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/********************* */
/*! \file cnf_proof.h
** \verbatim
** Top contributors (to current version):
** Liana Hadarean, Guy Katz, Alex Ozdemir
** This file is part of the CVC4 project.
** Copyright (c) 2009-2019 by the authors listed in the file AUTHORS
** in the top-level source directory) and their institutional affiliations.
** All rights reserved. See the file COPYING in the top-level source
** directory for licensing information.\endverbatim
**
** \brief A manager for CnfProofs.
**
** A manager for CnfProofs.
**
**
**/
#include "cvc4_private.h"
#ifndef CVC4__CNF_PROOF_H
#define CVC4__CNF_PROOF_H
#include <iosfwd>
#include <unordered_map>
#include <unordered_set>
#include "context/cdhashmap.h"
#include "proof/clause_id.h"
#include "proof/lemma_proof.h"
#include "proof/sat_proof.h"
#include "util/maybe.h"
#include "util/proof.h"
namespace CVC4 {
namespace prop {
class CnfStream;
}/* CVC4::prop namespace */
class CnfProof;
typedef std::unordered_map<prop::SatVariable, Expr> SatVarToExpr;
typedef std::unordered_map<Node, Node, NodeHashFunction> NodeToNode;
typedef std::unordered_set<ClauseId> ClauseIdSet;
typedef context::CDHashMap<ClauseId, Node> ClauseIdToNode;
typedef context::CDHashMap<Node, ProofRule, NodeHashFunction> NodeToProofRule;
typedef std::map<std::set<Node>, LemmaProofRecipe> LemmaToRecipe;
typedef std::pair<Node, Node> NodePair;
typedef std::set<NodePair> NodePairSet;
class CnfProof {
protected:
CVC4::prop::CnfStream* d_cnfStream;
/** Map from ClauseId to the assertion that lead to adding this clause **/
ClauseIdToNode d_clauseToAssertion;
/** Map from assertion to reason for adding assertion **/
NodeToProofRule d_assertionToProofRule;
/** Map from lemma to the recipe for proving it **/
LemmaToRecipe d_lemmaToProofRecipe;
/** Top of stack is assertion currently being converted to CNF **/
std::vector<Node> d_currentAssertionStack;
/** Top of stack is top-level fact currently being converted to CNF **/
std::vector<Node> d_currentDefinitionStack;
/** Map from ClauseId to the top-level fact that lead to adding this clause **/
ClauseIdToNode d_clauseToDefinition;
/** Top-level facts that follow from assertions during convertAndAssert **/
NodeSet d_definitions;
/** Map from top-level fact to facts/assertion that it follows from **/
NodeToNode d_cnfDeps;
ClauseIdSet d_explanations;
// The clause ID of the unit clause defining the true SAT literal.
ClauseId d_trueUnitClause;
// The clause ID of the unit clause defining the false SAT literal.
ClauseId d_falseUnitClause;
bool isDefinition(Node node);
Node getDefinitionForClause(ClauseId clause);
std::string d_name;
public:
CnfProof(CVC4::prop::CnfStream* cnfStream,
context::Context* ctx,
const std::string& name);
Node getAtom(prop::SatVariable var);
prop::SatLiteral getLiteral(TNode node);
bool hasLiteral(TNode node);
void ensureLiteral(TNode node, bool noPreregistration = false);
void collectAtoms(const prop::SatClause* clause,
std::set<Node>& atoms);
void collectAtomsForClauses(const IdToSatClause& clauses,
std::set<Node>& atoms);
void collectAtomsAndRewritesForLemmas(const IdToSatClause& lemmaClauses,
std::set<Node>& atoms,
NodePairSet& rewrites);
void collectAssertionsForClauses(const IdToSatClause& clauses,
NodeSet& assertions);
/** Methods for logging what the CnfStream does **/
// map the clause back to the current assertion where it came from
// if it is an explanation, it does not have a CNF proof since it is
// already in CNF
void registerConvertedClause(ClauseId clause, bool explanation=false);
// The CNF proof has a special relationship to true and false.
// In particular, it need to know the identity of clauses defining
// canonical true and false literals in the underlying SAT solver.
void registerTrueUnitClause(ClauseId clauseId);
void registerFalseUnitClause(ClauseId clauseId);
inline ClauseId getTrueUnitClause() { return d_trueUnitClause; };
inline ClauseId getFalseUnitClause() { return d_falseUnitClause; };
/** Clause is one of the clauses defining the node expression*/
void setClauseDefinition(ClauseId clause, Node node);
/** Clause is one of the clauses defining top-level assertion node*/
void setClauseAssertion(ClauseId clause, Node node);
void registerAssertion(Node assertion, ProofRule reason);
void setCnfDependence(Node from, Node to);
void pushCurrentAssertion(Node assertion); // the current assertion being converted
void popCurrentAssertion();
Node getCurrentAssertion();
void pushCurrentDefinition(Node assertion); // the current Tseitin definition being converted
void popCurrentDefinition();
Node getCurrentDefinition();
/**
* Checks whether the assertion stack is empty.
*/
bool isAssertionStackEmpty() const { return d_currentAssertionStack.empty(); }
void setProofRecipe(LemmaProofRecipe* proofRecipe);
LemmaProofRecipe getProofRecipe(const std::set<Node> &lemma);
bool haveProofRecipe(const std::set<Node> &lemma);
// accessors for the leaf assertions that are being converted to CNF
bool isAssertion(Node node);
ProofRule getProofRule(Node assertion);
ProofRule getProofRule(ClauseId clause);
Node getAssertionForClause(ClauseId clause);
/** Virtual methods for printing things **/
virtual void printAtomMapping(const std::set<Node>& atoms,
std::ostream& os,
std::ostream& paren) = 0;
virtual void printAtomMapping(const std::set<Node>& atoms,
std::ostream& os,
std::ostream& paren,
ProofLetMap &letMap) = 0;
// Detects whether a clause has x v ~x for some x
// If so, returns the positive occurence's idx first, then the negative's
static Maybe<std::pair<size_t, size_t>> detectTrivialTautology(
const prop::SatClause& clause);
virtual void printClause(const prop::SatClause& clause,
std::ostream& os,
std::ostream& paren) = 0;
virtual void printCnfProofForClause(ClauseId id,
const prop::SatClause* clause,
std::ostream& os,
std::ostream& paren) = 0;
virtual ~CnfProof();
};/* class CnfProof */
class LFSCCnfProof : public CnfProof {
Node clauseToNode( const prop::SatClause& clause,
std::map<Node, unsigned>& childIndex,
std::map<Node, bool>& childPol );
bool printProofTopLevel(Node e, std::ostream& out);
public:
LFSCCnfProof(CVC4::prop::CnfStream* cnfStream,
context::Context* ctx,
const std::string& name)
: CnfProof(cnfStream, ctx, name)
{}
~LFSCCnfProof() {}
void printAtomMapping(const std::set<Node>& atoms,
std::ostream& os,
std::ostream& paren) override;
void printAtomMapping(const std::set<Node>& atoms,
std::ostream& os,
std::ostream& paren,
ProofLetMap& letMap) override;
void printClause(const prop::SatClause& clause,
std::ostream& os,
std::ostream& paren) override;
void printCnfProofForClause(ClauseId id,
const prop::SatClause* clause,
std::ostream& os,
std::ostream& paren) override;
};/* class LFSCCnfProof */
} /* CVC4 namespace */
#endif /* CVC4__CNF_PROOF_H */
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