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/********************* */
/*! \file cad_solver.h
** \verbatim
** Top contributors (to current version):
** Gereon Kremer
** This file is part of the CVC4 project.
** Copyright (c) 2009-2021 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 CAD-based solver based on https://arxiv.org/pdf/2003.05633.pdf.
**/
#ifndef CVC4__THEORY__ARITH__CAD_SOLVER_H
#define CVC4__THEORY__ARITH__CAD_SOLVER_H
#include <vector>
#include "context/context.h"
#include "expr/node.h"
#include "theory/arith/nl/cad/cdcac.h"
#include "theory/arith/nl/cad/proof_checker.h"
namespace cvc5 {
class ProofNodeManager;
namespace theory {
namespace arith {
class InferenceManager;
namespace nl {
class NlModel;
/**
* A solver for nonlinear arithmetic that implements the CAD-based method
* described in https://arxiv.org/pdf/2003.05633.pdf.
*/
class CadSolver
{
public:
CadSolver(InferenceManager& im,
NlModel& model,
context::Context* ctx,
ProofNodeManager* pnm);
~CadSolver();
/**
* This is called at the beginning of last call effort check, where
* assertions are the set of assertions belonging to arithmetic,
* false_asserts is the subset of assertions that are false in the current
* model, and xts is the set of extended function terms that are active in
* the current context.
*/
void initLastCall(const std::vector<Node>& assertions);
/**
* Perform a full check, returning either {} or a single lemma.
* If the result is empty, the input is satisfiable and a model is available
* for construct_model_if_available. Otherwise, the single lemma can be used
* as an infeasible subset.
*/
void checkFull();
/**
* Perform a partial check, returning either {} or a list of lemmas.
* If the result is empty, the input is satisfiable and a model is available
* for construct_model_if_available. Otherwise, the lemmas exclude some part
* of the search space.
*/
void checkPartial();
/**
* If a model is available (indicated by the last call to check_full() or
* check_partial()) this method puts a satisfying assignment in d_model,
* clears the list of assertions, and returns true.
* Otherwise, this method returns false.
*/
bool constructModelIfAvailable(std::vector<Node>& assertions);
private:
/**
* The variable used to encode real algebraic numbers to nodes.
*/
Node d_ranVariable;
#ifdef CVC4_POLY_IMP
/**
* The object implementing the actual decision procedure.
*/
cad::CDCAC d_CAC;
/** The proof checker for cad proofs */
cad::CADProofRuleChecker d_proofChecker;
#endif
/**
* Indicates whether we found satisfiability in the last call to
* checkFullRefine.
*/
bool d_foundSatisfiability;
/** The inference manager we are pushing conflicts and lemmas to. */
InferenceManager& d_im;
/** Reference to the non-linear model object */
NlModel& d_model;
}; /* class CadSolver */
} // namespace nl
} // namespace arith
} // namespace theory
} // namespace cvc5
#endif /* CVC4__THEORY__ARITH__CAD_SOLVER_H */
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