public final class PropEqualX_Y extends Propagator<IntVar>
Ensures Arc-Consistency
ACTIVE, constraint, DEFAULT_EXPL, model, operations, OUTPUT_DEFAULT_EXPL, priority, reactToFineEvt, state, vars
Constructor and Description |
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PropEqualX_Y(IntVar x,
IntVar y) |
Modifier and Type | Method and Description |
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void |
explain(ExplanationForSignedClause explanation,
ValueSortedMap<IntVar> front,
Implications ig,
int p)
Clausal explanation for this cause.
|
int |
getPropagationConditions(int vIdx)
Returns the specific mask indicating the variable events on which this
Propagator object can react.A mask is a bitwise OR operations over IEventType this can react on. |
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 varIdx,
int mask)
Incremental filtering algorithm defined within the
Propagator , called whenever the variable
of index idxVarInProp has changed. |
String |
toString() |
addVariable, arity, compareTo, defaultExplain, doFinePropagation, doFlush, doSchedule, doScheduleEvent, dynPriority, equals, 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, unlinkVariables, unschedule
public int getPropagationConditions(int vIdx)
Propagator
Propagator
object can react.IEventType
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:
IntEventType.VOID
which states
that this propagator should not be aware of modifications applied to the variable in position vIdx.getPropagationConditions
in class Propagator<IntVar>
vIdx
- index of the variable within the propagatorREMOVE
and/or INSTANTIATE
and/or DECUPP
and/or INCLOW
public void propagate(int evtmask) throws ContradictionException
Propagator
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:
propagate
in class Propagator<IntVar>
evtmask
- type of propagation event this
must consider.ContradictionException
- when a contradiction occurs, like domain wipe out or other incoherencies.public void propagate(int varIdx, int mask) throws ContradictionException
Propagator
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());
propagate
in class Propagator<IntVar>
varIdx
- index of the variable var
in this
mask
- type of eventContradictionException
- if a contradiction occurspublic ESat isEntailed()
Propagator
this
is entailed according to the current state of its internal structure.
At least, should check the satisfaction of this
(when all is instantiated).isEntailed
in class Propagator<IntVar>
public void explain(ExplanationForSignedClause explanation, ValueSortedMap<IntVar> front, Implications ig, int p)
ICause
This method must filled explanations with inferred literals. These literals are inferred from the analysis of (a subset of) conflicting nodes stored in front, the implication graph ig and the current node in conflict, not yet contained in front.
Optionally, this method can update front by looking for a predecessor of any node that seems more relevant than the declared one.
explain
in interface ICause
explain
in class Propagator<IntVar>
explanation
- explanation to computefront
- ordered map of (variable,node> in the conflict frontier of the implication graph.ig
- an implication graphp
- the pivot node out of frontpublic String toString()
toString
in class Propagator<IntVar>
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