org.moeaframework.algorithm
Class PeriodicAction

java.lang.Object
  org.moeaframework.algorithm.PeriodicAction

All Implemented Interfaces:

Algorithm

Direct Known Subclasses:

AdaptiveTimeContinuation, Checkpoints, InstrumentedAlgorithm

public abstract class PeriodicAction
extends Object
implements Algorithm

Decorates an algorithm to perform some action periodically throughout the execution of the algorithm. Note that due to the underlying implementation of the algorithm, the action may be invoked less frequently than requested or not at all.

Nested Class Summary

static class

PeriodicAction.FrequencyType Defines the type of frequency.

Field Summary

protected Algorithm	algorithm The underlying algorithm being decorated.
protected int	frequency The frequency that the doAction() method is invoked.
protected PeriodicAction.FrequencyType	frequencyType The type of frequency.
protected int	iteration The number of invocations of the Algorithm.step() method.
protected int	lastInvocation The last invocation doAction() was invoked.

Constructor Summary

PeriodicAction(Algorithm algorithm, int frequency, PeriodicAction.FrequencyType frequencyType)
Decorates an algorithm to perform a period action.

Method Summary

abstract void	doAction() Invoked periodically by this class to perform some function.
void	evaluate(Solution solution) Evaluates the specified solution for the problem being solved by this algorithm.
int	getNumberOfEvaluations() Returns the number of times the evaluate method was invoked.
Problem	getProblem() Returns the problem being solved by this algorithm.
NondominatedPopulation	getResult() Returns the current best-known result.
Serializable	getState() Returns a Serializable object representing the internal state of this algorithm.
boolean	isTerminated() Returns true if this algorithm is terminated; false otherwise.
void	setState(Object state) Sets the internal state of of this algorithm.
void	step() Performs one logical step of this algorithm.
void	terminate() Terminates this algorithm.

Methods inherited from class java.lang.Object

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

Field Detail

algorithm

protected final Algorithm algorithm

The underlying algorithm being decorated.

frequency

protected final int frequency

The frequency that the doAction() method is invoked.

frequencyType

protected final PeriodicAction.FrequencyType frequencyType

The type of frequency.

iteration

protected int iteration

The number of invocations of the Algorithm.step() method. Only used if the frequency type is STEPS.

lastInvocation

protected int lastInvocation

The last invocation doAction() was invoked. Only used if the frequency type is STEPS.

Constructor Detail

PeriodicAction

public PeriodicAction(Algorithm algorithm,
                      int frequency,
                      PeriodicAction.FrequencyType frequencyType)

Decorates an algorithm to perform a period action.

Parameters:

algorithm - the algorithm being decorated

frequency - the frequency the doAction() method is invoked

frequencyType - the type of frequency

Method Detail

getProblem

public Problem getProblem()

Description copied from interface: Algorithm

Returns the problem being solved by this algorithm.

Specified by:

getProblem in interface Algorithm

Returns:

the problem being solved by this algorithm

getResult

public NondominatedPopulation getResult()

Description copied from interface: Algorithm

Returns the current best-known result.

Specified by:

getResult in interface Algorithm

Returns:

the current best-known result

step

public void step()

Description copied from interface: Algorithm

Performs one logical step of this algorithm. The amount of work performed depends on the implementation. One invocation of this method may produce one or many trial solutions.

This method should not be invoked when Algorithm.isTerminated() returns true.

Specified by:

step in interface Algorithm

evaluate

public void evaluate(Solution solution)

Description copied from interface: Algorithm

Evaluates the specified solution for the problem being solved by this algorithm.

Specified by:

evaluate in interface Algorithm

Parameters:

solution - the solution to be evaluated

See Also:

Problem.evaluate(Solution)

getNumberOfEvaluations

public int getNumberOfEvaluations()

Description copied from interface: Algorithm

Returns the number of times the evaluate method was invoked. This is the primary measure of runtime for optimization algorithms.

Specified by:

getNumberOfEvaluations in interface Algorithm

Returns:

the number of times the evaluate method was invoked

isTerminated

public boolean isTerminated()

Description copied from interface: Algorithm

Returns true if this algorithm is terminated; false otherwise.

Specified by:

isTerminated in interface Algorithm

Returns:

true if this algorithm is terminated; false otherwise

See Also:

Algorithm.terminate()

terminate

public void terminate()

Description copied from interface: Algorithm

Terminates this algorithm. Implementations should use this method to free any underlying resources; however, the Algorithm.getResult() and Algorithm.getNumberOfEvaluations() methods are still required to work after termination.

Specified by:

terminate in interface Algorithm

doAction

public abstract void doAction()

Invoked periodically by this class to perform some function. This function should not depend on the frequency that it is invoked, since it is not guaranteed that this method is invoked at any specific frequency and, in some cases, may not be invoked at all.

getState

public Serializable getState()
                      throws NotSerializableException

Description copied from interface: Algorithm

Returns a Serializable object representing the internal state of this algorithm.

Specified by:

getState in interface Algorithm

Returns:

a Serializable object representing the internal state of this algorithm

Throws:

NotSerializableException - if this algorithm does not support serialization

setState

public void setState(Object state)
              throws NotSerializableException

Description copied from interface: Algorithm

Sets the internal state of of this algorithm.

Specified by:

setState in interface Algorithm

Parameters:

state - the internal state of this algorithm

Throws:

NotSerializableException - if this algorithm does not support serialization