Package org.jacop.constraints

Class SumWeight

java.lang.Object

org.jacop.constraints.DecomposedConstraint<Constraint>

org.jacop.constraints.Constraint

org.jacop.constraints.SumWeight

All Implemented Interfaces:

RemoveLevelLate, SatisfiedPresent, UsesQueueVariable

public class SumWeight
extends Constraint
implements UsesQueueVariable, SatisfiedPresent, RemoveLevelLate

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

Use when number of variables is greater than 15, otherwise use LinearInt.

Version:

3.1

Field Summary

Fields

Modifier and Type	Field	Description
private boolean	backtrackHasOccured
protected long	equalTo	It specifies value to which SumWeight is equal to.
(package private) static java.util.concurrent.atomic.AtomicInteger	idNumber
protected IntVar[]	list	It specifies a list of variables being summed.
private long	lMax
private long[]	lMaxArray
private long	lMin
private long[]	lMinArray
private TimeStamp<java.lang.Integer>	nextGroundedPosition	The position for the next grounded variable.
private java.util.Map<Var,java.lang.Integer>	positionMaping
private TimeStamp<java.lang.Long>	sumGrounded	The sum of grounded variables.
(package private) java.util.LinkedHashSet<IntVar>	variableQueue
protected long[]	weights	It specifies a list of weights associated with the variables being summed.

Fields inherited from class org.jacop.constraints.Constraint

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

Fields inherited from class org.jacop.constraints.DecomposedConstraint

queueIndex

Constructor Summary

Constructors

Modifier	Constructor	Description
	SumWeight(java.util.List<? extends IntVar> variables, java.util.List<java.lang.Integer> weights, IntVar sum)	It constructs the constraint SumWeight.
	SumWeight(IntVar[] list, int[] weights, int equalTo)
	SumWeight(IntVar[] list, int[] weights, IntVar sum)
private	SumWeight(IntVar[] list, int[] weights, IntVar sum, int equalTo)

Method Summary

Modifier and Type	Method	Description
(package private) void	checkForOverflow()
void	consistency(Store store)	It is a (most probably incomplete) consistency function which removes the values from variables domains.
private long	divRoundDown(long a, long b)
private long	divRoundUp(long a, long b)
int	getDefaultConsistencyPruningEvent()
void	impose(Store store)	It imposes the constraint in a given store.
void	queueVariable(int level, Var var)	This is a function called to indicate which variable in a scope of constraint has changed.
void	removeLevelLate(int level)	This function is called in case of the backtrack.
boolean	satisfied()	It checks if the constraint is satisfied.
java.lang.String	toString()	It produces a string representation of a constraint state.
private void	treatChangedVariables()

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, toInt, toInt, 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

idNumber

static final java.util.concurrent.atomic.AtomicInteger idNumber

list

protected final IntVar[] list

It specifies a list of variables being summed.

weights

protected final long[] weights

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

equalTo

protected final long equalTo

It specifies value to which SumWeight is equal to.

sumGrounded

private TimeStamp<java.lang.Long> sumGrounded

The sum of grounded variables.

nextGroundedPosition

private TimeStamp<java.lang.Integer> nextGroundedPosition

The position for the next grounded variable.

variableQueue

java.util.LinkedHashSet<IntVar> variableQueue

lMin

private long lMin

lMax

private long lMax

lMinArray

private long[] lMinArray

lMaxArray

private long[] lMaxArray

positionMaping

private java.util.Map<Var,java.lang.Integer> positionMaping

backtrackHasOccured

private boolean backtrackHasOccured

Constructor Detail

SumWeight

public SumWeight(IntVar[] list,
                 int[] weights,
                 IntVar sum)

Parameters:

list - the list of varibales

weights - the list of weights

sum - the resulting sum

SumWeight

public SumWeight(IntVar[] list,
                 int[] weights,
                 int equalTo)

Parameters:

list - the list of varibales

weights - the list of weights

equalTo - the value to which SumWeight is equal to.

SumWeight

private SumWeight(IntVar[] list,
                  int[] weights,
                  IntVar sum,
                  int equalTo)

SumWeight

public SumWeight(java.util.List<? extends IntVar> variables,
                 java.util.List<java.lang.Integer> weights,
                 IntVar sum)

It constructs the constraint SumWeight.

Parameters:

variables - variables which are being multiplied by weights.

weights - weight for each variable.

sum - variable containing the sum of weighted variables.

Method Detail

removeLevelLate

public void removeLevelLate(int level)

Description copied from interface: RemoveLevelLate

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.

Specified by:

removeLevelLate in interface RemoveLevelLate

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.

divRoundDown

private long divRoundDown(long a,
                          long b)

divRoundUp

private long divRoundUp(long a,
                        long b)

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.

treatChangedVariables

private void treatChangedVariables()

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.

checkForOverflow

void checkForOverflow()

toString

public java.lang.String toString()

Description copied from class: Constraint

It produces a string representation of a constraint state.

Overrides:

toString in class Constraint