org.jacop.constraints

Class Alldiff

java.lang.Object

org.jacop.constraints.DecomposedConstraint

org.jacop.constraints.Constraint

org.jacop.constraints.Alldifferent

org.jacop.constraints.Alldiff

Direct Known Subclasses:

Circuit, Subcircuit

public class Alldiff
extends Alldifferent

Alldiff constraint assures that all FDVs has different values. It uses bounds consistency technique as described in the paper by J.-F. Puget, "A fast algorithm for the bound consistency of alldiff constraints", in Proceedings of the Fifteenth National Conference on Artificial Intelligence (AAAI '98), 1998. It implements the method with time complexity O(n^2). Before using bounds consistency it calls consistency method from Alldifferent constraint. It extends basic functionality of Alldifferent constraint.

Version:

4.2

Author:

Krzysztof Kuchcinski and Radoslaw Szymanek

Field Summary

Fields

Modifier and Type	Field and Description
protected IntVar[]	listAlldiff
static String[]	xmlAttributes It specifies the arguments required to be saved by an XML format as well as the constructor being called to recreate an object from an XML format.

Fields inherited from class org.jacop.constraints.Alldifferent

grounded, list, positionMapping

Fields inherited from class org.jacop.constraints.Constraint

atomicExecution, consistencyPruningEvents, earlyTerminationOK, id, increaseWeight, numberArgs, numberId, trace

Fields inherited from class org.jacop.constraints.DecomposedConstraint

queueIndex

Constructor Summary

Constructors

Constructor and Description
Alldiff(ArrayList<? extends IntVar> variables) It constructs the alldiff constraint for the supplied variable.
Alldiff(IntVar[] variables) It constructs the alldiff constraint for the supplied variable.

Method Summary

Modifier and Type	Method and Description
void	consistency(Store store) It is a (most probably incomplete) consistency function which removes the values from variables domains.
int	getConsistencyPruningEvent(Var var) It retrieves the pruning event which causes reevaluation of the constraint.
void	impose(Store store) It imposes the constraint in a given store.
String	toString() It produces a string representation of a constraint state.

Methods inherited from class org.jacop.constraints.Alldifferent

arguments, increaseWeight, queueVariable, removeConstraint, satisfied

Methods inherited from class org.jacop.constraints.Constraint

cleanAfterFailure, decompose, getGuideConstraint, getGuideValue, getGuideVariable, id, impose, imposeDecomposition, numberArgs, removeLevel, removeLevelLate, requiresMonotonicity, setConsistencyPruningEvent, supplyGuideFeedback

Methods inherited from class org.jacop.constraints.DecomposedConstraint

auxiliaryVariables, derivative, imposeDecomposition

Methods inherited from class java.lang.Object

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

Field Detail

listAlldiff

protected IntVar[] listAlldiff

xmlAttributes

public static String[] xmlAttributes

It specifies the arguments required to be saved by an XML format as well as the constructor being called to recreate an object from an XML format.

Constructor Detail

Alldiff

public Alldiff(IntVar[] variables)

It constructs the alldiff constraint for the supplied variable.

Parameters:

variables - variables which are constrained to take different values.

Alldiff

public Alldiff(ArrayList<? extends IntVar> variables)

It constructs the alldiff constraint for the supplied variable.

Parameters:

variables - variables which are constrained to take different values.

Method Detail

getConsistencyPruningEvent

public int getConsistencyPruningEvent(Var var)

Description copied from class: Constraint

It retrieves the pruning event which causes reevaluation of the constraint.

Overrides:

getConsistencyPruningEvent in class Alldifferent

Parameters:

var - variable for which pruning event is retrieved

Returns:

it returns the int code of the pruning event (GROUND, BOUND, ANY, NONE)

impose

public void impose(Store store)

Description copied from class: Constraint

It imposes the constraint in a given store.

Overrides:

impose in class Alldifferent

Parameters:

store - the constraint store to which the constraint is imposed to.

consistency

public void consistency(Store store)

Description copied from class: Constraint

It is a (most probably incomplete) consistency function which removes the values from variables domains. Only values which do not have any support in a solution space are removed.

Overrides:

consistency in class Alldifferent

Parameters:

store - constraint store within which the constraint consistency is being checked.

toString

public String toString()

Description copied from class: Constraint

It produces a string representation of a constraint state.

Overrides:

toString in class Alldifferent