AmongVar (jacop 4.2.0 API)

java.lang.Object
- org.jacop.constraints.DecomposedConstraint
- - org.jacop.constraints.Constraint
  - - org.jacop.constraints.AmongVar

```
public class AmongVar
extends Constraint
```
Among constraint in its general form. It establishes the following relation. The given number N of X`s take values from the set specified by Y`s. This constraint significantly extends the algorithms presented in the literature as it does not use the decomposition into simpler constraints. Therefore as a result, it provides stronger pruning methods without noticeable increase in the execution time. The large part of the computation is reused across following executions of the consistency function. The strength of propagation algorithm is incomporable to BC.

Version:

4.2

Author:

Polina Makeeva and Radoslaw Szymanek

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`counter` Number of Among constraints created.
`static boolean`	`debugAll` It turns out printing debugging information.
`IntVar[]`	`listOfX` List of variables x which values are checked against values of variables y.
`IntVar[]`	`listOfY` It specifies what values we are counting in the list of x's.
`IntVar`	`n` It specifies the number of x variables equal to at least one value present in the list of y.
`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.Constraint
atomicExecution, consistencyPruningEvents, earlyTerminationOK, id, increaseWeight, numberArgs, numberId, trace

Fields inherited from class org.jacop.constraints.DecomposedConstraint
queueIndex

Constructor Summary

Constructors
Constructor and Description
`AmongVar(ArrayList<IntVar> listOfX, ArrayList<IntVar> listOfY, IntVar n)` It constructs an AmongVar constraint.
`AmongVar(IntVar[] listOfX, IntVar[] listOfY, IntVar n)` It constructs an AmongVar constraint.

Method Summary

All Methods Instance Methods Concrete Methods
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.
`void`	`consistencyForX(Store store)` Is called when all y are grounded and amongForSet is equivalent to simple version of Among.
`void`	`consistencyForY(Store store)` It is a function which makes Y consistent if all X's are grounded.
`void`	`consistencyWhen_LB0_EQ_UB0(Store store)` The number of x in lbsDom is equal to the number of X intersecting ubSDom.
`int`	`getConsistencyPruningEvent(Var var)` It retrieves the pruning event which causes reevaluation of the 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 var)` 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.
`void`	`removeLevel(int level)` This function is called in case of the backtrack, so a constraint can clear the queue of changed variables which is no longer valid.
`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
cleanAfterFailure, decompose, getGuideConstraint, getGuideValue, getGuideVariable, id, impose, imposeDecomposition, numberArgs, removeLevelLate, 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
  - debugAll
```
public static final boolean debugAll
```
    It turns out printing debugging information.
    
    See Also:
    
    Constant Field Values
  - counter
```
public static int counter
```
    Number of Among constraints created.
  - listOfX
```
public IntVar[] listOfX
```
    List of variables x which values are checked against values of variables y. Each x is counted only once as equal to one of the elements of list y.
  - listOfY
```
public IntVar[] listOfY
```
    It specifies what values we are counting in the list of x's.
  - n
```
public IntVar n
```
    It specifies the number of x variables equal to at least one value present in the list of y.
  - 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
  - AmongVar
```
public AmongVar(IntVar[] listOfX,
                IntVar[] listOfY,
                IntVar n)
```
    It constructs an AmongVar constraint.
    
    Parameters:
    
    listOfX - the list of variables whose equality to other set of variables we count
    
    listOfY - the list of variable to which equality is counted.
    
    n - how many variables from list x are equal to at least one variable from list y.
  - AmongVar
```
public AmongVar(ArrayList<IntVar> listOfX,
                ArrayList<IntVar> listOfY,
                IntVar n)
```
    It constructs an AmongVar constraint.
    
    Parameters:
    
    listOfX - the list of variables whose equality to other set of variables we count
    
    listOfY - the list of variable to which equality is counted.
    
    n - how many variables from list x are equal to at least one variable from list y.
- 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.
  - removeLevel
```
public void removeLevel(int level)
```
    Description copied from class: Constraint
    
    This function is called in case of the backtrack, so a constraint can clear the queue of changed variables which is no longer valid. This function is called *before* all timestamps, variables, mutablevariables have reverted to their previous value.
    
    Overrides:
    
    removeLevel in class Constraint
    
    Parameters:
    
    level - the level which is being removed.
  - consistencyForX
```
public void consistencyForX(Store store)
```
    Is called when all y are grounded and amongForSet is equivalent to simple version of Among.
    
    Parameters:
    
    store - constraint store in which context that consistency function is being executed.
  - consistencyWhen_LB0_EQ_UB0
```
public void consistencyWhen_LB0_EQ_UB0(Store store)
```
    The number of x in lbsDom is equal to the number of X intersecting ubSDom. 1) If there are not enough of y to cover future domain then fail 2)
    
    Parameters:
    
    store -
  - consistencyForY
```
public void consistencyForY(Store store)
```
    It is a function which makes Y consistent if all X's are grounded.
    
    Parameters:
    
    store - a constraint store in which context all prunings are executed.
  - 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)
  - 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.
  - 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

Class AmongVar

Field Summary

Fields inherited from class org.jacop.constraints.Constraint

Fields inherited from class org.jacop.constraints.DecomposedConstraint

Constructor Summary

Method Summary

Methods inherited from class org.jacop.constraints.Constraint

Methods inherited from class org.jacop.constraints.DecomposedConstraint

Methods inherited from class java.lang.Object

Field Detail

debugAll

counter

listOfX

listOfY

n

xmlAttributes

Constructor Detail

AmongVar

AmongVar

Method Detail

arguments

removeLevel

consistencyForX

consistencyWhen_LB0_EQ_UB0

consistencyForY

consistency

getConsistencyPruningEvent

impose

queueVariable

removeConstraint

satisfied

toString

increaseWeight