Module org.chocosolver

Package org.chocosolver.sat

Class PropNogoods

java.lang.Object

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

org.chocosolver.sat.PropNogoods

All Implemented Interfaces:

Comparable<Propagator>, ICause, Identity

public class PropNogoods
extends Propagator<IntVar>

A propagator to store and propagate no-goods. Created by cprudhom on 20/01/15. Project: choco.

Author:

Charles Prud'homme

Field Summary

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

ACTIVE, constraint, DEFAULT_EXPL, model, operations, OUTPUT_DEFAULT_EXPL, priority, reactToFineEvt, state, vars

Constructor Summary

Constructors

Constructor	Description
PropNogoods(Model model)	Create a (unique) propagator for no-goods recording and propagation.

Method Summary

Modifier and Type	Method	Description
void	addLearnt(int... lits)	Add learnt clause to no-goods store
boolean	addNogood(int p)	Add unit clause to no-goods store
boolean	addNogood(gnu.trove.list.TIntList lits)	Add unit clause to no-goods store
void	initialize()	Initializes this propagator
ESat	isEntailed()	Check wether this is entailed according to the current state of its internal structure.
int	Literal(IntVar ivar, int value, boolean eq)	Creates or returns if already existing, the literal corresponding to :
void	propagate(int evtmask)	Call the main filtering algorithm to apply to the Domain of the Variable objects.
void	propagate(int idxVarInProp, 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, defaultExplain, doFinePropagation, doFlush, doSchedule, doScheduleEvent, dynPriority, equals, explain, fails, forcePropagate, forcePropagationOnBacktrack, forEachIntVar, getConstraint, getId, getModel, getNbVars, getPosition, getPriority, getPropagationConditions, getVar, getVars, getVIndice, getVIndices, hashCode, isActive, isCompletelyInstantiated, isPassive, isReified, isReifiedAndSilent, isScheduled, isStateLess, linkVariables, reactToFineEvent, reifiedWith, setActive, setActive0, setPassive, setPosition, setReifiedSilent, setReifiedTrue, setVIndices, toString, unlinkVariables, unschedule

Methods inherited from class java.lang.Object

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

Constructor Detail

PropNogoods

public PropNogoods(Model model)

Create a (unique) propagator for no-goods recording and propagation.

Parameters:

model - the model that declares the propagator

Method Detail

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<IntVar>

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 idxVarInProp,
                      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<IntVar>

Parameters:

idxVarInProp - index of the variable var in this

mask - type of event

Throws:

ContradictionException - if a contradiction occurs

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<IntVar>

Returns:

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

initialize

public void initialize()

Initializes this propagator

Literal

public int Literal(IntVar ivar,
                   int value,
                   boolean eq)

Creates or returns if already existing, the literal corresponding to :

ivar (eq?"=":"<=") value

where "=" is selected if eq is true, "<=" otherwise.

The negation of the literal is managed outside.

Parameters:

ivar - an integer variable

value - a value

eq - set to true to select "=", to false to select "<=".

Returns:

the literal corresponding to ivar (eq?"=":"<=") value

addNogood

public boolean addNogood(int p)

Add unit clause to no-goods store

Parameters:

p - unit clause

Returns:

false if failure is detected

addNogood

public boolean addNogood(gnu.trove.list.TIntList lits)

Add unit clause to no-goods store

Parameters:

lits - clause

Returns:

false if failure is detected

addLearnt

public void addLearnt(int... lits)

Add learnt clause to no-goods store

Parameters:

lits - clause