org.jacop.constraints

Class Linear

java.lang.Object

org.jacop.constraints.DecomposedConstraint

org.jacop.constraints.Constraint

org.jacop.constraints.PrimitiveConstraint

org.jacop.constraints.Linear

public class Linear
extends PrimitiveConstraint

Linear constraint implements the weighted summation over several variables . It provides the weighted sum from all variables on the list. The weights are integers.

Version:

3.1

Author:

Krzysztof Kuchcinski and Radoslaw Szymanek

Field Summary

Fields

Modifier and Type	Field and Description
IntVar[]	list It specifies a list of variables being summed.
byte	relationType It specifies what relations is used by this constraint
int	sum It specifies variable for the overall sum.
int[]	weights It specifies a list of weights associated with the variables being summed.
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.PrimitiveConstraint

notConsistencyPruningEvents

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
Linear(Store store, ArrayList<? extends IntVar> variables, ArrayList<Integer> weights, String rel, int sum) It constructs the constraint Linear.
Linear(Store store, IntVar[] list, int[] weights, String rel, int sum)

Method Summary

Modifier and Type	Method and Description
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.
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 var) This is a function called to indicate which variable in a scope of constraint has changed.
String	rel2String()
byte	relation(String r)
void	removeConstraint() It removes the constraint by removing this constraint from all variables.
void	removeLevelLate(int level) This function is called in case of the backtrack.
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.PrimitiveConstraint

include, setNotConsistencyPruningEvent

Methods inherited from class org.jacop.constraints.Constraint

cleanAfterFailure, decompose, getGuideConstraint, getGuideValue, getGuideVariable, id, impose, imposeDecomposition, numberArgs, removeLevel, 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

relationType

public byte relationType

It specifies what relations is used by this constraint

list

public IntVar[] list

It specifies a list of variables being summed.

weights

public int[] weights

It specifies a list of weights associated with the variables being summed.

sum

public int sum

It specifies variable for the overall sum.

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

Linear

public Linear(Store store,
              IntVar[] list,
              int[] weights,
              String rel,
              int sum)

Parameters:

list -

weights -

sum -

Linear

public Linear(Store store,
              ArrayList<? extends IntVar> variables,
              ArrayList<Integer> weights,
              String rel,
              int sum)

It constructs the constraint Linear.

Parameters:

variables - variables which are being multiplied by weights.

weights - weight for each variable.

sum - variable containing the sum of weighted variables.

Method Detail

arguments

public 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.

removeLevelLate

public void removeLevelLate(int level)

Description copied from class: Constraint

This function is called in case of the backtrack. It is called after all timestamps, variables, mutablevariables have reverted to their values *after* removing the level.

Overrides:

removeLevelLate in class Constraint

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.

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.

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)

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.

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.

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 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.

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.

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.

relation

public byte relation(String r)

rel2String

public String rel2String()

toString

public 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