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

Class TerminateByDiversityDistBest

java.lang.Object

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

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

All Implemented Interfaces:

TerminationCriterion

public class TerminateByDiversityDistBest
extends TerminationCriterionBase

Diversity-based termination criterion: Similar to TerminateByDiversityDistMax, but only the top-k plans with lowest cost within each generation are considered. Termination is triggered when the relative difference between the cost of the best plan and the top-k best plan within each generation has not exceeded a specified distance threshold for a number of generations.

Field Summary

Fields

Modifier and Type	Field	Description
protected final double	distBestThreshold
protected final double	topK

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

nrGenerations

Constructor Summary

Constructors

Constructor	Description
TerminateByDiversityDistBest(double distBestThreshold, double topK, LogicalPlan plan)

Method Summary

Modifier and Type	Method	Description
static TerminationCriterionFactory	getFactory(double distBestThreshold, double topK)
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

distBestThreshold

protected final double distBestThreshold

topK

protected final double topK

Constructor Details

TerminateByDiversityDistBest

public TerminateByDiversityDistBest(double distBestThreshold,
 double topK,
 LogicalPlan plan)

Method Details

getFactory

public static TerminationCriterionFactory getFactory(double distBestThreshold,
 double topK)

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