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/********************* */
/*! \file decision_engine.h
** \verbatim
** Original author: kshitij
** Major contributors: none
** Minor contributors (to current version): barrett, dejan, mdeters
** This file is part of the CVC4 prototype.
** Copyright (c) 2009-2012 New York University and The University of Iowa
** See the file COPYING in the top-level source directory for licensing
** information.\endverbatim
**
** \brief Decision engine
**
** Decision engine
**/
#include "cvc4_private.h"
#ifndef __CVC4__DECISION__DECISION_ENGINE_H
#define __CVC4__DECISION__DECISION_ENGINE_H
#include <vector>
#include "decision/decision_strategy.h"
#include "expr/node.h"
#include "prop/cnf_stream.h"
#include "prop/prop_engine.h"
#include "prop/sat_solver_types.h"
#include "util/ite_removal.h"
#include "util/output.h"
using namespace std;
using namespace CVC4::prop;
using namespace CVC4::decision;
namespace CVC4 {
class DecisionEngine {
vector <DecisionStrategy* > d_enabledStrategies;
vector <ITEDecisionStrategy* > d_needIteSkolemMap;
RelevancyStrategy* d_relevancyStrategy;
vector <Node> d_assertions;
// PropEngine* d_propEngine;
CnfStream* d_cnfStream;
DPLLSatSolverInterface* d_satSolver;
context::Context* d_satContext;
context::Context* d_userContext;
// Does decision engine know the answer?
context::CDO<SatValue> d_result;
// Disable creating decision engine without required parameters
DecisionEngine() : d_result(NULL) {}
// init/shutdown state
unsigned d_engineState; // 0=pre-init; 1=init,pre-shutdown; 2=shutdown
public:
// Necessary functions
/** Constructor */
DecisionEngine(context::Context *sc, context::Context *uc);
/** Destructor, currently does nothing */
~DecisionEngine() {
Trace("decision") << "Destroying decision engine" << std::endl;
for(unsigned i = 0; i < d_enabledStrategies.size(); ++i)
delete d_enabledStrategies[i];
}
// void setPropEngine(PropEngine* pe) {
// // setPropEngine should not be called more than once
// Assert(d_propEngine == NULL);
// Assert(pe != NULL);
// d_propEngine = pe;
// }
void setSatSolver(DPLLSatSolverInterface* ss) {
// setPropEngine should not be called more than once
Assert(d_satSolver == NULL);
Assert(ss != NULL);
d_satSolver = ss;
}
void setCnfStream(CnfStream* cs) {
// setPropEngine should not be called more than once
Assert(d_cnfStream == NULL);
Assert(cs != NULL);
d_cnfStream = cs;
}
/* enables decision stragies based on options */
void init();
/**
* This is called by SmtEngine, at shutdown time, just before
* destruction. It is important because there are destruction
* ordering issues between some parts of the system. For now,
* there's nothing to do here in the DecisionEngine.
*/
void shutdown() {
Assert(d_engineState == 1);
d_engineState = 2;
Trace("decision") << "Shutting down decision engine" << std::endl;
}
// Interface for External World to use our services
/** Gets the next decision based on strategies that are enabled */
SatLiteral getNext(bool &stopSearch) {
Assert(d_cnfStream != NULL,
"Forgot to set cnfStream for decision engine?");
Assert(d_satSolver != NULL,
"Forgot to set satSolver for decision engine?");
SatLiteral ret = undefSatLiteral;
for(unsigned i = 0;
i < d_enabledStrategies.size()
and ret == undefSatLiteral
and stopSearch == false; ++i) {
ret = d_enabledStrategies[i]->getNext(stopSearch);
}
return ret;
}
/** Is a sat variable relevant */
bool isRelevant(SatVariable var);
/**
* Try to get tell SAT solver what polarity to try for a
* decision. Return SAT_VALUE_UNKNOWN if it can't help
*/
SatValue getPolarity(SatVariable var);
/** Is the DecisionEngine in a state where it has solved everything? */
bool isDone() {
Trace("decision") << "DecisionEngine::isDone() returning "
<< (d_result != SAT_VALUE_UNKNOWN)
<< (d_result != SAT_VALUE_UNKNOWN ? "true" : "false")
<< std::endl;
return (d_result != SAT_VALUE_UNKNOWN);
}
/** */
Result getResult() {
switch(d_result.get()) {
case SAT_VALUE_TRUE: return Result(Result::SAT);
case SAT_VALUE_FALSE: return Result(Result::UNSAT);
case SAT_VALUE_UNKNOWN: return Result(Result::SAT_UNKNOWN, Result::UNKNOWN_REASON);
default: Assert(false, "d_result is garbage");
}
return Result();
}
/** */
void setResult(SatValue val) {
d_result = val;
}
// External World helping us help the Strategies
/** If one of the enabled strategies needs them */
/* bool needIteSkolemMap() { */
/* return d_needIteSkolemMap.size() > 0; */
/* } */
/* add a set of assertions */
void addAssertions(const vector<Node> &assertions);
/**
* add a set of assertions, while providing a mapping between skolem
* variables and corresponding assertions. It is assumed that all
* assertions after assertionEnd were generated by ite
* removal. Hence, iteSkolemMap maps into only these.
*/
void addAssertions(const vector<Node> &assertions,
unsigned assertionsEnd,
IteSkolemMap iteSkolemMap);
/* add a single assertion */
void addAssertion(Node n);
// Interface for Strategies to use stuff stored in Decision Engine
// (which was possibly requested by them on initialization)
/**
* Get the assertions. Strategies are notified when these are available.
*/
const vector<Node>& getAssertions() {
return d_assertions;
}
// Interface for Strategies to get information about External World
bool hasSatLiteral(TNode n) {
return d_cnfStream->hasLiteral(n);
}
SatLiteral getSatLiteral(TNode n) {
return d_cnfStream->getLiteral(n);
}
SatValue getSatValue(SatLiteral l) {
return d_satSolver->value(l);
}
SatValue getSatValue(TNode n) {
return getSatValue(getSatLiteral(n));
}
Node getNode(SatLiteral l) {
return d_cnfStream->getNode(l);
}
private:
/**
* Enable a particular decision strategy, also updating
* corresponding vector<DecisionStrategy*>-s is the engine
*/
void enableStrategy(DecisionStrategy* ds);
};/* DecisionEngine class */
}/* CVC4 namespace */
#endif /* __CVC4__DECISION__DECISION_ENGINE_H */
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