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/********************* */
/*! \file sat_solver.h
** \verbatim
** Top contributors (to current version):
** Dejan Jovanovic, Liana Hadarean, Morgan Deters
** 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 SAT Solver.
**
** SAT Solver.
**/
#include "cvc4_private.h"
#ifndef CVC4__PROP__SAT_SOLVER_H
#define CVC4__PROP__SAT_SOLVER_H
#include <stdint.h>
#include <string>
#include "context/cdlist.h"
#include "context/context.h"
#include "expr/node.h"
#include "proof/clause_id.h"
#include "prop/sat_solver_types.h"
#include "prop/bv_sat_solver_notify.h"
#include "util/statistics_registry.h"
namespace CVC4 {
namespace proof {
class ClausalBitVectorProof;
class ResolutionBitVectorProof;
} // namespace proof
namespace prop {
class TheoryProxy;
class SatSolver {
public:
/** Virtual destructor */
virtual ~SatSolver() { }
/** Assert a clause in the solver. */
virtual ClauseId addClause(SatClause& clause,
bool removable) = 0;
/** Return true if the solver supports native xor resoning */
virtual bool nativeXor() { return false; }
/** Add a clause corresponding to rhs = l1 xor .. xor ln */
virtual ClauseId addXorClause(SatClause& clause, bool rhs, bool removable) = 0;
/**
* Create a new boolean variable in the solver.
* @param isTheoryAtom is this a theory atom that needs to be asserted to theory
* @param preRegister whether to preregister the atom with the theory
* @param canErase whether the sat solver can safely eliminate this variable
*
*/
virtual SatVariable newVar(bool isTheoryAtom, bool preRegister, bool canErase) = 0;
/** Create a new (or return an existing) boolean variable representing the constant true */
virtual SatVariable trueVar() = 0;
/** Create a new (or return an existing) boolean variable representing the constant false */
virtual SatVariable falseVar() = 0;
/** Check the satisfiability of the added clauses */
virtual SatValue solve() = 0;
/** Check the satisfiability of the added clauses */
virtual SatValue solve(long unsigned int&) = 0;
/** Check satisfiability under assumptions */
virtual SatValue solve(const std::vector<SatLiteral>& assumptions)
{
Unimplemented() << "Solving under assumptions not implemented";
};
/** Interrupt the solver */
virtual void interrupt() = 0;
/** Call value() during the search.*/
virtual SatValue value(SatLiteral l) = 0;
/** Call modelValue() when the search is done.*/
virtual SatValue modelValue(SatLiteral l) = 0;
/** Get the current assertion level */
virtual unsigned getAssertionLevel() const = 0;
/** Check if the solver is in an inconsistent state */
virtual bool ok() const = 0;
virtual void setResolutionProofLog(proof::ResolutionBitVectorProof* bvp) {}
virtual void setClausalProofLog(proof::ClausalBitVectorProof* drat_proof) {}
};/* class SatSolver */
class BVSatSolverInterface: public SatSolver {
public:
virtual ~BVSatSolverInterface() {}
/** Interface for notifications */
virtual void setNotify(BVSatSolverNotify* notify) = 0;
virtual void markUnremovable(SatLiteral lit) = 0;
virtual void getUnsatCore(SatClause& unsatCore) = 0;
virtual void addMarkerLiteral(SatLiteral lit) = 0;
virtual SatValue propagate() = 0;
virtual void explain(SatLiteral lit, std::vector<SatLiteral>& explanation) = 0;
virtual SatValue assertAssumption(SatLiteral lit, bool propagate = false) = 0;
virtual void popAssumption() = 0;
};/* class BVSatSolverInterface */
class DPLLSatSolverInterface: public SatSolver {
public:
virtual void initialize(context::Context* context, prop::TheoryProxy* theoryProxy) = 0;
virtual void push() = 0;
virtual void pop() = 0;
/*
* Reset the decisions in the DPLL(T) SAT solver at the current assertion
* level.
*/
virtual void resetTrail() = 0;
virtual bool properExplanation(SatLiteral lit, SatLiteral expl) const = 0;
virtual void requirePhase(SatLiteral lit) = 0;
virtual bool isDecision(SatVariable decn) const = 0;
};/* class DPLLSatSolverInterface */
inline std::ostream& operator <<(std::ostream& out, prop::SatLiteral lit) {
out << lit.toString();
return out;
}
inline std::ostream& operator <<(std::ostream& out, const prop::SatClause& clause) {
out << "clause:";
for(unsigned i = 0; i < clause.size(); ++i) {
out << " " << clause[i];
}
out << ";";
return out;
}
inline std::ostream& operator <<(std::ostream& out, prop::SatValue val) {
std::string str;
switch(val) {
case prop::SAT_VALUE_UNKNOWN:
str = "_";
break;
case prop::SAT_VALUE_TRUE:
str = "1";
break;
case prop::SAT_VALUE_FALSE:
str = "0";
break;
default:
str = "Error";
break;
}
out << str;
return out;
}
}/* CVC4::prop namespace */
}/* CVC4 namespace */
#endif /* CVC4__PROP__SAT_MODULE_H */
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