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/********************* */
/*! \file cad_solver.cpp
** \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 Implementation of new non-linear solver
**/
#include "theory/arith/nl/cad_solver.h"
#include "theory/inference_id.h"
#include "theory/arith/inference_manager.h"
#include "theory/arith/nl/cad/cdcac.h"
#include "theory/arith/nl/nl_model.h"
#include "theory/arith/nl/poly_conversion.h"
namespace CVC4 {
namespace theory {
namespace arith {
namespace nl {
CadSolver::CadSolver(InferenceManager& im,
NlModel& model,
context::Context* ctx,
ProofNodeManager* pnm)
:
#ifdef CVC4_POLY_IMP
d_CAC(ctx, pnm),
#endif
d_foundSatisfiability(false),
d_im(im),
d_model(model)
{
d_ranVariable =
NodeManager::currentNM()->mkSkolem("__z",
NodeManager::currentNM()->realType(),
"",
NodeManager::SKOLEM_EXACT_NAME);
#ifdef CVC4_POLY_IMP
ProofChecker* pc = pnm != nullptr ? pnm->getChecker() : nullptr;
if (pc != nullptr)
{
// add checkers
d_proofChecker.registerTo(pc);
}
#endif
}
CadSolver::~CadSolver() {}
void CadSolver::initLastCall(const std::vector<Node>& assertions)
{
#ifdef CVC4_POLY_IMP
if (Trace.isOn("nl-cad"))
{
Trace("nl-cad") << "CadSolver::initLastCall" << std::endl;
Trace("nl-cad") << "* Assertions: " << std::endl;
for (const Node& a : assertions)
{
Trace("nl-cad") << " " << a << std::endl;
}
}
// store or process assertions
d_CAC.reset();
for (const Node& a : assertions)
{
d_CAC.getConstraints().addConstraint(a);
}
d_CAC.computeVariableOrdering();
d_CAC.retrieveInitialAssignment(d_model, d_ranVariable);
#else
Warning() << "Tried to use CadSolver but libpoly is not available. Compile "
"with --poly."
<< std::endl;
#endif
}
void CadSolver::checkFull()
{
#ifdef CVC4_POLY_IMP
if (d_CAC.getConstraints().getConstraints().empty()) {
Trace("nl-cad") << "No constraints. Return." << std::endl;
return;
}
d_CAC.startNewProof();
auto covering = d_CAC.getUnsatCover();
if (covering.empty())
{
d_foundSatisfiability = true;
Trace("nl-cad") << "SAT: " << d_CAC.getModel() << std::endl;
}
else
{
d_foundSatisfiability = false;
auto mis = collectConstraints(covering);
Trace("nl-cad") << "Collected MIS: " << mis << std::endl;
Assert(!mis.empty()) << "Infeasible subset can not be empty";
Trace("nl-cad") << "UNSAT with MIS: " << mis << std::endl;
Node lem = NodeManager::currentNM()->mkAnd(mis).negate();
ProofGenerator* proof = d_CAC.closeProof(mis);
d_im.addPendingLemma(lem, InferenceId::ARITH_NL_CAD_CONFLICT, proof);
}
#else
Warning() << "Tried to use CadSolver but libpoly is not available. Compile "
"with --poly."
<< std::endl;
#endif
}
void CadSolver::checkPartial()
{
#ifdef CVC4_POLY_IMP
if (d_CAC.getConstraints().getConstraints().empty()) {
Trace("nl-cad") << "No constraints. Return." << std::endl;
return;
}
auto covering = d_CAC.getUnsatCover(0, true);
if (covering.empty())
{
d_foundSatisfiability = true;
Trace("nl-cad") << "SAT: " << d_CAC.getModel() << std::endl;
}
else
{
auto* nm = NodeManager::currentNM();
Node first_var =
d_CAC.getConstraints().varMapper()(d_CAC.getVariableOrdering()[0]);
for (const auto& interval : covering)
{
Node premise;
Assert(!interval.d_origins.empty());
if (interval.d_origins.size() == 1)
{
premise = interval.d_origins[0];
}
else
{
premise = nm->mkNode(Kind::AND, interval.d_origins);
}
Node conclusion =
excluding_interval_to_lemma(first_var, interval.d_interval, false);
if (!conclusion.isNull())
{
Node lemma = nm->mkNode(Kind::IMPLIES, premise, conclusion);
Trace("nl-cad") << "Excluding " << first_var << " -> "
<< interval.d_interval << " using " << lemma
<< std::endl;
d_im.addPendingLemma(lemma,
InferenceId::ARITH_NL_CAD_EXCLUDED_INTERVAL);
}
}
}
#else
Warning() << "Tried to use CadSolver but libpoly is not available. Compile "
"with --poly."
<< std::endl;
#endif
}
bool CadSolver::constructModelIfAvailable(std::vector<Node>& assertions)
{
#ifdef CVC4_POLY_IMP
if (!d_foundSatisfiability)
{
return false;
}
bool foundNonVariable = false;
for (const auto& v : d_CAC.getVariableOrdering())
{
Node variable = d_CAC.getConstraints().varMapper()(v);
if (!variable.isVar())
{
Trace("nl-cad") << "Not a variable: " << variable << std::endl;
foundNonVariable = true;
}
Node value = value_to_node(d_CAC.getModel().get(v), d_ranVariable);
if (value.isConst())
{
d_model.addCheckModelSubstitution(variable, value);
}
else
{
d_model.addCheckModelWitness(variable, value);
}
Trace("nl-cad") << "-> " << v << " = " << value << std::endl;
}
if (foundNonVariable)
{
Trace("nl-cad")
<< "Some variable was an extended term, don't clear list of assertions."
<< std::endl;
return false;
}
Trace("nl-cad") << "Constructed a full assignment, clear list of assertions."
<< std::endl;
assertions.clear();
return true;
#else
Warning() << "Tried to use CadSolver but libpoly is not available. Compile "
"with --poly."
<< std::endl;
return false;
#endif
}
} // namespace nl
} // namespace arith
} // namespace theory
} // namespace CVC4
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