Package org.sosy_lab.java_smt.basicimpl

Class AbstractUserPropagator

java.lang.Object

org.sosy_lab.java_smt.basicimpl.AbstractUserPropagator

All Implemented Interfaces:

UserPropagator

Direct Known Subclasses:

NQueensEnumeratingPropagator

public abstract class AbstractUserPropagator
extends Object
implements UserPropagator

Constructor Summary

Constructors

Constructor	Description
AbstractUserPropagator()

Method Summary

Modifier and Type	Method	Description
protected PropagatorBackend	getBackend()
void	initializeWithBackend(PropagatorBackend pBackend)	This method is invoked after the user propagator is registered via BasicProverEnvironment.registerUserPropagator(UserPropagator).
void	onDecision(BooleanFormula expr, boolean value)	This callback is invoked if the solver decides to branch on a registered expression.
void	onFinalCheck()	This callback is invoked when the solver finds a complete satisfying assignment.
void	onKnownValue(BooleanFormula expr, boolean value)	This callback is invoked if the solver gets to know the value of a registered expression (UserPropagator.registerExpression(org.sosy_lab.java_smt.api.BooleanFormula)).
void	onPop(int numPoppedLevels)	This callback is invoked when the solver backtracks.
void	onPush()	This callback is invoked whenever the solver creates a new decision level.
void	registerExpression(BooleanFormula theoryExpr)	Registers an expression to be observed by the UserPropagator.

Methods inherited from class java.lang.Object

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

Constructor Details

AbstractUserPropagator

public AbstractUserPropagator()

Method Details

getBackend

protected PropagatorBackend getBackend()

onPush

public void onPush()

Description copied from interface: UserPropagator

This callback is invoked whenever the solver creates a new decision level. A user propagator should maintain backtracking points on each push to enable later backtracking.

The onPush or onPop operation refers to internal state of the SMT/SAT solver while running a SAT check. This does not relate to Prover operations in the SMT-based API, such as BasicProverEnvironment.push(org.sosy_lab.java_smt.api.BooleanFormula) or BasicProverEnvironment.pop().

Specified by:

onPush in interface UserPropagator

onPop

public void onPop(int numPoppedLevels)

Description copied from interface: UserPropagator

This callback is invoked when the solver backtracks. The solver can backtrack multiple levels simultaneously.

The onPush or onPop operation refers to internal state of the SMT/SAT solver while running a SAT check. This does not relate to Prover operations in the SMT-based API, such as BasicProverEnvironment.push(org.sosy_lab.java_smt.api.BooleanFormula) or BasicProverEnvironment.pop().

Specified by:

onPop in interface UserPropagator

Parameters:

numPoppedLevels - The number of levels to backtrack (~ number of pushes to backtrack).

onFinalCheck

public void onFinalCheck()

Description copied from interface: UserPropagator

This callback is invoked when the solver finds a complete satisfying assignment. The user can check the found model for consistency and potentially raise conflicts via PropagatorBackend.propagateConflict(BooleanFormula[]).

Note: This callback is only invoked if the user propagator enabled it via PropagatorBackend.notifyOnFinalCheck().

Specified by:

onFinalCheck in interface UserPropagator

onKnownValue

public void onKnownValue(BooleanFormula expr,
 boolean value)

Description copied from interface: UserPropagator

This callback is invoked if the solver gets to know the value of a registered expression (UserPropagator.registerExpression(org.sosy_lab.java_smt.api.BooleanFormula)). Within the callback, the user can raise conflicts via PropagatorBackend.propagateConflict(org.sosy_lab.java_smt.api.BooleanFormula[]), propagate consequences via PropagatorBackend.propagateConsequence(org.sosy_lab.java_smt.api.BooleanFormula[], org.sosy_lab.java_smt.api.BooleanFormula), or influence the solvers decision heuristics via PropagatorBackend.propagateNextDecision(org.sosy_lab.java_smt.api.BooleanFormula, java.util.Optional<java.lang.Boolean>).

The reported value is only known on the current and later push levels, but will get invalidated when backtracking.

Note: This callback is only invoked if the user propagator enabled it via PropagatorBackend.notifyOnKnownValue().

Specified by:

onKnownValue in interface UserPropagator

Parameters:

expr - The expressions whose value is known.

value - The value of the expression.

onDecision

public void onDecision(BooleanFormula expr,
 boolean value)

Description copied from interface: UserPropagator

This callback is invoked if the solver decides to branch on a registered expression. (UserPropagator.registerExpression(org.sosy_lab.java_smt.api.BooleanFormula)). Within the callback, the user can change the decision by calling PropagatorBackend.propagateNextDecision(org.sosy_lab.java_smt.api.BooleanFormula, java.util.Optional<java.lang.Boolean>).

Note: This callback is only invoked if the user propagator enabled it via PropagatorBackend.notifyOnDecision().

Specified by:

onDecision in interface UserPropagator

Parameters:

expr - The expressions whose value gets decided (usually a literal).

value - The decision value.

initializeWithBackend

public void initializeWithBackend(PropagatorBackend pBackend)

Description copied from interface: UserPropagator

This method is invoked after the user propagator is registered via BasicProverEnvironment.registerUserPropagator(UserPropagator). The user can enable notifications by accessing the provided PropagatorBackend.

Warning: During its lifetime, a user propagator shall only be registered once via BasicProverEnvironment.registerUserPropagator(UserPropagator) for otherwise unexpected errors can occur. Implementations are advised to throw exceptions if this method is called multiple times.

Specified by:

initializeWithBackend in interface UserPropagator

registerExpression

public void registerExpression(BooleanFormula theoryExpr)

Description copied from interface: UserPropagator

Registers an expression to be observed by the UserPropagator. Solver actions related to the expression are reported:

• The callback UserPropagator.onKnownValue(org.sosy_lab.java_smt.api.BooleanFormula, boolean) gets invoked if the value of a registered expression becomes known (if notification was enabled via PropagatorBackend.notifyOnKnownValue()).
• The callback UserPropagator.onDecision(org.sosy_lab.java_smt.api.BooleanFormula, boolean) gets invoked right before the solver decides on the value of a registered expression (if notification was enabled via PropagatorBackend.notifyOnDecision()).

Specified by:

registerExpression in interface UserPropagator

Parameters:

theoryExpr - The expression to observe.