Search engine that connects to a generic SAT reasoning module. More...

#include <search_sat.h>

Inherits CVC3::SearchEngine.

Collaboration diagram for CVC3::SearchSat:

[legend]

List of all members.

Classes

class LitPriorityPair
Pair of Lit and priority of this Lit. More...
class Restorer

Public Member Functions

SearchSat (TheoryCore *core, const std::string &name)
virtual ~SearchSat ()
Destructor.
virtual const std::string & getName ()
Name of this search engine.
virtual void registerAtom (const Expr &e)
Register an atomic formula of interest.
virtual Theorem getImpliedLiteral ()
Return next literal implied by last assertion. Null Expr if none.
virtual void push ()
Push a checkpoint.
virtual void pop ()
Restore last checkpoint.
virtual QueryResult checkValid (const Expr &e, Theorem &result)
Checks the validity of a formula in the current context.
virtual QueryResult restart (const Expr &e, Theorem &result)
Reruns last check with e as an additional assumption.
virtual void returnFromCheck ()
Returns to context immediately before last call to checkValid.
virtual Theorem lastThm ()
Returns the result of the most recent valid theorem.
virtual Theorem newUserAssumption (const Expr &e)
Generate and add an assumption to the set of assumptions in the current context.
virtual void getUserAssumptions (std::vector< Expr > &assumptions)
Get all user assumptions made in this and all previous contexts.
virtual void getInternalAssumptions (std::vector< Expr > &assumptions)
Get assumptions made internally in this and all previous contexts.
virtual void getAssumptions (std::vector< Expr > &assumptions)
Get all assumptions made in this and all previous contexts.
virtual bool isAssumption (const Expr &e)
Check if the formula has already been assumed previously.
virtual void getCounterExample (std::vector< Expr > &assertions, bool inOrder=true)
Will return the set of assertions which make the queried formula false.
virtual Proof getProof ()
Returns the proof term for the last proven query.
virtual FormulaValue getValue (const CVC3::Expr &e)

Private Member Functions

void restorePre ()
Get rid of bottom scope entries in prioritySet.
void restore ()
Get rid of entries in prioritySet and pendingLemmas added since last push.
bool recordNewRootLit (SAT::Lit lit, int priority=0, bool atBottomScope=false)
Helper for addLemma and check.
void addLemma (const Theorem &thm, int priority=0, bool atBotomScope=false)
Core theory callback which adds a new lemma from the core theory.
int getBottomScope ()
Core theory callback which asks for the bottom scope for current query.
void addSplitter (const Expr &e, int priority)
Core theory callback which suggests a splitter.
void assertLit (SAT::Lit l)
DPLLT callback to inform theory that a literal has been assigned.
SAT::DPLLT::ConsistentResult checkConsistent (SAT::CNF_Formula &cnf, bool fullEffort)
DPLLT callback to ask if theory has detected inconsistency.
SAT::Lit getImplication ()
DPLLT callback to get theory propagations.
void getExplanation (SAT::Lit l, SAT::CNF_Formula &cnf)
DPLLT callback to explain a theory propagation.
bool getNewClauses (SAT::CNF_Formula &cnf)
DPLLT callback to get more general theory clauses.
SAT::Lit makeDecision ()
DPLLT callback to decide which literal to split on next.
bool findSplitterRec (SAT::Lit lit, SAT::Var::Val value, SAT::Lit *litDecision)
Recursively traverse DAG looking for a splitter.
SAT::Var::Val getValue (SAT::Lit c)
Get the value of a CNF Literal.
SAT::Var::Val getValue (SAT::Var v)
void setValue (SAT::Var v, SAT::Var::Val val)
Set the value of a variable.
bool checkJustified (SAT::Var v)
Check whether this variable's value is justified.
void setJustified (SAT::Var v)
Mark this variable as justified.
QueryResult check (const Expr &e, Theorem &result, bool isRestart=false)
Main checking procedure shared by checkValid and restart.
void newUserAssumptionIntHelper (const Theorem &thm, SAT::CNF_Formula_Impl &cnf, bool atBottomScope)
Helper for newUserAssumptionInt.
Theorem newUserAssumptionInt (const Expr &e, SAT::CNF_Formula_Impl &cnf, bool atBottomScope)
Helper for newUserAssumption.

Private Attributes

std::string d_name
Name of search engine.
CDO< int > d_bottomScope
Bottom scope for current query.
CDO< Expr > d_lastCheck
Last expr checked for validity.
CDO< Theorem > d_lastValid
Theorem from the last successful checkValid call. It is used by getProof and getAssumptions.
CDList< Theorem > d_userAssumptions
List of all user assumptions.
CDList< Theorem > d_intAssumptions
List of all internal assumptions.
CDO< unsigned > d_idxUserAssump
Index to where unprocessed assumptions start.
TheoryCore::CoreSatAPI * d_coreSatAPI
SAT::DPLLT * d_dpllt
Pointer to DPLLT implementation.
SAT::DPLLT::TheoryAPI * d_theoryAPI
Implementation of TheoryAPI for DPLLT.
SAT::DPLLT::Decider * d_decider
Implementation of Decider for DPLLT.
CDMap< Expr, Theorem > d_theorems
Store of theorems for expressions sent to DPLLT.
SAT::CNF_Manager * d_cnfManager
Manages CNF formula and its relationship to original Exprs and Theorems.
SAT::CNF_Manager::CNFCallback * d_cnfCallback
Callback for CNF_Manager.
std::vector< SAT::Var::Val > d_vars
Cached values of variables.
bool d_inCheckSat
Whether we are currently in a call to dpllt->checkSat.
SAT::CD_CNF_Formula d_lemmas
CNF Formula used for theory lemmas.
std::vector< std::pair
< Theorem, int > > d_pendingLemmas
Lemmas waiting to be translated since last call to getNewClauses()
std::vector< bool > d_pendingScopes
Scope parameter for lemmas waiting to be translated since last call to getNewClauses()
CDO< unsigned > d_pendingLemmasSize
Backtracking size of d_pendingLemmas.
CDO< unsigned > d_pendingLemmasNext
Backtracking next item in d_pendingLemmas.
CDO< unsigned > d_lemmasNext
Current position in d_lemmas.
std::vector< unsigned > d_varsUndoList
List for backtracking var values.
CDO< unsigned > d_varsUndoListSize
Backtracking size of d_varsUndoList.
std::set< LitPriorityPair > d_prioritySet
Used to determine order to find splitters.
CDO< std::set< LitPriorityPair >
::const_iterator > d_prioritySetStart
Current position in prioritySet.
CDO< unsigned > d_prioritySetEntriesSize
Backtracking size of priority set entries.
std::vector< std::set
< LitPriorityPair >::iterator > d_prioritySetEntries
Entries in priority set in insertion order (so set can be backtracked)
std::vector< unsigned > d_prioritySetBottomEntriesSizeStack
Backtracking size of priority set entries at bottom scope.
unsigned d_prioritySetBottomEntriesSize
Current size of bottom entries.
std::vector< std::set
< LitPriorityPair >::iterator > d_prioritySetBottomEntries
Entries in priority set in insertion order (so set can be backtracked)
CDO< unsigned > d_lastRegisteredVar
Last Var registered with core theory.
CDO< bool > d_dplltReady
Whether it's OK to call DPLLT solver from the current scope.
CDO< unsigned > d_nextImpliedLiteral
Restorer d_restorer
Instance of Restorer class.

Friends

class Restorer
Helper class for resetting DPLLT engine.
class SearchSatCoreSatAPI
class SearchSatCNFCallback
class SearchSatTheoryAPI
class SearchSatDecider

Detailed Description

Search engine that connects to a generic SAT reasoning module.

Definition at line 40 of file search_sat.h.

Constructor & Destructor Documentation

SearchSat::SearchSat	(	TheoryCore *	core,
		const std::string &	name
	)

Constructor name is the name of the dpllt engine to use, as returned by getName()

Definition at line 936 of file search_sat.cpp.

References d_cnfCallback, d_cnfManager, d_coreSatAPI, d_decider, d_dpllt, d_prioritySet, d_prioritySetStart, d_theoryAPI, CVC3::TheoryCore::getCM(), CVC3::TheoryCore::getFlags(), CVC3::TheoryCore::getStatistics(), CVC3::TheoryCore::getTM(), SAT::CNF_Manager::registerCNFCallback(), CVC3::TheoryCore::registerCoreSatAPI(), SearchSatCNFCallback, SearchSatCoreSatAPI, SearchSatDecider, SearchSatTheoryAPI, and CVC3::TheoremManager::withProof().

SearchSat::~SearchSat ( ) [virtual]

Destructor.

Definition at line 991 of file search_sat.cpp.

References d_cnfCallback, d_cnfManager, d_coreSatAPI, d_decider, d_dpllt, and d_theoryAPI.

Member Function Documentation

void SearchSat::restorePre ( ) [private]

Get rid of bottom scope entries in prioritySet.

Definition at line 115 of file search_sat.cpp.

References DebugAssert.

Referenced by CVC3::SearchSat::Restorer::notifyPre().

void SearchSat::restore ( void ) [private]

Get rid of entries in prioritySet and pendingLemmas added since last push.

Definition at line 129 of file search_sat.cpp.

References UNKNOWN.

Referenced by CVC3::SearchSat::Restorer::notify().

bool SearchSat::recordNewRootLit	(	SAT::Lit	lit,
		int	priority = `0`,
		bool	atBottomScope = `false`
	)		`[private]`

Helper for addLemma and check.

Definition at line 146 of file search_sat.cpp.

References DebugAssert.

Referenced by newUserAssumptionIntHelper().

void SearchSat::addLemma	(	const Theorem &	thm,
		int	priority = `0`,
		bool	atBotomScope = `false`
	)		`[private]`

Core theory callback which adds a new lemma from the core theory.

Definition at line 170 of file search_sat.cpp.

References DebugAssert, CVC3::Theorem::getExpr(), IF_DEBUG, CVC3::PRESENTATION_LANG, CVC3::Expr::toString(), and TRACE.

int CVC3::SearchSat::getBottomScope ( ) [inline, private]

Core theory callback which asks for the bottom scope for current query.

Definition at line 184 of file search_sat.h.

References d_bottomScope.

void SearchSat::addSplitter	(	const Expr &	e,
		int	priority
	)		`[private]`

Core theory callback which suggests a splitter.

Definition at line 186 of file search_sat.cpp.

References DebugAssert, and CVC3::Expr::isEq().

void SearchSat::assertLit ( SAT::Lit l ) [private]

DPLLT callback to inform theory that a literal has been assigned.

Definition at line 193 of file search_sat.cpp.

References DebugAssert, CVC3::FALSE_VAL, SAT::Lit::getVar(), IF_DEBUG, CVC3::Expr::isAbsLiteral(), CVC3::Expr::isIntAssumption(), CVC3::Expr::isNot(), CVC3::Expr::isNull(), SAT::Lit::isPositive(), CVC3::Expr::setIntAssumption(), CVC3::Theorem::setQuantLevel(), CVC3::Expr::toString(), TRACE, CVC3::TRUE_VAL, and UNKNOWN.

SAT::DPLLT::ConsistentResult SearchSat::checkConsistent	(	SAT::CNF_Formula &	cnf,
		bool	fullEffort
	)		`[private]`

DPLLT callback to ask if theory has detected inconsistency.

Definition at line 258 of file search_sat.cpp.

References DebugAssert, and UNKNOWN.

Lit SearchSat::getImplication ( ) [private]

DPLLT callback to get theory propagations.

Definition at line 284 of file search_sat.cpp.

References DebugAssert, CVC3::Theorem::getExpr(), SAT::Lit::isNull(), CVC3::Theorem::isNull(), CVC3::Expr::isUserRegisteredAtom(), SAT::Lit::reset(), CVC3::TRUE_VAL, and CVC3::Expr::unnegate().

void SearchSat::getExplanation	(	SAT::Lit	l,
		SAT::CNF_Formula &	cnf
	)		`[private]`

DPLLT callback to explain a theory propagation.

Definition at line 304 of file search_sat.cpp.

References DebugAssert, SAT::CNF_Formula::empty(), CVC3::CDMap< Key, Data, HashFcn >::end(), CVC3::CDMap< Key, Data, HashFcn >::find(), and UNKNOWN.

bool SearchSat::getNewClauses ( SAT::CNF_Formula & cnf ) [private]

DPLLT callback to get more general theory clauses.

Definition at line 318 of file search_sat.cpp.

References DebugAssert, and UNKNOWN.

Lit SearchSat::makeDecision ( ) [private]

DPLLT callback to decide which literal to split on next.

Definition at line 346 of file search_sat.cpp.

References DebugAssert.

bool SearchSat::findSplitterRec	(	SAT::Lit	lit,
		SAT::Var::Val	value,
		SAT::Lit *	litDecision
	)		`[private]`

Recursively traverse DAG looking for a splitter.

Returns true if a splitter is found, false otherwise. The splitter is returned in lit (lit should be set to true). Nodes whose current value is fully justified are marked by calling setFlag to avoid searching them in the future.

Definition at line 364 of file search_sat.cpp.

References AND, DebugAssert, std::endl(), CVC3::FALSE_VAL, FatalAssert, SAT::Lit::getVar(), IFF, IMPLIES, SAT::Lit::isFalse(), SAT::Lit::isInverted(), SAT::Lit::isTrue(), SAT::Lit::isVar(), ITE, OR, CVC3::TRUE_VAL, UNKNOWN, and XOR.

SAT::Var::Val CVC3::SearchSat::getValue ( SAT::Lit c ) [inline, private]

Get the value of a CNF Literal.

Definition at line 214 of file search_sat.h.

References d_vars, DebugAssert, CVC3::FALSE_VAL, SAT::Lit::getVar(), SAT::Var::invertValue(), SAT::Lit::isInverted(), SAT::Lit::isNull(), SAT::Lit::isPositive(), SAT::Lit::isTrue(), SAT::Lit::isVar(), and SAT::Var::TRUE_VAL.

Referenced by getValue().

SAT::Var::Val CVC3::SearchSat::getValue ( SAT::Var v ) [inline, private]

Definition at line 223 of file search_sat.h.

References d_vars, DebugAssert, and SAT::Var::isVar().

void CVC3::SearchSat::setValue	(	SAT::Var	v,
		SAT::Var::Val	val
	)		`[inline, private]`

Set the value of a variable.

Definition at line 229 of file search_sat.h.

References d_vars, d_varsUndoList, d_varsUndoListSize, DebugAssert, SAT::Var::isNull(), and SAT::Var::UNKNOWN.

bool CVC3::SearchSat::checkJustified ( SAT::Var v ) [inline, private]

Check whether this variable's value is justified.

Definition at line 241 of file search_sat.h.

References SAT::CNF_Manager::concreteLit(), d_cnfManager, and CVC3::Expr::isJustified().

void CVC3::SearchSat::setJustified ( SAT::Var v ) [inline, private]

Mark this variable as justified.

Definition at line 245 of file search_sat.h.

References SAT::CNF_Manager::concreteLit(), d_cnfManager, and CVC3::Expr::setJustified().

QueryResult SearchSat::check	(	const Expr &	e,
		Theorem &	result,
		bool	isRestart = `false`
	)		`[private]`

Main checking procedure shared by checkValid and restart.

Definition at line 638 of file search_sat.cpp.

References DebugAssert, std::endl(), FORALL, CVC3::Expr::getType(), SAT::Lit::getVar(), CVC3::INVALID, CVC3::Type::isBool(), CVC3::Expr::isEq(), CVC3::Expr::isExists(), CVC3::Expr::isFalse(), CVC3::Expr::isForall(), CVC3::Expr::isNot(), SAT::Lit::isPositive(), CVC3::Expr::isTrue(), CVC3::pop(), CVC3::push(), SATISFIABLE, CVC3::CDList< T >::size(), CVC3::Type::toString(), CVC3::Expr::toString(), TRACE, UNKNOWN, UNSATISFIABLE, and CVC3::VALID.

Referenced by checkValid(), and restart().

void SearchSat::newUserAssumptionIntHelper	(	const Theorem &	thm,
		SAT::CNF_Formula_Impl &	cnf,
		bool	atBottomScope
	)		`[private]`

Helper for newUserAssumptionInt.

Definition at line 1042 of file search_sat.cpp.

References SAT::CNF_Manager::addAssumption(), CVC3::CommonProofRules::andElim(), CVC3::Expr::arity(), d_cnfManager, CVC3::SearchEngine::d_commonRules, CVC3::SearchEngine::d_core, SAT::CNF_Formula_Impl::deleteLast(), CVC3::Theorem::getExpr(), CVC3::TheoryCore::getFlags(), CVC3::Expr::isAnd(), and recordNewRootLit().

Referenced by newUserAssumptionInt().

Theorem SearchSat::newUserAssumptionInt	(	const Expr &	e,
		SAT::CNF_Formula_Impl &	cnf,
		bool	atBottomScope
	)		`[private]`

virtual const std::string& CVC3::SearchSat::getName ( ) [inline, virtual]

Name of this search engine.

Implements CVC3::SearchEngine.

Definition at line 268 of file search_sat.h.

References d_name.

void SearchSat::registerAtom ( const Expr & e ) [virtual]

Register an atomic formula of interest.

Registered atoms are tracked by the decision procedures. If one of them is deduced to be true or false, it is added to a list of implied literals. Implied literals can be retrieved with the getImpliedLiteral function

Implements CVC3::SearchEngine.

Definition at line 1002 of file search_sat.cpp.

References CVC3::SearchEngine::d_core, CVC3::Expr::isRegisteredAtom(), CVC3::TheoryCore::registerAtom(), and CVC3::Expr::setUserRegisteredAtom().

Theorem SearchSat::getImpliedLiteral ( ) [virtual]

Return next literal implied by last assertion. Null Expr if none.

Returned literals are either registered atomic formulas or their negation

Implements CVC3::SearchEngine.

Definition at line 1010 of file search_sat.cpp.

References CVC3::SearchEngine::d_core, d_nextImpliedLiteral, CVC3::Theorem::getExpr(), CVC3::TheoryCore::getImpliedLiteralByIndex(), CVC3::Expr::isUserRegisteredAtom(), and CVC3::Expr::unnegate().

virtual void CVC3::SearchSat::push ( ) [inline, virtual]

Push a checkpoint.

Implements CVC3::SearchEngine.

Definition at line 271 of file search_sat.h.

References d_dpllt, and SAT::DPLLT::push().

virtual void CVC3::SearchSat::pop ( ) [inline, virtual]

Restore last checkpoint.

Implements CVC3::SearchEngine.

Definition at line 272 of file search_sat.h.

References d_dpllt, and SAT::DPLLT::pop().

Referenced by returnFromCheck().

virtual QueryResult CVC3::SearchSat::checkValid	(	const Expr &	e,
		Theorem &	result
	)		`[inline, virtual]`

Checks the validity of a formula in the current context.

If the query is valid, it returns VALID, the result parameter contains the corresponding theorem, and the scope and context are the same as when called. If it returns INVALID, the context will be one which falsifies the query. If it returns UNKNOWN, the context will falsify the query, but the context may be inconsistent. Finally, if it returns ABORT, the context will be one which satisfies as much as possible.

Parameters:

e	the formula to check.
result	the resulting theorem, if the formula is valid.

Implements CVC3::SearchEngine.

Definition at line 273 of file search_sat.h.

References check().

virtual QueryResult CVC3::SearchSat::restart	(	const Expr &	e,
		Theorem &	result
	)		`[inline, virtual]`

Reruns last check with e as an additional assumption.

This method should only be called after a query which is invalid.

Parameters:

e	the additional assumption
result	the resulting theorem, if the query is valid.

Implements CVC3::SearchEngine.

Definition at line 275 of file search_sat.h.

References check().

void SearchSat::returnFromCheck ( ) [virtual]

Returns to context immediately before last call to checkValid.

This method should only be called after a query which returns something other than VALID.

Implements CVC3::SearchEngine.

Definition at line 1022 of file search_sat.cpp.

References d_bottomScope, and pop().

virtual Theorem CVC3::SearchSat::lastThm ( ) [inline, virtual]

Returns the result of the most recent valid theorem.

Returns Null Theorem if last call was not valid

Implements CVC3::SearchEngine.

Definition at line 278 of file search_sat.h.

References d_lastValid.

Theorem SearchSat::newUserAssumption ( const Expr & e ) [virtual]

Generate and add an assumption to the set of assumptions in the current context.

By default, the assumption is added at the current scope. The default can be overridden by specifying the scope parameter.

Implements CVC3::SearchEngine.

Definition at line 1102 of file search_sat.cpp.

References SAT::DPLLT::addAssertion(), d_dpllt, and newUserAssumptionInt().

void SearchSat::getUserAssumptions ( std::vector< Expr > & assumptions ) [virtual]

Get all user assumptions made in this and all previous contexts.

User assumptions are created either by calls to newUserAssumption or a call to checkValid. In the latter case, the negated query is added as an assumption.

Parameters:

assumptions should be empty on entry.

Implements CVC3::SearchEngine.

Definition at line 1111 of file search_sat.cpp.

References CVC3::CDList< T >::begin(), d_userAssumptions, and CVC3::CDList< T >::end().

void SearchSat::getInternalAssumptions ( std::vector< Expr > & assumptions ) [virtual]

Get assumptions made internally in this and all previous contexts.

Internal assumptions are literals assumed by the sat solver.

Parameters:

assumptions should be empty on entry.

Implements CVC3::SearchEngine.

Definition at line 1119 of file search_sat.cpp.

References CVC3::CDList< T >::begin(), d_intAssumptions, and CVC3::CDList< T >::end().

Referenced by getCounterExample().

void SearchSat::getAssumptions ( std::vector< Expr > & assumptions ) [virtual]

Get all assumptions made in this and all previous contexts.

Parameters:

assumptions should be an empty vector which will be filled \ with the assumptions

Implements CVC3::SearchEngine.

Definition at line 1128 of file search_sat.cpp.

References CVC3::CDList< T >::begin(), d_intAssumptions, d_userAssumptions, CVC3::CDList< T >::end(), and CVC3::Expr::isUserAssumption().

bool SearchSat::isAssumption ( const Expr & e ) [virtual]

Check if the formula has already been assumed previously.

Implements CVC3::SearchEngine.

Definition at line 1163 of file search_sat.cpp.

References CVC3::Expr::isIntAssumption(), and CVC3::Expr::isUserAssumption().

Referenced by newUserAssumptionInt().

void SearchSat::getCounterExample	(	std::vector< Expr > &	assertions,
		bool	inOrder = `true`
	)		`[virtual]`

Will return the set of assertions which make the queried formula false.

This method should only be called after an query which returns INVALID. It will try to return the simplest possible set of assertions which are sufficient to make the queried expression false.

Parameters:

assertions	should be empty on entry.
inOrder	if true, returns the assertions in the order they were asserted. This is slightly more expensive than inOrder = false.

Implements CVC3::SearchEngine.

Definition at line 1169 of file search_sat.cpp.

References d_lastValid, CVC3::CDO< T >::get(), getInternalAssumptions(), and CVC3::Theorem::isNull().

Proof SearchSat::getProof ( ) [virtual]

Returns the proof term for the last proven query.

It should be called only after a query which returns VALID. In any other case, it returns Null.

Implements CVC3::SearchEngine.

Definition at line 1178 of file search_sat.cpp.

References CVC3::SearchEngine::d_core, d_lastValid, CVC3::CDO< T >::get(), CVC3::Theorem::getProof(), CVC3::TheoryCore::getTM(), CVC3::Theorem::isNull(), and CVC3::TheoremManager::withProof().

virtual FormulaValue CVC3::SearchSat::getValue ( const CVC3::Expr & e ) [inline, virtual]

Implements CVC3::SearchEngine.

Definition at line 289 of file search_sat.h.

References d_cnfManager, DebugAssert, std::endl(), CVC3::FALSE_VAL, SAT::Var::FALSE_VAL, FatalAssert, SAT::CNF_Manager::getCNFLit(), getValue(), SAT::Lit::isNull(), CVC3::Expr::toString(), CVC3::TRUE_VAL, SAT::Var::TRUE_VAL, SAT::Var::UNKNOWN, and CVC3::UNKNOWN_VAL.

Friends And Related Function Documentation

friend class Restorer [friend]

Helper class for resetting DPLLT engine.

We need to be notified when the scope goes below the scope from which the last invalid call to checkValid originated. This helper class ensures that this happens.

Definition at line 158 of file search_sat.h.

friend class SearchSatCoreSatAPI [friend]

Definition at line 179 of file search_sat.h.

Referenced by SearchSat().

friend class SearchSatCNFCallback [friend]

Definition at line 180 of file search_sat.h.

Referenced by SearchSat().

friend class SearchSatTheoryAPI [friend]

Definition at line 188 of file search_sat.h.

Referenced by SearchSat().

friend class SearchSatDecider [friend]

Definition at line 200 of file search_sat.h.