org.jacop.constraints

Class ExtensionalConflictVA

java.lang.Object

org.jacop.constraints.DecomposedConstraint<Constraint>

org.jacop.constraints.Constraint

org.jacop.constraints.ExtensionalConflictVA

All Implemented Interfaces:

Stateful, UsesQueueVariable

public class ExtensionalConflictVA
extends Constraint
implements UsesQueueVariable, Stateful

Extensional constraint assures that none of the tuples explicitly given is enforced in the relation.

This implementation tries to balance the usage of memory versus time efficiency.

Version:

4.9

Author:

Radoslaw Szymanek

Field Summary

Fields

Modifier and Type	Field and Description
IntVar[]	list It stores variables within this extensional constraint, order does matter.
int[][]	tuplesFromConstructor It specifies the tuples given in the constructor.

Fields inherited from class org.jacop.constraints.Constraint

atomicExecution, consistencyPruningEvents, constraintScope, earlyTerminationOK, increaseWeight, numberId, scope, trace

Fields inherited from class org.jacop.constraints.DecomposedConstraint

queueIndex

Constructor Summary

Constructors

Constructor and Description
ExtensionalConflictVA(IntVar[] list) Deprecated.
ExtensionalConflictVA(IntVar[] list, int[][] tuples) Constructor stores reference to tuples until imposition, any changes to tuples parameter will be reflected in the constraint behavior.
ExtensionalConflictVA(List<? extends IntVar> variables, int[][] tuples) The constructor does not create local copy of tuples array.

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.
protected int	findPosition(int value, int[] values)
int	getDefaultConsistencyPruningEvent()
void	impose(Store store) It imposes the constraint in a given store.
int	isDisallowed(int varPosition, int value, int[] t) It returns the position of disallowed tuple in the array of tuples for a given variable-value pair.
void	queueVariable(int level, Var var) This is a function called to indicate which variable in a scope of constraint has changed.
void	removeLevel(int level) It puts back tuples which have lost their support status at the level which is being removed.
int	seekInvalidPosition(int[] t) It finds the position at which the tuple is invalid.
int[]	seekSupportVA(int varPosition, int value) It seeks support tuple for a given variable and its value.
int[]	setFirstValid(int varPosition, int value) It computes the first valid tuple given restriction that a variable will be equal to a given value.
String	toString() It produces a string representation of a constraint state.

Methods inherited from class org.jacop.constraints.Constraint

afc, arguments, cleanAfterFailure, decompose, getConsistencyPruningEvent, getGuideConstraint, getGuideValue, getGuideVariable, grounded, grounded, id, impose, imposeDecomposition, increaseWeight, intArrayToString, long2int, numberArgs, removeConstraint, requiresMonotonicity, setConsistencyPruningEvent, setConstraintScope, setScope, setScope, setScope, setScope, setScope, setWatchedVariableGrounded, supplyGuideFeedback, updateAFC, watchedVariableGrounded

Methods inherited from class org.jacop.constraints.DecomposedConstraint

auxiliaryVariables, checkInput, checkInput, checkInputForDuplication, checkInputForDuplicationSkipSingletons, checkInputForNullness, checkInputForNullness, checkInputForNullness, derivative, getDubletonsSkipSingletons, imposeDecomposition

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.jacop.api.Stateful

isStateful

Field Detail

tuplesFromConstructor

public int[][] tuplesFromConstructor

It specifies the tuples given in the constructor.

list

public IntVar[] list

It stores variables within this extensional constraint, order does matter.

Constructor Detail

ExtensionalConflictVA

@Deprecated
public ExtensionalConflictVA(IntVar[] list)

Deprecated.

Partial constructor which stores variables involved in a constraint but does not get information about tuples yet. The tuples must set separately.

Parameters:

list - list of variables for constraint

ExtensionalConflictVA

public ExtensionalConflictVA(IntVar[] list,
                             int[][] tuples)

Constructor stores reference to tuples until imposition, any changes to tuples parameter will be reflected in the constraint behavior. Changes to tuples should not performed under any circumstances. The tuples array is not copied to save memory and time.

Parameters:

list - list of variables for the conflict constraint

tuples - list of forbidden tuples

ExtensionalConflictVA

public ExtensionalConflictVA(List<? extends IntVar> variables,
                             int[][] tuples)

The constructor does not create local copy of tuples array. Any changes to this array will reflect on constraint behavior. Most probably incorrect as other data structures will not change accordingly.

Parameters:

variables - the scope of the extensional conflict constraint.

tuples - the conflict (forbidden) tuples for that constraint.

Method Detail

seekSupportVA

public int[] seekSupportVA(int varPosition,
                           int value)

It seeks support tuple for a given variable and its value.

Parameters:

varPosition - variable for which the support is seeked.

value - value of the variable for which support is seeked.

Returns:

support tuple supporting varPosition-value pair.

setFirstValid

public int[] setFirstValid(int varPosition,
                           int value)

It computes the first valid tuple given restriction that a variable will be equal to a given value.

Parameters:

varPosition - the position of the variable.

value - the value of the variable.

Returns:

the smallest valid tuple supporting varPosition-value pair.

isDisallowed

public int isDisallowed(int varPosition,
                        int value,
                        int[] t)

It returns the position of disallowed tuple in the array of tuples for a given variable-value pair.

Parameters:

varPosition - variable for which we search for the forbidden tuple.

value - value for which we search for the forbidden tuple.

t - tuple which we check for forbidness.

Returns:

position of the forbidden tuple, -1 if it is not forbidden.

seekInvalidPosition

public int seekInvalidPosition(int[] t)

It finds the position at which the tuple is invalid. The value is not in the domain of the corresponding variable.

Parameters:

t - tuple being check for in-validity

Returns:

the position in the tuple at which the corresponding variable does not contain the value used by tuple, -1 if no invalid position exists.

removeLevel

public void removeLevel(int level)

It puts back tuples which have lost their support status at the level which is being removed.

Specified by:

removeLevel in interface Stateful

Parameters:

level - the level which is being removed.

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.

Specified by:

consistency in class Constraint

Parameters:

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

findPosition

protected int findPosition(int value,
                           int[] values)

getDefaultConsistencyPruningEvent

public int getDefaultConsistencyPruningEvent()

Specified by:

getDefaultConsistencyPruningEvent in class Constraint

impose

public void impose(Store store)

Description copied from class: Constraint

It imposes the constraint in a given store.

Overrides:

impose in class Constraint

Parameters:

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

queueVariable

public void queueVariable(int level,
                          Var var)

Description copied from class: Constraint

This is a function called to indicate which variable in a scope of constraint has changed. It also indicates a store level at which the change has occurred.

Overrides:

queueVariable in class Constraint

Parameters:

level - the level of the store at which the change has occurred.

var - variable which has changed.

toString

public String toString()

Description copied from class: Constraint

It produces a string representation of a constraint state.

Overrides:

toString in class Constraint