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/********************* */
/** prop_engine.h
** Original author: mdeters
** Major contributors: taking
** Minor contributors (to current version): dejan
** 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.
**
** The PropEngine (proposiitonal engine); main interface point
** between CVC4's SMT infrastructure and the SAT solver.
**/
#ifndef __CVC4__PROP_ENGINE_H
#define __CVC4__PROP_ENGINE_H
#include "cvc4_config.h"
#include "expr/node.h"
#include "util/decision_engine.h"
#include "theory/theory_engine.h"
#include "prop/minisat/simp/SimpSolver.h"
#include "prop/minisat/core/SolverTypes.h"
#include "util/result.h"
#include <map>
#include "prop/cnf_stream.h"
namespace CVC4 {
namespace prop {
class CnfStream;
}
class Options;
}
namespace CVC4 {
// In terms of abstraction, this is below (and provides services to)
// Prover and above (and requires the services of) a specific
// propositional solver, DPLL or otherwise.
class PropEngine {
const Options *d_opts;
DecisionEngine &d_de;
TheoryEngine &d_te;
friend class CVC4::prop::CnfStream;
/**
* The SAT solver.
*/
CVC4::prop::minisat::Solver* d_sat;
std::map<Node, CVC4::prop::minisat::Var> d_atom2var;
std::map<CVC4::prop::minisat::Var, Node> d_var2atom;
/**
* Requests a fresh variable from d_sat, v.
* Adds mapping of n -> v to d_node2var, and
* a mapping of v -> n to d_var2node.
*/
CVC4::prop::minisat::Var registerAtom(const Node & n);
/**
* Requests a fresh variable from d_sat.
*/
CVC4::prop::minisat::Var requestFreshVar();
/**
* Returns true iff this Node is in the atom to variable mapping.
* @param n the Node to lookup
* @return true iff this Node is in the atom to variable mapping.
*/
bool isAtomMapped(const Node & n) const;
/**
* Returns the variable mapped by the atom Node.
* @param n the atom to do the lookup by
* @return the corresponding variable
*/
CVC4::prop::minisat::Var lookupAtom(const Node & n) const;
/**
* Flags whether the solver may need to have its state reset before
* solving occurs
*/
bool d_restartMayBeNeeded;
/**
* Cleans existing state in the PropEngine and reinitializes the state.
*/
void restart();
/**
* Keeps track of all of the assertions that need to be made.
*/
std::vector<Node> d_assertionList;
/**
* Returns true iff the minisat var has been mapped to an atom.
* @param v variable to check if it is mapped
* @return returns true iff the minisat var has been mapped.
*/
bool isVarMapped(CVC4::prop::minisat::Var v) const;
/**
* Returns the atom mapped by the variable v.
* @param v the variable to do the lookup by
* @return an atom
*/
Node lookupVar(CVC4::prop::minisat::Var v) const;
/**
* Asserts an internally constructed clause.
* Each literal is assumed to be in the 1:1 mapping contained in d_node2lit & d_lit2node.
* @param c the clause to be asserted.
*/
void assertClause(CVC4::prop::minisat::vec<CVC4::prop::minisat::Lit> & c);
/** The CNF converter in use */
CVC4::prop::CnfStream *d_cnfStream;
void assertLit(CVC4::prop::minisat::Lit l);
void signalBooleanPropHasEnded();
public:
/**
* Create a PropEngine with a particular decision and theory engine.
*/
CVC4_PUBLIC PropEngine(const CVC4::Options* opts,
CVC4::DecisionEngine&,
CVC4::TheoryEngine&);
CVC4_PUBLIC ~PropEngine();
/**
* Converts the given formula to CNF and assert the CNF to the sat solver.
*/
void assertFormula(const Node& node);
/**
* Currently this takes a well-formed* Node,
* converts it to a propositionally equisatisifiable formula for a sat solver,
* and invokes the sat solver for a satisfying assignment.
* TODO: what does well-formed mean here?
*/
Result solve();
};/* class PropEngine */
inline bool PropEngine::isAtomMapped(const Node & n) const{
return d_atom2var.find(n) != d_atom2var.end();
}
inline CVC4::prop::minisat::Var PropEngine::lookupAtom(const Node & n) const{
Assert(isAtomMapped(n));
return d_atom2var.find(n)->second;
}
inline bool PropEngine::isVarMapped(CVC4::prop::minisat::Var v) const {
return d_var2atom.find(v) != d_var2atom.end();
}
inline Node PropEngine::lookupVar(CVC4::prop::minisat::Var v) const {
Assert(isVarMapped(v));
return d_var2atom.find(v)->second;
}
}/* CVC4 namespace */
#endif /* __CVC4__PROP_ENGINE_H */
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