Alldistinct (JaCoP 4.9.0 API)

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

All Implemented Interfaces:

SatisfiedPresent, Stateful, UsesQueueVariable
```
public class Alldistinct
extends Constraint
implements UsesQueueVariable, Stateful, SatisfiedPresent
```
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:

4.9

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.
`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.

Fields inherited from class org.jacop.constraints.Constraint
atomicExecution, consistencyPruningEvents, constraintScope, earlyTerminationOK, increaseWeight, numberId, scope, trace

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

Constructor Summary

Constructors
Constructor and Description
`Alldistinct(IntVar[] list)` It constructs an alldistinct constraint.
`Alldistinct(List<? extends IntVar> list)` It constructs an alldistinct constraint.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`consistency(Store store)` It is a (most probably incomplete) consistency function which removes the values from variables domains.
`int`	`getDefaultConsistencyPruningEvent()`
`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`	`queueVariable(int level, Var var)` This is a function called to indicate which variable in a scope of constraint has changed.
`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
afc, arguments, cleanAfterFailure, decompose, getConsistencyPruningEvent, grounded, grounded, id, impose, imposeDecomposition, increaseWeight, intArrayToString, long2int, numberArgs, removeConstraint, requiresMonotonicity, setConsistencyPruningEvent, setConstraintScope, setScope, setScope, setScope, setScope, setScope, setWatchedVariableGrounded, supplyGuideFeedback, 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

Methods inherited from interface org.jacop.api.Stateful
isStateful

- 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.
  - list
```
public IntVar[] list
```
    It specifies all variables which have to have different values.
- Constructor Detail
  - Alldistinct
```
public Alldistinct(IntVar[] list)
```
    It constructs an alldistinct constraint.
    
    Parameters:
    
    list - an array of variables.
  - Alldistinct
```
public Alldistinct(List<? extends IntVar> list)
```
    It constructs an alldistinct constraint.
    
    Parameters:
    
    list - arraylist of variables.
- Method Detail
  - removeLevel
```
public void removeLevel(int level)
```
    Description copied from interface: Stateful
    
    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.
    
    Specified by:
    
    removeLevel in interface Stateful
    
    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.
  - 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.
  - 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.
  - toString
```
public String toString()
```
    Description copied from class: Constraint
    
    It produces a string representation of a constraint state.
    
    Overrides:
    
    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.

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

Methods inherited from interface org.jacop.api.Stateful

Field Detail

consistencyChecks

fullConsistencyPassesWithNarrowingEvent

list

Constructor Detail

Alldistinct

Alldistinct

Method Detail

removeLevel

consistency

getDefaultConsistencyPruningEvent

impose

queueVariable

satisfied

toString

getGuideConstraint

getGuideValue

getGuideVariable