JaCoP.constraints
Class Element

java.lang.Object
  JaCoP.constraints.DecomposedConstraint
      JaCoP.constraints.Constraint
          JaCoP.constraints.Element

public class Element
extends Constraint

Element constraint implements the element/4 constraint (both with integer list and variables list). It defines a following relation variables[index - shift] = value. The default shift value is equal to zero. The first index in the variables list is equal to 1.

Author:

Krzysztof Kuchcinski and Radoslaw Szymanek

Field Summary

Fields inherited from class JaCoP.constraints.Constraint

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

Fields inherited from class JaCoP.constraints.DecomposedConstraint

queueIndex

Constructor Summary

Element(IntVar index, java.util.ArrayList<? extends IntVar> variables, IntVar value)
It constructs element constraint based on variables.

Element(IntVar index, java.util.ArrayList<? extends IntVar> variables, IntVar value, int shift)
It constructs element constraint based on variables.

Element(IntVar index, int[] values, IntVar value)
It constructs element constraint based on variables.

Element(IntVar index, int[] values, IntVar value, int shift)
It constructs element constraint based on variables.

Element(IntVar index, IntVar[] variables, IntVar value)

Element(IntVar index, IntVar[] variables, IntVar value, int shift)
It constructs element constraint based on 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.
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	queueVariable(int level, Var V) 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.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

Constructor Detail

Element

public Element(IntVar index,
               java.util.ArrayList<? extends IntVar> variables,
               IntVar value)

It constructs element constraint based on variables. The default shift value is equal 0.

Parameters:

index - index variable.

variables - list of variables.

value - variable to which index variable is equal to.

Element

public Element(IntVar index,
               java.util.ArrayList<? extends IntVar> variables,
               IntVar value,
               int shift)

It constructs element constraint based on variables.

Parameters:

index - index variable.

variables - variables list.

value - value variable.

shift - shift by which the index value is moved to the left.

Element

public Element(IntVar index,
               int[] values,
               IntVar value)

It constructs element constraint based on variables. The default shift value is equal 0.

Parameters:

index - index variable.

values - list of integers.

value - variable to which index variable is equal to.

Element

public Element(IntVar index,
               int[] values,
               IntVar value,
               int shift)

It constructs element constraint based on variables.

Parameters:

index - index variable.

values - integer list.

value - value variable.

shift - shift by which the index value is moved to the left.

Element

public Element(IntVar index,
               IntVar[] variables,
               IntVar value)

Parameters:

index -

variables -

value -

Element

public Element(IntVar index,
               IntVar[] variables,
               IntVar value,
               int shift)

It constructs element constraint based on variables.

Parameters:

index - index variable.

variables - variables list.

value - value variable.

shift - shift by which the index value is moved to the left.

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)

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.

queueVariable

public void queueVariable(int level,
                          Var V)

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.

V - variable which has changed.

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.

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