JaCoP.set.constraints
Class AeqB

java.lang.Object
  JaCoP.constraints.DecomposedConstraint
      JaCoP.constraints.Constraint
          JaCoP.constraints.PrimitiveConstraint
              JaCoP.set.constraints.AeqB

public class AeqB
extends PrimitiveConstraint

It creates an equality constraint to make sure that two set variables have the same value.

Version:

3.1

Author:

Radoslaw Szymanek and Krzysztof Kuchcinski

Field Summary

SetVar	a It specifies set variable a, which must be equal to set variable b.
SetVar	b It specifies set variable b, which must be equal to set variable a.
static java.lang.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 JaCoP.constraints.PrimitiveConstraint

notConsistencyPruningEvents

Fields inherited from class JaCoP.constraints.Constraint

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

Fields inherited from class JaCoP.constraints.DecomposedConstraint

queueIndex

Constructor Summary

AeqB(SetVar a, SetVar b)
It constructs an AeqB constraint to restrict the domain of the variables.

Method Summary

java.util.ArrayList<Var>	arguments() It returns the variables in a scope of the constraint.
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.
int	getNestedPruningEvent(Var var, boolean mode) It retrieves the pruning event for which any composed constraint which uses this constraint should be evaluated.
int	getNotConsistencyPruningEvent(Var var) It retrieves the pruning event which causes reevaluation of the constraint notConsistency() function.
java.lang.String	id() It gives the id string of a constraint.
void	impose(Store store) It imposes the constraint in a given store.
void	increaseWeight() It increases the weight of the variables in the constraint scope.
void	notConsistency(Store store) It makes pruning in such a way that constraint is notConsistent.
boolean	notSatisfied() It checks if constraint would be always not satisfied.
void	queueVariable(int level, Var variable) This is a function called to indicate which variable in a scope of constraint has changed.
void	removeConstraint() It removes the constraint by removing this constraint from all variables.
boolean	satisfied() It checks if the constraint is satisfied.
java.lang.String	toString() It produces a string representation of a constraint state.

Methods inherited from class JaCoP.constraints.PrimitiveConstraint

setNotConsistencyPruningEvent

Methods inherited from class JaCoP.constraints.Constraint

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

Methods inherited from class JaCoP.constraints.DecomposedConstraint

auxiliaryVariables, imposeDecomposition

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

a

public SetVar a

It specifies set variable a, which must be equal to set variable b.

b

public SetVar b

It specifies set variable b, which must be equal to set variable a.

xmlAttributes

public static java.lang.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

AeqB

public AeqB(SetVar a,
            SetVar b)

It constructs an AeqB constraint to restrict the domain of the variables.

Parameters:

a - variable a restricted to be equal to b.

b - variable b restricted to be equal to a.

Method Detail

arguments

public java.util.ArrayList<Var> arguments()

Description copied from class: Constraint

It returns the variables in a scope of the constraint.

Specified by:

arguments in class Constraint

Returns:

variables in a scope of the constraint.

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.

getConsistencyPruningEvent

public int getConsistencyPruningEvent(Var var)

Description copied from class: Constraint

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

Specified by:

getConsistencyPruningEvent in class Constraint

Parameters:

var - variable for which pruning event is retrieved

Returns:

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

getNotConsistencyPruningEvent

public int getNotConsistencyPruningEvent(Var var)

Description copied from class: PrimitiveConstraint

It retrieves the pruning event which causes reevaluation of the constraint notConsistency() function.

Specified by:

getNotConsistencyPruningEvent in class PrimitiveConstraint

Parameters:

var - for which pruning event is retrieved

Returns:

the int denoting the pruning event associated with given variable.

id

public java.lang.String id()

Description copied from class: Constraint

It gives the id string of a constraint.

Specified by:

id in class Constraint

Returns:

string id of the constraint.

impose

public void impose(Store store)

Description copied from class: Constraint

It imposes the constraint in a given store.

Specified by:

impose in class Constraint

Parameters:

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

notConsistency

public void notConsistency(Store store)

Description copied from class: PrimitiveConstraint

It makes pruning in such a way that constraint is notConsistent. It removes values which always belong to a solution.

Specified by:

notConsistency in class PrimitiveConstraint

Parameters:

store - the constraint store in which context the notConsistency technique is evaluated.

notSatisfied

public boolean notSatisfied()

Description copied from class: PrimitiveConstraint

It checks if constraint would be always not satisfied.

Specified by:

notSatisfied in class PrimitiveConstraint

Returns:

true if constraint must be notSatisfied, false otherwise.

removeConstraint

public void removeConstraint()

Description copied from class: Constraint

It removes the constraint by removing this constraint from all variables.

Specified by:

removeConstraint in class Constraint

satisfied

public boolean satisfied()

Description copied from class: Constraint

It checks if the constraint is satisfied. If this function is incorrectly implemented a constraint may not be satisfied in a solution.

Specified by:

satisfied in class Constraint

Returns:

true if the constraint is for certain satisfied, false otherwise.

getNestedPruningEvent

public int getNestedPruningEvent(Var var,
                                 boolean mode)

Description copied from class: PrimitiveConstraint

It retrieves the pruning event for which any composed constraint which uses this constraint should be evaluated. This events are the ones which can change satisfied status?

Specified by:

getNestedPruningEvent in class PrimitiveConstraint

Parameters:

var - for which pruning event is retrieved

mode - decides if pruning event for consistency or nonconsistency is required.

Returns:

pruning event associated with the given variable for a given consistency mode.

toString

public java.lang.String toString()

Description copied from class: Constraint

It produces a string representation of a constraint state.

Specified by:

toString in class Constraint

increaseWeight

public void increaseWeight()

Description copied from class: Constraint

It increases the weight of the variables in the constraint scope.

Specified by:

increaseWeight in class Constraint

queueVariable

public void queueVariable(int level,
                          Var variable)

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.

variable - variable which has changed.