io.jenetics

Class EliteSelector<G extends Gene<?,G>,C extends Comparable<? super C>>

java.lang.Object

io.jenetics.EliteSelector<G,C>

All Implemented Interfaces:

Selector<G,C>

public class EliteSelector<G extends Gene<?,G>,C extends Comparable<? super C>>
extends Object
implements Selector<G,C>

The EliteSelector copies a small proportion of the fittest candidates, without changes, into the next generation. This may have a dramatic impact on performance by ensuring that the GA doesn't waste time re-discovering previously refused partial solutions. Individuals that are preserved through elitism remain eligible for selection as parents of the next generation. Elitism is also related with memory: remember the best solution found so far. A problem with elitism is that it may causes the GA to converge to a local optimum, so pure elitism is a race to the nearest local optimum.

final Selector<DoubleGene, Double> selector = new EliteSelector<>( // Number of best individuals preserved for next generation: elites 3, // Selector used for selecting rest of population. new RouletteWheelSelector<>() );

Since:

4.0

Version:

5.0

Author:

Franz Wilhelmstötter

Constructor Summary

Constructors

Constructor and Description
EliteSelector() Create a new elite selector with elite count 1 and the selector for selecting the rest of the population is initialized with TournamentSelector<>(3)
EliteSelector(int eliteCount) Create a new elite selector with the desired number of elites to be selected.
EliteSelector(int eliteCount, Selector<G,C> nonEliteSelector) Create a new elite selector with the desired number of elites to be selected and the selector used for selecting the rest of the population.
EliteSelector(Selector<G,C> nonEliteSelector) Create a new elite selector with selector used for selecting the rest of the population.

Method Summary

Modifier and Type	Method and Description
ISeq<Phenotype<G,C>>	select(Seq<Phenotype<G,C>> population, int count, Optimize opt) Select phenotypes from the Population.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

EliteSelector

public EliteSelector(int eliteCount,
                     Selector<G,C> nonEliteSelector)

Create a new elite selector with the desired number of elites to be selected and the selector used for selecting the rest of the population.

Parameters:

eliteCount - the desired number of elite individual to be selected

nonEliteSelector - the selector used for selecting the rest of the population

Throws:

IllegalArgumentException - if eliteCount < 1

NullPointerException - if the nonEliteSelector is null

EliteSelector

public EliteSelector(int eliteCount)

Create a new elite selector with the desired number of elites to be selected. The selector for selecting the rest of the population is initialized with TournamentSelector<>(3).

Parameters:

eliteCount - the desired number of elite individual to be selected

Throws:

IllegalArgumentException - if eliteCount < 1

See Also:

TournamentSelector

EliteSelector

public EliteSelector(Selector<G,C> nonEliteSelector)

Create a new elite selector with selector used for selecting the rest of the population. The elite count is set to 1.

Parameters:

nonEliteSelector - the selector used for selecting the rest of the population

Throws:

NullPointerException - if the nonEliteSelector is null

See Also:

TournamentSelector

EliteSelector

public EliteSelector()

Create a new elite selector with elite count 1 and the selector for selecting the rest of the population is initialized with TournamentSelector<>(3)

Method Detail

select

public ISeq<Phenotype<G,C>> select(Seq<Phenotype<G,C>> population,
                                   int count,
                                   Optimize opt)

Description copied from interface: Selector

Select phenotypes from the Population.

Specified by:

select in interface Selector<G extends Gene<?,G>,C extends Comparable<? super C>>

Parameters:

population - The population to select from.

count - The number of phenotypes to select.

opt - Determines whether the individuals with higher fitness values or lower fitness values must be selected. This parameter determines whether the GA maximizes or minimizes the fitness function.

Returns:

The selected phenotypes (a new Population).

toString

public String toString()

Overrides:

toString in class Object