Package se.liu.ida.hefquin.engine.queryproc.impl.poptimizer.evolutionaryAlgorithm

Class TerminateByDistancePercBest

java.lang.Object

se.liu.ida.hefquin.engine.queryproc.impl.poptimizer.evolutionaryAlgorithm.TerminationCriterionBase

se.liu.ida.hefquin.engine.queryproc.impl.poptimizer.evolutionaryAlgorithm.TerminateByDistancePercBest

All Implemented Interfaces:

TerminationCriterion

public class TerminateByDistancePercBest
extends TerminationCriterionBase

Distance-based termination criterion: Termination is triggered when the relative distance between the cost of the best plan in the current generation and in the previous generation has not exceeded a specified distance threshold for a number of generations.

Field Summary

Fields

Modifier and Type	Field	Description
protected final double	percBestThreshold

Fields inherited from class se.liu.ida.hefquin.engine.queryproc.impl.poptimizer.evolutionaryAlgorithm.TerminationCriterionBase

nrGenerations

Constructor Summary

Constructors

Constructor	Description
TerminateByDistancePercBest(double percBestThreshold, LogicalPlan plan)

Method Summary

Modifier and Type	Method	Description
static TerminationCriterionFactory	getFactory(double percBestThreshold)
boolean	readyToTerminate(Generation currentGeneration, List<Generation> allPreviousGenerations)	Returns true if this termination criterion has been reached with the current generation.

Methods inherited from class se.liu.ida.hefquin.engine.queryproc.impl.poptimizer.evolutionaryAlgorithm.TerminationCriterionBase

calcFactorial, countNumOfOps

Methods inherited from class java.lang.Object

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

Field Details

percBestThreshold

protected final double percBestThreshold

Constructor Details

TerminateByDistancePercBest

public TerminateByDistancePercBest(double percBestThreshold,
 LogicalPlan plan)

Method Details

getFactory

public static TerminationCriterionFactory getFactory(double percBestThreshold)

readyToTerminate

public boolean readyToTerminate(Generation currentGeneration,
 List<Generation> allPreviousGenerations)

Description copied from interface: TerminationCriterion

Returns true if this termination criterion has been reached with the current generation.

Parameters:

currentGeneration - the current generation for which the termination criterion is test

allPreviousGenerations - a list of all previous generations, in the order in which they have been created