Clock clock)

The clock used for calculating the execution durations.

Parameters:

clock - the clock used for calculating the execution durations

Returns:

this builder, for command chaining

mapping

public Engine.Builder<G,C> mapping(Function<? super EvolutionResult<G,C>,EvolutionResult<G,C>> mapper)

The result mapper, which allows to change the evolution result after each generation.

Parameters:

mapper - the evolution result mapper

Returns:

this builder, for command chaining

Throws:

NullPointerException - if the given resultMapper is null

Since:

4.0

See Also:

EvolutionResult.toUniquePopulation()

build

public Engine<G,C> build()

Builds an new Engine instance from the set properties.

Returns:

an new Engine instance from the set properties

getAlterers

public Alterer<G,C> getAlterers()

Return the used Alterer of the GA.

Returns:

the used Alterer of the GA.

getClock

public Clock getClock()

Return the Clock the engine is using for measuring the execution time.

Returns:

the clock used for measuring the execution time

Since:

3.1

getExecutor

public Executor getExecutor()

Return the Executor the engine is using for executing the evolution steps.

Returns:

the executor used for performing the evolution steps

Since:

3.1

getGenotypeFactory

public Factory<Genotype<G>> getGenotypeFactory()

Return the used genotype Factory of the GA. The genotype factory is used for creating the initial population and new, random individuals when needed (as replacement for invalid and/or died genotypes).

Returns:

the used genotype Factory of the GA.

Since:

3.1

getConstraint

public Constraint<G,C> getConstraint()

Return the constraint of the evolution problem.

Returns:

the constraint of the evolution problem

Since:

5.0

getMaximalPhenotypeAge

public long getMaximalPhenotypeAge()

Return the maximal allowed phenotype age.

Returns:

the maximal allowed phenotype age

Since:

3.1

getOffspringFraction

public double getOffspringFraction()

Return the offspring fraction.

Returns:

the offspring fraction.

getOffspringSelector

public Selector<G,C> getOffspringSelector()

Return the used offspring Selector of the GA.

Returns:

the used offspring Selector of the GA.

Since:

3.1

getSurvivorsSelector

public Selector<G,C> getSurvivorsSelector()

Return the used survivor Selector of the GA.

Returns:

the used survivor Selector of the GA.

Since:

3.1

getOptimize

public Optimize getOptimize()

Return the optimization strategy.

Returns:

the optimization strategy

Since:

3.1

getPopulationSize

public int getPopulationSize()

Return the number of individuals of a population.

Returns:

the number of individuals of a population

Since:

3.1

getMapper

public UnaryOperator<EvolutionResult<G,C>> getMapper()

Return the evolution result mapper.

Returns:

the evolution result mapper

Since:

4.0

copy

public Engine.Builder<G,C> copy()

Create a new builder, with the current configuration.

Specified by:

copy in interface Copyable<Engine.Builder<G extends Gene<?,G>,C extends Comparable<? super C>>>

Returns:

a new builder, with the current configuration

Since:

3.1