Package org.opt4j.common.archive

Class AdaptiveGridArchive

java.lang.Object

org.opt4j.core.IndividualSet

org.opt4j.core.optimizer.Archive

org.opt4j.common.archive.AbstractArchive

org.opt4j.common.archive.BoundedArchive

org.opt4j.common.archive.AdaptiveGridArchive

All Implemented Interfaces:

Iterable<Individual>, Collection<Individual>, Set<Individual>

public class AdaptiveGridArchive
extends BoundedArchive

The AdaptiveGridArchive uses an adaptive grid in order to bound the size of the Archive.

See Also:

• "Properties of an Adaptive Archiving Algorithm for Storing Nondominated Vectors, J. Knowles, D. Corne, Transactions of Evolutionary Computation, Vol. 7, No. 2, April 2003"

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	AdaptiveGridArchive.Cell	A single AdaptiveGridArchive.Cell of the grid.

Field Summary

Fields

Modifier and Type	Field	Description
protected final Map<Long,AdaptiveGridArchive.Cell>	cells
protected int	dim
protected final int	div
protected final List<Individual>	extrema
protected boolean	isInit
protected double[]	lb
protected final Rand	random
protected double[]	ub

Fields inherited from class org.opt4j.common.archive.BoundedArchive

capacity

Fields inherited from class org.opt4j.core.IndividualSet

individuals, listeners

Constructor Summary

Constructors

Constructor	Description
AdaptiveGridArchive(int capacity, int div, Rand random)	Constructs an AdaptiveGridArchive.

Method Summary

Modifier and Type	Method	Description
protected void	addToCell(Iterable<Individual> individuals)	Adds all Individuals to theirs AdaptiveGridArchive.Cells and the AdaptiveGridArchive.Cell s to the core.optimizer.Archive.
protected boolean	determineBounds(Collection<Individual> individuals)	Determines the new bounds for the individuals and returns true if the bounds have changed.
protected AdaptiveGridArchive.Cell	getCell(Individual individual)	Returns the appropriate AdaptiveGridArchive.Cell for the given Individual.
protected AdaptiveGridArchive.Cell	getMostCrowdedCell()	Returns the most crowded AdaptiveGridArchive.Cell.
protected void	init(Individual individual)	Initialize the Archive.
boolean	remove(Object o)
protected void	removeFromCell(Individual individual)	Removes this Individual from its AdaptiveGridArchive.Cell and removes the AdaptiveGridArchive.Cell from the Archive if it is empty.
protected boolean	updateWithNondominated(Collection<Individual> candidates)	Adds new candidates which are already checked to be not Pareto-dominated by any other individual in this Archive.

Methods inherited from class org.opt4j.common.archive.BoundedArchive

addCheckedIndividual, addCheckedIndividuals, getCapacity, setCapacity

Methods inherited from class org.opt4j.common.archive.AbstractArchive

update

Methods inherited from class org.opt4j.core.optimizer.Archive

add, addAll, addAll, update

Methods inherited from class org.opt4j.core.IndividualSet

addListener, clear, contains, containsAll, isEmpty, iterator, removeAll, removeListener, retainAll, size, toArray, toArray

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream, toArray

Methods inherited from interface java.lang.Iterable

forEach

Methods inherited from interface java.util.Set

equals, hashCode, spliterator

Field Details

isInit

protected boolean isInit

div

protected final int div

random

protected final Rand random

cells

protected final Map<Long,AdaptiveGridArchive.Cell> cells

extrema

protected final List<Individual> extrema

lb

protected double[] lb

ub

protected double[] ub

dim

protected int dim

Constructor Details

AdaptiveGridArchive

@Inject
public AdaptiveGridArchive(int capacity,
 int div,
 Rand random)

Constructs an AdaptiveGridArchive.

Parameters:

capacity - the capacity

div - the divisions

random - the random number generator

Method Details

updateWithNondominated

protected boolean updateWithNondominated(Collection<Individual> candidates)

Description copied from class: AbstractArchive

Adds new candidates which are already checked to be not Pareto-dominated by any other individual in this Archive. All Individuals in the Archive which were dominated by the candidates have already been removed.

Specified by:

updateWithNondominated in class AbstractArchive

Parameters:

candidates - the non-dominated individuals which can be added

Returns:

true if one or more candidates are added to the archive

init

protected void init(Individual individual)

Initialize the Archive.

Parameters:

individual - one random individual

getCell

protected AdaptiveGridArchive.Cell getCell(Individual individual)

Returns the appropriate AdaptiveGridArchive.Cell for the given Individual.

Parameters:

individual - the individual

Returns:

the cell

getMostCrowdedCell

protected AdaptiveGridArchive.Cell getMostCrowdedCell()

Returns the most crowded AdaptiveGridArchive.Cell.

Returns:

the most crowded cell

remove

public boolean remove(Object o)

Specified by:

remove in interface Collection<Individual>

Specified by:

remove in interface Set<Individual>

Overrides:

remove in class IndividualSet

addToCell

protected void addToCell(Iterable<Individual> individuals)

Adds all Individuals to theirs AdaptiveGridArchive.Cells and the AdaptiveGridArchive.Cell s to the core.optimizer.Archive.

Parameters:

individuals - the individuals to be added

removeFromCell

protected void removeFromCell(Individual individual)

Removes this Individual from its AdaptiveGridArchive.Cell and removes the AdaptiveGridArchive.Cell from the Archive if it is empty.

Parameters:

individual - the individual to be removed

determineBounds

protected boolean determineBounds(Collection<Individual> individuals)

Determines the new bounds for the individuals and returns true if the bounds have changed.

Parameters:

individuals - the individuals

Returns:

true if the bounds have changed