org.moeaframework.core.spi
Class OperatorFactory

java.lang.Object
  org.moeaframework.core.spi.OperatorFactory

public class OperatorFactory
extends Object

Factory for creating operator instances. The table below shows the supported operators. The name and properties columns show the values accepted by getVariation(String, Properties, Problem).

Operator	Type	Name	Properties
SBX	Real	sbx	sbx.rate, sbx.distributionIndex
PM	Real	pm	pm.rate, pm.distributionIndex
UM	Real	um	um.rate
DifferentialEvolution	Real	de	de.crossoverRate, de.stepSize
PCX	Real	pcx	pcx.parents, pcx.offspring, pcx.eta, pcx.zeta
SPX	Real	spx	spx.parents, spx.offspring, spx.epsilon
UNDX	Real	undx	undx.parents, undx.offspring, undx.eta, undx.zeta
AdaptiveMetropolis	Real	am	am.parents, am.offspring, am.coefficient
HUX	Binary	hux	hux.rate
BitFlip	Binary	bf	bf.rate
PMX	Permutation	pmx	pmx.rate
Insertion	Permutation	insertion	insertion.rate
Swap	Permutation	swap	swap.rate
GrammarCrossover	Grammar	gx	gx.rate
GrammarMutation	Grammar	gm	gm.rate
SubtreeCrossover	Program	bx	bx.rate
PointMutation	Program	ptm	ptm.rate
OnePointCrossover	Any	1x	1x.rate
TwoPointCrossover	Any	2x	2x.rate
UniformCrossover	Any	ux	ux.rate

Operators can be combined by joining the two operator names with the plus sign, such as "sbx+pm". Not all operators can be joined this way. See CompoundVariation for the restrictions.

This class is thread safe.

Constructor Summary

OperatorFactory()
Constructs a new operator factory.

Method Summary

String	getDefaultMutation(Problem problem) Returns the name of the default mutation operator for the given problem.
String	getDefaultVariation(Problem problem) Returns the name of the default variation operator (e.g., crossover with mutation) for the given problem.
static OperatorFactory	getInstance() Returns the default operator factory.
Variation	getVariation(String name, Properties properties, Problem problem) Equivalent to calling getVariation(String, TypedProperties, Problem).
Variation	getVariation(String name, TypedProperties properties, Problem problem) Returns an instance of the variation operator with the specified name.
static void	setInstance(OperatorFactory instance) Sets the default operator factory.

Methods inherited from class java.lang.Object

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

Constructor Detail

OperatorFactory

public OperatorFactory()

Constructs a new operator factory.

Method Detail

getInstance

public static OperatorFactory getInstance()

Returns the default operator factory.

Returns:

the default operator factory

setInstance

public static void setInstance(OperatorFactory instance)

Sets the default operator factory.

Parameters:

instance - the default operator factory

getDefaultMutation

public String getDefaultMutation(Problem problem)

Returns the name of the default mutation operator for the given problem. Mixed types are currently not supported.

Parameters:

problem - the problem

Returns:

the name of the default mutation operator for the given problem

Throws:

ProviderNotFoundException - if no default mutation operator could be determined

getDefaultVariation

public String getDefaultVariation(Problem problem)

Returns the name of the default variation operator (e.g., crossover with mutation) for the given problem. Mixed types are currently not supported.

Parameters:

problem - the problem

Returns:

the name of the default variation operator for the given problem

Throws:

ProviderNotFoundException - if no default variation operator could be determined

getVariation

public Variation getVariation(String name,
                              Properties properties,
                              Problem problem)

Equivalent to calling getVariation(String, TypedProperties, Problem).

Parameters:

name - the name identifying the variation operator

properties - the implementation-specific properties

problem - the problem to be solved

Returns:

an instance of the variation operator with the specified name

Throws:

ProviderNotFoundException - if no provider for the algorithm is available

getVariation

public Variation getVariation(String name,
                              TypedProperties properties,
                              Problem problem)

Returns an instance of the variation operator with the specified name. This method must throw an ProviderNotFoundException if no suitable operator is found. If name is null, the factory should return a default variation operator appropriate for the problem.

Parameters:

name - the name identifying the variation operator

properties - the implementation-specific properties

problem - the problem to be solved

Returns:

an instance of the variation operator with the specified name

Throws:

ProviderNotFoundException - if no provider for the algorithm is available