org.jacop.set.constraints

Class ElementSet

java.lang.Object

org.jacop.constraints.DecomposedConstraint<Constraint>

org.jacop.constraints.Constraint

org.jacop.set.constraints.ElementSet

All Implemented Interfaces:

SatisfiedPresent

public class ElementSet
extends Constraint
implements SatisfiedPresent

It is an element constraint that make sure that set variable value has a domain equal to the index-th element of the supplied list of sets.

By default, indexing starts from 1, if it is required to be different for example starting from 0, then indexOffset must be specified to be equal to -1.

Version:

4.9

Author:

Radoslaw Szymanek, Krzysztof Kuchcinski and Robert Åkemalm

Field Summary

Fields

Modifier and Type	Field and Description
IntVar	index It specifies what element from the list of sets is equal to set variable value.
int	indexOffset It allows to offset the indexing.
IntDomain[]	list It specifies a list of sets from which one element will be made equal to set variable value.
SetVar	value It specifies the set variable which is equal to one of the sets from the list as indicated by int variable index.

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
ElementSet(IntVar index, IntDomain[] list, SetVar value) It constructs an elementSet constraint to restrict the domains of the variables index and value.
ElementSet(IntVar index, IntDomain[] list, SetVar value, int indexOffset) It constructs a constraint to restrict the domains of the variables index and value.

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.
int	getDefaultConsistencyPruningEvent()
boolean	satisfied() It checks if the constraint is satisfied.
String	toString() It produces a string representation of a constraint state.

Methods inherited from class org.jacop.constraints.Constraint

afc, arguments, cleanAfterFailure, decompose, getGuideConstraint, getGuideValue, getGuideVariable, grounded, grounded, id, impose, impose, imposeDecomposition, increaseWeight, intArrayToString, long2int, numberArgs, queueVariable, 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

Field Detail

index

public IntVar index

It specifies what element from the list of sets is equal to set variable value.

list

public IntDomain[] list

It specifies a list of sets from which one element will be made equal to set variable value.

value

public SetVar value

It specifies the set variable which is equal to one of the sets from the list as indicated by int variable index.

indexOffset

public int indexOffset

It allows to offset the indexing. By default the indexing starts from 1, if index variable starts from 0, and 0 denotes the first element then indexOffset should be set to -1.

Constructor Detail

ElementSet

public ElementSet(IntVar index,
                  IntDomain[] list,
                  SetVar value,
                  int indexOffset)

It constructs a constraint to restrict the domains of the variables index and value.

Parameters:

value - variable that is restricted to have the same elements as list[index].

list - array of sets that contains possible values for variable value.

index - variable that is restricted to be the index of sets for which list[index] == value.

indexOffset - the shift applied to the index variable.

ElementSet

public ElementSet(IntVar index,
                  IntDomain[] list,
                  SetVar value)

It constructs an elementSet constraint to restrict the domains of the variables index and value.

Parameters:

value - variable that is restricted to have the same elements as list[index].

list - array of sets that contains possible values for variable value.

index - variable that is restricted to be the index of sets for which list[index] == value.

Method Detail

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.

Overrides:

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)

getDefaultConsistencyPruningEvent

public int getDefaultConsistencyPruningEvent()

Specified by:

getDefaultConsistencyPruningEvent in class Constraint

satisfied

public boolean satisfied()

Description copied from interface: SatisfiedPresent

It checks if the constraint is satisfied. It can return false even if constraint is satisfied but not all variables in its scope are grounded. It needs to return true if all variables in its scope are grounded and constraint is satisfied.

Implementations of this interface for constraints that are not PrimitiveConstraint may require constraint imposition and consistency check as a requirement to work correctly.

Specified by:

satisfied in interface SatisfiedPresent

Returns:

true if constraint is possible to verify that it is satisfied.

toString

public String toString()

Description copied from class: Constraint

It produces a string representation of a constraint state.

Overrides:

toString in class Constraint