Package org.jacop.search

Class LDS<T extends Var>

java.lang.Object

org.jacop.search.LDS<T>

Type Parameters:

T - type of variable being used in the search.

All Implemented Interfaces:

ExitChildListener<T>

public class LDS<T extends Var>
extends java.lang.Object
implements ExitChildListener<T>

Defines functionality of limited discrepancy search. Plugin in this object to search to change your depth first search into limited discrepancy search.

Version:

4.8

Field Summary

Fields

Modifier and Type	Field	Description
(package private) ExitChildListener<T>[]	exitChildListeners
(package private) int	maxNoDiscrepancies
(package private) int	noDiscrepancies
(package private) boolean	recentExitingLeftChildGoingForDiscrepancy
(package private) boolean	recentExitingRightChild
(package private) boolean	timeOut

Constructor Summary

Constructors

Constructor	Description
LDS(int maxDiscrepancies)	The search will not be allowed to deviate more than maxDiscrepancies times from the heuristic (e.g.

Method Summary

Modifier and Type	Method	Description
boolean	leftChild(PrimitiveConstraint choice, boolean status)	It is executed after exiting the left child.
boolean	leftChild(T var, int value, boolean status)	It is executed after exiting the left child.
void	rightChild(PrimitiveConstraint choice, boolean status)	It is executed after exiting the right child.
void	rightChild(T var, int value, boolean status)	Exiting the right children requires reduction of the current number of discrepancies being used.
void	setChildrenListeners(ExitChildListener<T> child)	It adds one child listener.
void	setChildrenListeners(ExitChildListener<T>[] children)	It sets the children listeners for the current listener.

Methods inherited from class java.lang.Object

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

Field Detail

timeOut

boolean timeOut

noDiscrepancies

int noDiscrepancies

maxNoDiscrepancies

int maxNoDiscrepancies

recentExitingLeftChildGoingForDiscrepancy

boolean recentExitingLeftChildGoingForDiscrepancy

recentExitingRightChild

boolean recentExitingRightChild

exitChildListeners

ExitChildListener<T extends Var>[] exitChildListeners

Constructor Detail

LDS

public LDS(int maxDiscrepancies)

The search will not be allowed to deviate more than maxDiscrepancies times from the heuristic (e.g. variable and value ordering) in the search.

Parameters:

maxDiscrepancies - maximal number of discrepancies allowed.

Method Detail

leftChild

public boolean leftChild(T var,
                         int value,
                         boolean status)

It is executed after exiting the left child. The parameters specify the variable and value used in the choice point. The parameter status specifies the return code from the child. The return parameter of this function specifies if the search should continue undisturbed or exit the current search node with value false.

Specified by:

leftChild in interface ExitChildListener<T extends Var>

Parameters:

var - variable used in the choice point.

value - value used in the choice point.

status - true if the solution was found in the child subtree, false otherwise.

Returns:

true if the search should continue undisturbed, false if it should exit the current node with false

leftChild

public boolean leftChild(PrimitiveConstraint choice,
                         boolean status)

It is executed after exiting the left child. The parameters specify the choice point. The parameter status specifies the return code from the child. The return parameter of this function specifies if the search should continue undisturbed or exit the current search node with false. If the continuing to the right child will exceed the number of allowed discrepancies then this function will return false so the right child will not be explored.

Specified by:

leftChild in interface ExitChildListener<T extends Var>

Parameters:

choice - primitive constraint used as the base of the choice point.

status - true if the solution was found in the child subtree, false otherwise.

Returns:

true if the search should continue undisturbed to the right node, false if it should exit the current node with false

rightChild

public void rightChild(T var,
                       int value,
                       boolean status)

Exiting the right children requires reduction of the current number of discrepancies being used.

Specified by:

rightChild in interface ExitChildListener<T extends Var>

Parameters:

var - variable used in the choice point.

value - value used in the choice point.

status - true if the solution was found in the child subtree, false otherwise. exit the current node with false

rightChild

public void rightChild(PrimitiveConstraint choice,
                       boolean status)

Description copied from interface: ExitChildListener

It is executed after exiting the right child.

Specified by:

rightChild in interface ExitChildListener<T extends Var>

Parameters:

choice - primitive constraint used as the base of the choice point.

status - true if the solution was found in the child subtree, false otherwise. exit the current node with false

setChildrenListeners

public void setChildrenListeners(ExitChildListener<T>[] children)

Description copied from interface: ExitChildListener

It sets the children listeners for the current listener.

Specified by:

setChildrenListeners in interface ExitChildListener<T extends Var>

Parameters:

children - array containing children listeners.

setChildrenListeners

public void setChildrenListeners(ExitChildListener<T> child)

Description copied from interface: ExitChildListener

It adds one child listener.

Specified by:

setChildrenListeners in interface ExitChildListener<T extends Var>

Parameters:

child - added child listener.