org.jgap.impl

Class ThresholdSelector

java.lang.Object

org.jgap.NaturalSelector

org.jgap.NaturalSelectorExt

org.jgap.impl.ThresholdSelector

All Implemented Interfaces:

java.io.Serializable, Configurable, INaturalSelector

public class ThresholdSelector
extends NaturalSelectorExt

Implementation of a NaturalSelector that ensures a certain threshold of the best chromosomes are taken to the next generation.

Since:

2.0

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.jgap.NaturalSelector

NaturalSelector.AgeFitnessValueComparator, NaturalSelector.FitnessAgeValueComparator

Constructor Summary

Constructors

Constructor and Description
ThresholdSelector() Default constructor.
ThresholdSelector(Configuration a_config, double a_bestChromosomes_Percentage)

Method Summary

Modifier and Type	Method and Description
void	empty() Empty out the working pool of Chromosomes.
boolean	returnsUniqueChromosomes()
void	selectChromosomes(int a_howManyToSelect, Population a_to_pop) Select a given number of Chromosomes from the pool that will move on to the next generation population.

Methods inherited from class org.jgap.NaturalSelectorExt

equals, getDoubletteChromosomesAllowed, select, setDoubletteChromosomesAllowed

Methods inherited from class org.jgap.NaturalSelector

getConfiguration

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ThresholdSelector

public ThresholdSelector()
                  throws InvalidConfigurationException

Default constructor. Uses threshold of 30 percent.

Attention: The configuration used is the one set with the static method Genotype.setConfiguration.

Throws:

InvalidConfigurationException

Since:

2.6

ThresholdSelector

public ThresholdSelector(Configuration a_config,
                         double a_bestChromosomes_Percentage)
                  throws InvalidConfigurationException

Parameters:

a_config - the configuration to use

a_bestChromosomes_Percentage - indicates the number of best chromosomes from the population to be selected for granted. All other chromosomes will be selected in a random fashion. The value must be in the range from 0.0 to 1.0.

Throws:

InvalidConfigurationException

Since:

2.0

Method Detail

selectChromosomes

public void selectChromosomes(int a_howManyToSelect,
                              Population a_to_pop)

Select a given number of Chromosomes from the pool that will move on to the next generation population. This selection will be guided by the fitness values. The chromosomes with the best fitness value win.

Parameters:

a_howManyToSelect - the number of Chromosomes to select

a_to_pop - the population the Chromosomes will be added to

Since:

2.0

returnsUniqueChromosomes

public boolean returnsUniqueChromosomes()

Returns:

false as we allow to return the same chromosome multiple times

Since:

2.0

empty

public void empty()

Description copied from interface: INaturalSelector

Empty out the working pool of Chromosomes. This will be invoked after each evolution cycle so that the natural selector can be reused for the next one.