Module org.chocosolver.solver

Package org.chocosolver.solver.constraints.nary.sat

Class PropSat

java.lang.Object

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

org.chocosolver.solver.constraints.nary.sat.PropSat

All Implemented Interfaces:

Comparable<Propagator<Variable>>, ICause, Identity

public class PropSat
extends Propagator<Variable>

A propagator to deal with clauses and interface a MiniSat.

Since:

12/07/13

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
PropSat(Model model)	Create a (unique) propagator for clauses recording and propagation.

Method Summary

Modifier and Type	Method	Description
boolean	addClause(gnu.trove.list.TIntList lits)	Add a clause to SAT solver
void	addLearnt(int... lits)	Add learnt clause to SAT solver
void	afterAddingClauses()
void	beforeAddingClauses()
protected void	doBound(int i)
MiniSat	getMiniSat()
void	initialize()	Initializes this propagator
ESat	isEntailed()	Check wether this is entailed according to the current state of its internal structure.
void	lazyAddVar(Variable var)
int	makeBool(BoolVar expr)	Creates, or returns if already existing, the SAT variable corresponding to this CP variable.
int	makeIntEq(IntVar var, int val)	Creates, or returns if already existing, the SAT variable corresponding to the relationship var = val.
int	makeIntLe(IntVar var, int val)	Creates, or returns if already existing, the SAT variable corresponding to the relationship var ≤ val.
int	makeSetIn(SetVar var, int val)	Creates, or returns if already existing, the SAT variable corresponding to the relationship val ∈ var.
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.
protected ESat	value(int svar)

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, setEnabled, 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

PropSat

public PropSat(Model model)

Create a (unique) propagator for clauses recording and propagation.

Parameters:

model - the solver 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<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 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<Variable>

Parameters:

idxVarInProp - index of the variable var in this

mask - type of event

Throws:

ContradictionException - if a contradiction occurs

doBound

protected void doBound(int i)
                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

getMiniSat

public MiniSat getMiniSat()

Returns:

the underlying SAT solver

initialize

public void initialize()

Initializes this propagator

makeBool

public int makeBool(BoolVar expr)

Creates, or returns if already existing, the SAT variable corresponding to this CP variable.

Parameters:

expr - a boolean variable

Returns:

its SAT twin

makeIntEq

public int makeIntEq(IntVar var,
                     int val)

Creates, or returns if already existing, the SAT variable corresponding to the relationship var = val.

Parameters:

var - an integer variable

val - an integer

Returns:

its SAT twin

makeIntLe

public int makeIntLe(IntVar var,
                     int val)

Creates, or returns if already existing, the SAT variable corresponding to the relationship var ≤ val.

Parameters:

var - an integer variable

val - an integer

Returns:

its SAT twin

makeSetIn

public int makeSetIn(SetVar var,
                     int val)

Creates, or returns if already existing, the SAT variable corresponding to the relationship val ∈ var.

Parameters:

var - an integer variable

val - an integer

Returns:

its SAT twin

lazyAddVar

public void lazyAddVar(Variable var)

value

protected ESat value(int svar)

beforeAddingClauses

public void beforeAddingClauses()

afterAddingClauses

public void afterAddingClauses()

addClause

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

Add a clause to SAT solver

Parameters:

lits - clause

Returns:

false if failure is detected

addLearnt

public void addLearnt(int... lits)

Add learnt clause to SAT solver

Parameters:

lits - clause