Package org.chocosolver.sat
Class PropSat
- java.lang.Object
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- org.chocosolver.solver.constraints.Propagator<BoolVar>
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- org.chocosolver.sat.PropSat
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- All Implemented Interfaces:
Comparable<Propagator>
,ICause
,Identity
public class PropSat extends Propagator<BoolVar>
A propagator to deal with clauses and interface aSatSolver
.- Since:
- 12/07/13
- Author:
- Charles Prud'homme
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Field Summary
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Fields inherited from class org.chocosolver.solver.constraints.Propagator
ACTIVE, constraint, DEFAULT_EXPL, model, operations, OUTPUT_DEFAULT_EXPL, priority, reactToFineEvt, state, vars
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description boolean
addClause(gnu.trove.list.TIntList lits)
Add a clause to SAT solvervoid
addLearnt(int... lits)
Add learnt clause to SAT solvervoid
afterAddingClauses()
void
beforeAddingClauses()
int
getPropagationConditions(int vIdx)
Returns the specific mask indicating the variable events on which thisPropagator
object can react.
A mask is a bitwise OR operations overIEventType
this can react on.org.chocosolver.sat.SatSolver
getSatSolver()
void
initialize()
Initializes this propagatorESat
isEntailed()
Check wetherthis
is entailed according to the current state of its internal structure.int
makeLiteral(BoolVar expr, boolean sign)
Creates, or returns if already existing, the literal corresponding to :int
makeVar(BoolVar expr)
Creates, or returns if already existing, the literal corresponding to :void
propagate(int evtmask)
Call the main filtering algorithm to apply to theDomain
of theVariable
objects.void
propagate(int idxVarInProp, int mask)
Incremental filtering algorithm defined within thePropagator
, 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, 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
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Constructor Detail
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PropSat
public PropSat(Model model)
Create a (unique) propagator for clauses recording and propagation.- Parameters:
model
- the solver that declares the propagator
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Method Detail
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getPropagationConditions
public int getPropagationConditions(int vIdx)
Description copied from class:Propagator
Returns the specific mask indicating the variable events on which thisPropagator
object can react.
A mask is a bitwise OR operations overIEventType
this can react on. For example, consider a propagator that can deduce filtering based on the lower bound of the integer variable X. Then, for this variable, the mask should be equal to :int mask = IntEventType.INCLOW.getMask() | IntEventType.INSTANTIATE.getMask();
or, in a more convenient way:int mask = IntEvtType.combine(IntEventType.INCLOW,IntEventType.INSTANTIATE);
That indicates the following behavior:- if X is instantiated, this propagator will be executed,
- if the lower bound of X is modified, this propagator will be executed,
- if the lower bound of X is removed, the event is promoted from REMOVE to INCLOW and this propagator will NOT be executed,
- otherwise, this propagator will NOT be executed
IntEventType.VOID
which states that this propagator should not be aware of modifications applied to the variable in position vIdx.- Overrides:
getPropagationConditions
in classPropagator<BoolVar>
- Parameters:
vIdx
- index of the variable within the propagator- Returns:
- an int composed of
REMOVE
and/orINSTANTIATE
and/orDECUPP
and/orINCLOW
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propagate
public void propagate(int evtmask) throws ContradictionException
Description copied from class:Propagator
Call the main filtering algorithm to apply to theDomain
of theVariable
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 classPropagator<BoolVar>
- Parameters:
evtmask
- type of propagation eventthis
must consider.- Throws:
ContradictionException
- when a contradiction occurs, like domain wipe out or other incoherencies.
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propagate
public void propagate(int idxVarInProp, int mask) throws ContradictionException
Description copied from class:Propagator
Incremental filtering algorithm defined within thePropagator
, 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 totrue
in the constructor. Otherwise, it executespropagate(PropagatorEventType.CUSTOM_PROPAGATION.getStrengthenedMask());
- Overrides:
propagate
in classPropagator<BoolVar>
- Parameters:
idxVarInProp
- index of the variablevar
inthis
mask
- type of event- Throws:
ContradictionException
- if a contradiction occurs
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isEntailed
public ESat isEntailed()
Description copied from class:Propagator
Check wetherthis
is entailed according to the current state of its internal structure. At least, should check the satisfaction ofthis
(when all is instantiated).- Specified by:
isEntailed
in classPropagator<BoolVar>
- Returns:
- ESat.TRUE if entailed, ESat.FALSE if not entailed, ESat.UNDEFINED if unknown
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getSatSolver
public org.chocosolver.sat.SatSolver getSatSolver()
- Returns:
- the underlying SAT solver
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initialize
public void initialize()
Initializes this propagator
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makeVar
public int makeVar(BoolVar expr)
Creates, or returns if already existing, the literal corresponding to :expr
is trueThe negation of the literal is managed outside.
- Parameters:
expr
- a boolean variable- Returns:
- its literal
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makeLiteral
public int makeLiteral(BoolVar expr, boolean sign)
Creates, or returns if already existing, the literal corresponding to :expr
is trueThe negation of the literal is managed outside.
- Parameters:
expr
- a boolean variablesign
- true for even- Returns:
- its literal
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beforeAddingClauses
public void beforeAddingClauses()
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afterAddingClauses
public void afterAddingClauses()
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addClause
public boolean addClause(gnu.trove.list.TIntList lits)
Add a clause to SAT solver- Parameters:
lits
- clause- Returns:
- false if failure is detected
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addLearnt
public void addLearnt(int... lits)
Add learnt clause to SAT solver- Parameters:
lits
- clause
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