org.chocosolver.solver.constraints.set

Class PropNbEmpty

java.lang.Object

org.chocosolver.solver.constraints.Propagator<Variable>

org.chocosolver.solver.constraints.set.PropNbEmpty

All Implemented Interfaces:

Serializable, Comparable<Propagator>, ICause, Identity

public class PropNbEmpty
extends Propagator<Variable>

Restricts the number of empty sets |{s in sets such that |s|=0}| = nbEmpty

Author:

Jean-Guillaume Fages

See Also:

Serialized Form

Field Summary

Fields inherited from class org.chocosolver.solver.constraints.Propagator

aCause, ACTIVE, constraint, LOGGER, NEW, PASSIVE, priority, reactToFineEvt, REIFIED, solver, vars

Constructor Summary

Constructors

Constructor and Description
PropNbEmpty(SetVar[] sets, IntVar nbEmpty) Restricts the number of empty sets |{s in sets such that |s|=0}| = nbEmpty

Method Summary

Methods

Modifier and Type	Method and Description
boolean	advise(int idxVarInProp, int mask) Advise a propagator of a modification occurring on one of its variables, and decide if this should be scheduled.
void	duplicate(Solver solver, gnu.trove.map.hash.THashMap<Object,Object> identitymap) Duplicate the current propagator.
void	filter()
int	getPropagationConditions(int vIdx) Return the specific mask indicating the variable events on which this Propagator object can react.
ESat	isEntailed() Check wether this is entailed according to the current state of its internal structure.
void	propagate(int evtmask) Call the main filtering algorithm to apply to the Domain of the Variable objects.
void	propagate(int v, int mask) Incremental filtering algorithm defined within the Propagator, called whenever the variable of index idxVarInProp has changed.

Methods inherited from class org.chocosolver.solver.constraints.Propagator

addVariable, arity, compareTo, contradiction, decNbPendingEvt, defineIn, dynPriority, flushPendingEvt, forcePropagate, getConstraint, getId, getNbPendingEvt, getNbVars, getPriority, getSolver, getVar, getVars, getVIndices, hashCode, incNbPendingEvt, isActive, isCompletelyInstantiated, isPassive, isReifiedAndSilent, isStateLess, reactToFineEvent, setActive, setPassive, setReifiedSilent, setReifiedTrue, setVIndices, toString, why

Methods inherited from class java.lang.Object

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

Constructor Detail

PropNbEmpty

public PropNbEmpty(SetVar[] sets,
           IntVar nbEmpty)

Restricts the number of empty sets |{s in sets such that |s|=0}| = nbEmpty

Parameters:

sets - array of set variables

nbEmpty - integer variable

Method Detail

advise

public boolean advise(int idxVarInProp,
             int mask)

Description copied from class: Propagator

Advise a propagator of a modification occurring on one of its variables, and decide if this should be scheduled. At least, this method SHOULD check the propagation condition of the event received. In addition, this method can be used to update internal state of this. This method can returns true even if the propagator is already scheduled.

Overrides:

advise in class Propagator<Variable>

Parameters:

idxVarInProp - index of the modified variable

mask - modification event mask

Returns:

true if this should be scheduled, false otherwise.

getPropagationConditions

public int getPropagationConditions(int vIdx)

Description copied from class: Propagator

Return the specific mask indicating the variable events on which this Propagator object can react.
Checks are made applying bitwise AND between the mask and the event. Reacts to any kind of event by default.

Overrides:

getPropagationConditions in class Propagator<Variable>

Parameters:

vIdx - index of the variable within the propagator

Returns:

int composed of REMOVE and/or INSTANTIATE and/or DECUPP and/or INCLOW

propagate

public void propagate(int evtmask)
               throws ContradictionException

Description copied from class: Propagator

Call the main filtering algorithm to apply to the Domain of the Variable objects. It considers the current state of this objects to remove some values from domains and/or instantiate some variables. Calling this method is done from 2 (and only 2) steps:
- at the initial propagation step,
- when involved in a reified constraint.
It should initialized the internal data structure and apply filtering algorithm from scratch.

Specified by:

propagate in class Propagator<Variable>

Parameters:

evtmask - type of propagation event this must consider.

Throws:

ContradictionException - when a contradiction occurs, like domain wipe out or other incoherencies.

propagate

public void propagate(int v,
             int mask)
               throws ContradictionException

Description copied from class: Propagator

Incremental filtering algorithm defined within the Propagator, called whenever the variable of index idxVarInProp has changed. This method calls a CUSTOM_PROPAGATION (coarse-grained) by default.

This method should be overridden if the argument reactToFineEvt is set to true in the constructor. Otherwise, it executes propagate(PropagatorEventType.CUSTOM_PROPAGATION.getStrengthenedMask());

Overrides:

propagate in class Propagator<Variable>

Parameters:

v - index of the variable var in this

mask - type of event

Throws:

ContradictionException - if a contradiction occurs

filter

public void filter()
            throws ContradictionException

Throws:

ContradictionException

isEntailed

public ESat isEntailed()

Description copied from class: Propagator

Check wether this is entailed according to the current state of its internal structure. At least, should check the satisfaction of this (when all is instantiated).

Specified by:

isEntailed in class Propagator<Variable>

Returns:

ESat.TRUE if entailed, ESat.FALSE if not entailed, ESat.UNDEFINED if unknown

duplicate

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

Description copied from class: Propagator

Duplicate the current propagator. A restriction is that the resolution process should have not begun yet. That's why state of the propagator may not be duplicated.

Overrides:

duplicate in class Propagator<Variable>

Parameters:

solver - the target solver

identitymap - a map to ensure uniqueness of objects