Alldistinct (jacop 4.2.0 API)

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

```
public class Alldistinct
extends Constraint
```
Alldistinct constraint assures that all FDVs have different values. This implementation is based on Regin paper. It uses slightly modified Hopcroft-Karp algorithm to compute maximum matching. The value graph is analysed and Tarjan algorithm for finding strongly connected components is used. Maximum matching and Value Graph is stored as TimeStamp Mutable variables to minimize recomputation. Value graph is expensive in terms of memory usage. Use this constraint with care. One variable with domain 0..1000000 will make it use few MB already and kill the efficiency.

Version:

4.2

Author:

Radoslaw Szymanek and Krzysztof Kuchcinski

Field Summary

Fields
Modifier and Type	Field and Description
`int`	`consistencyChecks` It counts the number of executions of the consistency function.
`protected ArrayList<IntVar>`	`freeVariablesAtFailure`
`int`	`fullConsistencyPassesWithNarrowingEvent` It computes how many times did consistency execution has been re-executed due to narrowing event at the end of the consistency function.
`IntVar[]`	`list` It specifies all variables which have to have different values.
`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
`Alldistinct(ArrayList<? extends IntVar> list)` It constructs an alldistinct constraint.
`Alldistinct(IntVar[] list)` It constructs an alldistinct 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.
`int`	`getConsistencyPruningEvent(Var var)` It retrieves the pruning event which causes reevaluation of the constraint.
`Constraint`	`getGuideConstraint()` It specifies a constraint which if imposed by search will enhance propagation of this constraint.
`int`	`getGuideValue()` This function provides a value which if assigned to a variable returned by getGuideVariable() will enhance propagation of this constraint.
`Var`	`getGuideVariable()` This function provides a variable which assigned a value returned by will enhance propagation of this 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, 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
  - consistencyChecks
```
public int consistencyChecks
```
    It counts the number of executions of the consistency function.
  - fullConsistencyPassesWithNarrowingEvent
```
public int fullConsistencyPassesWithNarrowingEvent
```
    It computes how many times did consistency execution has been re-executed due to narrowing event at the end of the consistency function.
  - freeVariablesAtFailure
```
protected ArrayList<IntVar> freeVariablesAtFailure
```
  - list
```
public IntVar[] list
```
    It specifies all variables which have to have different values.
  - 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
  - Alldistinct
```
public Alldistinct(IntVar[] list)
```
    It constructs an alldistinct constraint.
    
    Parameters:
    
    list - an array of variables.
  - Alldistinct
```
public Alldistinct(ArrayList<? extends IntVar> list)
```
    It constructs an alldistinct constraint.
    
    Parameters:
    
    list - arraylist of 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.
  - 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.
  - 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
  - getGuideConstraint
```
public Constraint getGuideConstraint()
```
    Description copied from class: Constraint
    
    It specifies a constraint which if imposed by search will enhance propagation of this constraint.
    
    Overrides:
    
    getGuideConstraint in class Constraint
    
    Returns:
    
    Constraint enhancing propagation of this constraint.
  - getGuideValue
```
public int getGuideValue()
```
    Description copied from class: Constraint
    
    This function provides a value which if assigned to a variable returned by getGuideVariable() will enhance propagation of this constraint.
    
    Overrides:
    
    getGuideValue in class Constraint
    
    Returns:
    
    Value which is a base of enhancing constraint.
  - getGuideVariable
```
public Var getGuideVariable()
```
    Description copied from class: Constraint
    
    This function provides a variable which assigned a value returned by will enhance propagation of this constraint.
    
    Overrides:
    
    getGuideVariable in class Constraint
    
    Returns:
    
    Variable which is a base of enhancing 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 Alldistinct

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

consistencyChecks

fullConsistencyPassesWithNarrowingEvent

freeVariablesAtFailure

list

xmlAttributes

Constructor Detail

Alldistinct

Alldistinct

Method Detail

arguments

removeLevel

consistency

getConsistencyPruningEvent

impose

queueVariable

removeConstraint

satisfied

toString

getGuideConstraint

getGuideValue

getGuideVariable

increaseWeight