org.jgap.impl
Class CrossoverOperator

java.lang.Object
  org.jgap.BaseGeneticOperator
      org.jgap.impl.CrossoverOperator

All Implemented Interfaces:

java.io.Serializable, java.lang.Comparable, GeneticOperator

public class CrossoverOperator
extends BaseGeneticOperator
implements java.lang.Comparable

The crossover operator randomly selects two Chromosomes from the population and "mates" them by randomly picking a gene and then swapping that gene and all subsequent genes between the two Chromosomes. The two modified Chromosomes are then added to the list of candidate Chromosomes. If you work with CompositeGenes, this operator expects them to contain genes of the same type (e.g. IntegerGene). If you have mixed types, please provide your own crossover operator. This CrossoverOperator supports both fixed and dynamic crossover rates. A fixed rate is one specified at construction time by the user. This operation is performed 1/m_crossoverRate as many times as there are Chromosomes in the population. Another possibility is giving the crossover rate as a percentage. A dynamic rate is determined by this class on the fly if no fixed rate is provided.

Since:

1.0

See Also:

Serialized Form

Field Summary

Fields inherited from class org.jgap.BaseGeneticOperator

m_monitor, m_monitorActive

Constructor Summary

CrossoverOperator()
Constructs a new instance of this CrossoverOperator without a specified crossover rate, this results in dynamic crossover rate being turned off.

CrossoverOperator(Configuration a_configuration)
Constructs a new instance of this CrossoverOperator without a specified crossover rate, this results in dynamic crossover rate being turned off.

CrossoverOperator(Configuration a_configuration, double a_crossoverRatePercentage)
Constructs a new instance of this CrossoverOperator with the given crossover rate.

CrossoverOperator(Configuration a_configuration, double a_crossoverRatePercentage, boolean a_allowFullCrossOver)
Constructs a new instance of this CrossoverOperator with the given crossover rate.

CrossoverOperator(Configuration a_configuration, double a_crossoverRatePercentage, boolean a_allowFullCrossOver, boolean a_xoverNewAge)
Constructs a new instance of this CrossoverOperator with the given crossover rate.

CrossoverOperator(Configuration a_configuration, int a_desiredCrossoverRate)
Constructs a new instance of this CrossoverOperator with the given crossover rate.

CrossoverOperator(Configuration a_configuration, int a_desiredCrossoverRate, boolean a_allowFullCrossOver)
Constructs a new instance of this CrossoverOperator with the given crossover rate.

CrossoverOperator(Configuration a_configuration, int a_desiredCrossoverRate, boolean a_allowFullCrossOver, boolean a_xoverNewAge)
Constructs a new instance of this CrossoverOperator with the given crossover rate.

CrossoverOperator(Configuration a_configuration, IUniversalRateCalculator a_crossoverRateCalculator)
Constructs a new instance of this CrossoverOperator with a specified crossover rate calculator, which results in dynamic crossover being turned on.

CrossoverOperator(Configuration a_configuration, IUniversalRateCalculator a_crossoverRateCalculator, boolean a_allowFullCrossOver)
Constructs a new instance of this CrossoverOperator with a specified crossover rate calculator, which results in dynamic crossover being turned on.

Method Summary

int	compareTo(java.lang.Object a_other) Compares the given object to this one.
protected void	doCrossover(IChromosome firstMate, IChromosome secondMate, java.util.List a_candidateChromosomes, RandomGenerator generator)
int	getCrossOverRate()
double	getCrossOverRatePercent()
protected void	init() Initializes certain parameters.
boolean	isAllowFullCrossOver()
boolean	isXoverNewAge()
void	operate(Population a_population, java.util.List a_candidateChromosomes) Does the crossing over.
void	setAllowFullCrossOver(boolean a_allowFullXOver)
void	setXoverNewAge(boolean a_xoverNewAge)

Methods inherited from class org.jgap.BaseGeneticOperator

equals, getConfiguration

Methods inherited from class java.lang.Object

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

Constructor Detail

CrossoverOperator

public CrossoverOperator()
                  throws InvalidConfigurationException

Constructs a new instance of this CrossoverOperator without a specified crossover rate, this results in dynamic crossover rate being turned off. This means that the crossover rate will be fixed at populationsize/2.

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

Throws:

InvalidConfigurationException

Since:

2.0

CrossoverOperator

public CrossoverOperator(Configuration a_configuration)
                  throws InvalidConfigurationException

Constructs a new instance of this CrossoverOperator without a specified crossover rate, this results in dynamic crossover rate being turned off. This means that the crossover rate will be fixed at populationsize/2.

Parameters:

a_configuration - the configuration to use

Throws:

InvalidConfigurationException

Since:

3.0

CrossoverOperator

public CrossoverOperator(Configuration a_configuration,
                         IUniversalRateCalculator a_crossoverRateCalculator)
                  throws InvalidConfigurationException

Constructs a new instance of this CrossoverOperator with a specified crossover rate calculator, which results in dynamic crossover being turned on.

Parameters:

a_configuration - the configuration to use

a_crossoverRateCalculator - calculator for dynamic crossover rate computation

Throws:

InvalidConfigurationException

Since:

3.0 (since 2.0 without a_configuration)

CrossoverOperator

public CrossoverOperator(Configuration a_configuration,
                         IUniversalRateCalculator a_crossoverRateCalculator,
                         boolean a_allowFullCrossOver)
                  throws InvalidConfigurationException

Constructs a new instance of this CrossoverOperator with a specified crossover rate calculator, which results in dynamic crossover being turned on.

Parameters:

a_configuration - the configuration to use

a_crossoverRateCalculator - calculator for dynamic crossover rate computation

a_allowFullCrossOver - true: x-over before AND after x-over point, false: only x-over after x-over point

Throws:

InvalidConfigurationException

Since:

3.3.2

CrossoverOperator

public CrossoverOperator(Configuration a_configuration,
                         int a_desiredCrossoverRate)
                  throws InvalidConfigurationException

Constructs a new instance of this CrossoverOperator with the given crossover rate.

Parameters:

a_configuration - the configuration to use

a_desiredCrossoverRate - the desired rate of crossover

Throws:

InvalidConfigurationException

Since:

3.0 (since 2.0 without a_configuration)

CrossoverOperator

public CrossoverOperator(Configuration a_configuration,
                         int a_desiredCrossoverRate,
                         boolean a_allowFullCrossOver)
                  throws InvalidConfigurationException

Constructs a new instance of this CrossoverOperator with the given crossover rate. No new chromosomes are x-overed.

Parameters:

a_configuration - the configuration to use

a_desiredCrossoverRate - the desired rate of crossover

a_allowFullCrossOver - true: x-over before AND after x-over point, false: only x-over after x-over point

Throws:

InvalidConfigurationException

Since:

3.3.2

CrossoverOperator

public CrossoverOperator(Configuration a_configuration,
                         int a_desiredCrossoverRate,
                         boolean a_allowFullCrossOver,
                         boolean a_xoverNewAge)
                  throws InvalidConfigurationException

Constructs a new instance of this CrossoverOperator with the given crossover rate.

Parameters:

a_configuration - the configuration to use

a_desiredCrossoverRate - the desired rate of crossover

a_allowFullCrossOver - true: x-over before AND after x-over point, false: only x-over after x-over point

a_xoverNewAge - true: also x-over chromosomes with age of zero (newly created chromosomes)

Throws:

InvalidConfigurationException

Since:

3.3.2

CrossoverOperator

public CrossoverOperator(Configuration a_configuration,
                         double a_crossoverRatePercentage)
                  throws InvalidConfigurationException

Constructs a new instance of this CrossoverOperator with the given crossover rate. No new chromosomes are x-overed.

Parameters:

a_configuration - the configuration to use

a_crossoverRatePercentage - the desired rate of crossover in percentage of the population

Throws:

InvalidConfigurationException

Since:

3.0 (since 2.0 without a_configuration)

CrossoverOperator

public CrossoverOperator(Configuration a_configuration,
                         double a_crossoverRatePercentage,
                         boolean a_allowFullCrossOver)
                  throws InvalidConfigurationException

Constructs a new instance of this CrossoverOperator with the given crossover rate. No new chromosomes are x-overed.

Parameters:

a_configuration - the configuration to use

a_crossoverRatePercentage - the desired rate of crossover in percentage of the population

a_allowFullCrossOver - true: x-over before AND after x-over point, false: only x-over after x-over point

Throws:

InvalidConfigurationException

Since:

3.3.2.

CrossoverOperator

public CrossoverOperator(Configuration a_configuration,
                         double a_crossoverRatePercentage,
                         boolean a_allowFullCrossOver,
                         boolean a_xoverNewAge)
                  throws InvalidConfigurationException

Constructs a new instance of this CrossoverOperator with the given crossover rate.

Parameters:

a_configuration - the configuration to use

a_crossoverRatePercentage - the desired rate of crossover in percentage of the population

a_allowFullCrossOver - true: x-over before AND after x-over point, false: only x-over after x-over point

a_xoverNewAge - true: also x-over chromosomes with age of zero (newly created chromosomes)

Throws:

InvalidConfigurationException

Since:

3.3.2.

Method Detail

init

protected void init()

Initializes certain parameters.

Since:

3.3.2

operate

public void operate(Population a_population,
                    java.util.List a_candidateChromosomes)

Does the crossing over.

Specified by:

operate in interface GeneticOperator

Parameters:

a_population - the population of chromosomes from the current evolution prior to exposure to crossing over

a_candidateChromosomes - the pool of chromosomes that have been selected for the next evolved population

Since:

2.0

doCrossover

protected void doCrossover(IChromosome firstMate,
                           IChromosome secondMate,
                           java.util.List a_candidateChromosomes,
                           RandomGenerator generator)

compareTo

public int compareTo(java.lang.Object a_other)

Compares the given object to this one.

Specified by:

compareTo in interface java.lang.Comparable

Parameters:

a_other - the instance against which to compare this instance

Returns:

a negative number if this instance is "less than" the given instance, zero if they are equal to each other, and a positive number if this is "greater than" the given instance

Since:

2.6

setAllowFullCrossOver

public void setAllowFullCrossOver(boolean a_allowFullXOver)

Parameters:

a_allowFullXOver - x-over before and after a randomly chosen point

Since:

3.3.2

isAllowFullCrossOver

public boolean isAllowFullCrossOver()

Returns:

x-over before and after a randomly chosen x-over point

Since:

3.3.2

getCrossOverRate

public int getCrossOverRate()

Returns:

the crossover rate set

Since:

3.3.2

getCrossOverRatePercent

public double getCrossOverRatePercent()

Returns:

the crossover rate set

Since:

3.3.2

setXoverNewAge

public void setXoverNewAge(boolean a_xoverNewAge)

Parameters:

a_xoverNewAge - true: also x-over chromosomes with age of zero (newly created chromosomes)

Since:

3.3.2

isXoverNewAge

public boolean isXoverNewAge()

Returns:

a_xoverNewAge true: also x-over chromosomes with age of zero (newly created chromosomes)

Since:

3.3.2