org.chocosolver.solver.constraints

Class Constraint

java.lang.Object

org.chocosolver.solver.constraints.Constraint

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

AllDifferent, Arithmetic, CostRegular, Cumulative, DistanceXYC, DistanceXYZ, GlobalCardinality, IntEqRealConstraint, Max, Member, Min, NogoodConstraint, NotMember, RealConstraint, ReificationConstraint, SatConstraint, Scalar, Times

public class Constraint
extends Object
implements Serializable

A Constraint is basically a set of Propagator. It can either be posted or reified

Since:

0.01

Version:

major revision 13/01/2014

Author:

Jean-Guillaume Fages, Xavier Lorca, Charles Prud'homme

See Also:

Variable, Propagator, IPropagationEngine, Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected String	name
protected Propagator[]	propagators

Constructor Summary

Constructors

Constructor and Description
Constraint(String name, Propagator... propagators) Make a new constraint defined as a set of given propagators

Method Summary

Methods

Modifier and Type	Method and Description
PropagatorPriority	computeMaxPriority()
void	duplicate(Solver solver, gnu.trove.map.hash.THashMap<Object,Object> identitymap) Duplicate the current constraint.
String	getName()
Constraint	getOpposite() Get/make the opposite constraint of this The default opposite constraint does not filter domains but fails if this constraint is satisfied
Propagator	getPropagator(int i)
Propagator[]	getPropagators() Return an array which contains the propagators declared in this.
boolean	isReified()
ESat	isSatisfied() Test if this Constraint object is satisfied, regarding its Propagators and its Variable current domains.
Constraint	makeOpposite() Make the opposite constraint of this BEWARE: this method should never be called by the user but it can be overridden to provide better constraint negations
BoolVar	reif() Get/make the boolean variable indicating whether the constraint is satisfied or not
void	reifyWith(BoolVar bool) Reifies the constraint with a boolean variable If the reified boolean variable already exists, an additional (equality) constraint is automatically posted.
void	setName(String newName) Changes the name of this constraint
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

propagators

protected final Propagator[] propagators

name

protected String name

Constructor Detail

Constraint

public Constraint(String name,
          Propagator... propagators)

Make a new constraint defined as a set of given propagators

Parameters:

name - name of the constraint

propagators - set of propagators defining the constraint

Method Detail

getPropagators

public Propagator[] getPropagators()

Return an array which contains the propagators declared in this.

Returns:

an array of Propagator.

getPropagator

public Propagator getPropagator(int i)

isSatisfied

public ESat isSatisfied()

Test if this Constraint object is satisfied, regarding its Propagators and its Variable current domains.

This method is called on each solution as a checker when assertions are enabled (-ea in VM parameters) It is also called for constraint reification (to state whether or not a constraint is satisfied)

The method calls entailment checks of this propagators

Returns:

ESat.FALSE if the constraint cannot be satisfied (from domain consideration), ESat.TRUE if whatever future decisions are, the constraint will be satisfied for sure (without propagating domain modifications) ESat.UNDIFINED otherwise (more decisions/filtering must be made before concluding about constraint satisfaction)

toString

public String toString()

Overrides:

toString in class Object

isReified

public final boolean isReified()

Returns:

true iff this constraint has been reified

reifyWith

public final void reifyWith(BoolVar bool)

Reifies the constraint with a boolean variable If the reified boolean variable already exists, an additional (equality) constraint is automatically posted.

Parameters:

bool - the variable to reify with

reif

public final BoolVar reif()

Get/make the boolean variable indicating whether the constraint is satisfied or not

Returns:

the boolean reifying the constraint

getOpposite

public final Constraint getOpposite()

Get/make the opposite constraint of this The default opposite constraint does not filter domains but fails if this constraint is satisfied

Returns:

the opposite constraint of this

makeOpposite

public Constraint makeOpposite()

Make the opposite constraint of this BEWARE: this method should never be called by the user but it can be overridden to provide better constraint negations

setName

public void setName(String newName)

Changes the name of this constraint

Parameters:

newName - the name of the constraint

getName

public String getName()

Returns:

the name of this constraint

computeMaxPriority

public PropagatorPriority computeMaxPriority()

Returns:

the maximum priority of a propagator of this constraint

duplicate

public void duplicate(Solver solver,
             gnu.trove.map.hash.THashMap<Object,Object> identitymap)

Duplicate the current constraint. The constraint is NOT posted into the solver.

Parameters:

solver - the target solver

identitymap - a map to ensure uniqueness of objects