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/********************* */
/** sat.h
** Original author: mdeters
** Major contributors: dejan
** Minor contributors (to current version): none
** This file is part of the CVC4 prototype.
** Copyright (c) 2009, 2010 The Analysis of Computer Systems Group (ACSys)
** Courant Institute of Mathematical Sciences
** New York University
** See the file COPYING in the top-level source directory for licensing
** information.
**
** SAT Solver.
**/
#ifndef __CVC4__PROP__SAT_H
#define __CVC4__PROP__SAT_H
#include "cvc4_private.h"
#define __CVC4_USE_MINISAT
#ifdef __CVC4_USE_MINISAT
#include "util/options.h"
#include "prop/minisat/core/Solver.h"
#include "prop/minisat/core/SolverTypes.h"
#include "prop/minisat/simp/SimpSolver.h"
namespace CVC4 {
class TheoryEngine;
namespace prop {
class PropEngine;
class CnfStream;
/** Type of the SAT variables */
typedef minisat::Var SatVariable;
/** Type of the Sat literals */
typedef minisat::Lit SatLiteral;
/** Type of the SAT clauses */
typedef minisat::vec<SatLiteral> SatClause;
/**
* The proxy class that allows us to modify the internals of the SAT solver.
* It's only accessible from the PropEngine, and should be treated with major
* care.
*/
class SatSolver {
/** The prop engine we are using */
PropEngine* d_propEngine;
/** The CNF engine we are using */
CnfStream* d_cnfStream;
/** The theory engine we are using */
TheoryEngine* d_theoryEngine;
/** Context we will be using to synchronzie the sat solver */
context::Context* d_context;
/** Minisat solver */
minisat::SimpSolver* d_minisat;
/** Remember the options */
Options* d_options;
public:
/** Hash function for literals */
struct SatLiteralHashFcn {
inline size_t operator()(const SatLiteral& literal) const;
};
inline SatSolver(PropEngine* propEngine,
TheoryEngine* theoryEngine,
context::Context* context,
const Options* options);
inline ~SatSolver();
inline bool solve();
inline void addClause(SatClause& clause);
inline SatVariable newVar(bool theoryAtom = false);
inline void theoryCheck(SatClause& conflict);
inline void enqueueTheoryLiteral(const SatLiteral& l);
inline void setCnfStream(CnfStream* cnfStream);
};
}/* CVC4::prop namespace */
}/* CVC4 namespace */
#include "context/context.h"
#include "theory/theory_engine.h"
#include "prop/prop_engine.h"
#include "prop/cnf_stream.h"
namespace CVC4 {
namespace prop {
/**
* Returns the variable of the literal.
* @param lit the literal
*/
inline SatVariable literalToVariable(SatLiteral lit) {
return minisat::var(lit);
}
inline bool literalSign(SatLiteral lit) {
return minisat::sign(lit);
}
inline std::ostream& operator <<(std::ostream& out, SatLiteral lit) {
const char * s = (literalSign(lit)) ? "~" : " ";
out << s << literalToVariable(lit);
return out;
}
inline std::ostream& operator <<(std::ostream& out, const SatClause& clause) {
out << "clause:";
for(int i = 0; i < clause.size(); ++i) {
out << " " << clause[i];
}
out << ";";
return out;
}
inline size_t
SatSolver::SatLiteralHashFcn::operator()(const SatLiteral& literal) const {
return (size_t) minisat::toInt(literal);
}
SatSolver::SatSolver(PropEngine* propEngine, TheoryEngine* theoryEngine,
context::Context* context, const Options* options) :
d_propEngine(propEngine),
d_cnfStream(NULL),
d_theoryEngine(theoryEngine),
d_context(context)
{
// Create the solver
d_minisat = new minisat::SimpSolver(this, d_context);
// Setup the verbosity
d_minisat->verbosity = (options->verbosity > 0) ? 1 : -1;
// Do not delete the satisfied clauses, just the learnt ones
d_minisat->remove_satisfied = false;
// Make minisat reuse the literal values
d_minisat->polarity_mode = minisat::SimpSolver::polarity_user;
}
SatSolver::~SatSolver() {
delete d_minisat;
}
bool SatSolver::solve() {
return d_minisat->solve();
}
void SatSolver::addClause(SatClause& clause) {
d_minisat->addClause(clause);
}
SatVariable SatSolver::newVar(bool theoryAtom) {
return d_minisat->newVar(true, true, theoryAtom);
}
void SatSolver::theoryCheck(SatClause& conflict) {
// Try theory propagation
if (!d_theoryEngine->check(theory::Theory::FULL_EFFORT)) {
// We have a conflict, get it
Node conflictNode = d_theoryEngine->getConflict();
Debug("prop") << "SatSolver::theoryCheck() => conflict: " << conflictNode << std::endl;
// Go through the literals and construct the conflict clause
Node::const_iterator literal_it = conflictNode.begin();
Node::const_iterator literal_end = conflictNode.end();
while (literal_it != literal_end) {
// Get the literal corresponding to the node
SatLiteral l = d_cnfStream->getLiteral(*literal_it);
// Add the negation to the conflict clause and continue
conflict.push(~l);
literal_it ++;
}
}
}
void SatSolver::enqueueTheoryLiteral(const SatLiteral& l) {
Node literalNode = d_cnfStream->getNode(l);
// We can get null from the prop engine if the literal is useless (i.e.)
// the expression is not in context anyomore
if(!literalNode.isNull()) {
d_theoryEngine->assertFact(literalNode);
}
}
void SatSolver::setCnfStream(CnfStream* cnfStream) {
d_cnfStream = cnfStream;
}
}/* CVC4::prop namespace */
}/* CVC4 namespace */
#endif
#endif /* __CVC4__PROP__SAT_H */
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