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/********************* */
/*! \file interpolation_solver.cpp
** \verbatim
** Top contributors (to current version):
** Ying Sheng
** This file is part of the CVC4 project.
** Copyright (c) 2009-2020 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 The solver for interpolation queries
**/
#include "smt/interpolation_solver.h"
#include "options/smt_options.h"
#include "smt/smt_engine.h"
#include "theory/quantifiers/quantifiers_attributes.h"
#include "theory/quantifiers/sygus/sygus_grammar_cons.h"
#include "theory/quantifiers/sygus/sygus_interpol.h"
#include "theory/smt_engine_subsolver.h"
using namespace CVC4::theory;
namespace CVC4 {
namespace smt {
InterpolationSolver::InterpolationSolver(SmtEngine* parent) : d_parent(parent)
{
}
InterpolationSolver::~InterpolationSolver() {}
bool InterpolationSolver::getInterpol(const Node& conj,
const TypeNode& grammarType,
Node& interpol)
{
if (options::produceInterpols() == options::ProduceInterpols::NONE)
{
const char* msg =
"Cannot get interpolation when produce-interpol options is off.";
throw ModalException(msg);
}
Trace("sygus-interpol") << "SmtEngine::getInterpol: conjecture " << conj
<< std::endl;
std::vector<Expr> easserts = d_parent->getExpandedAssertions();
std::vector<Node> axioms;
for (unsigned i = 0, size = easserts.size(); i < size; i++)
{
axioms.push_back(Node::fromExpr(easserts[i]));
}
// must expand definitions
Node conjn = d_parent->expandDefinitions(conj);
std::string name("A");
quantifiers::SygusInterpol interpolSolver;
if (interpolSolver.SolveInterpolation(
name, axioms, conjn, grammarType, interpol))
{
if (options::checkInterpols())
{
checkInterpol(interpol.toExpr(), easserts, conj);
}
return true;
}
return false;
}
bool InterpolationSolver::getInterpol(const Node& conj, Node& interpol)
{
TypeNode grammarType;
return getInterpol(conj, grammarType, interpol);
}
void InterpolationSolver::checkInterpol(Expr interpol,
const std::vector<Expr>& easserts,
const Node& conj)
{
Assert(interpol.getType().isBoolean());
Trace("check-interpol") << "SmtEngine::checkInterpol: get expanded assertions"
<< std::endl;
// two checks: first, axioms imply interpol, second, interpol implies conj.
for (unsigned j = 0; j < 2; j++)
{
if (j == 1)
{
Trace("check-interpol") << "SmtEngine::checkInterpol: conjecture is "
<< conj.toExpr() << std::endl;
}
Trace("check-interpol") << "SmtEngine::checkInterpol: phase " << j
<< ": make new SMT engine" << std::endl;
// Start new SMT engine to check solution
std::unique_ptr<SmtEngine> itpChecker;
initializeSubsolver(itpChecker);
Trace("check-interpol") << "SmtEngine::checkInterpol: phase " << j
<< ": asserting formulas" << std::endl;
if (j == 0)
{
for (const Expr& e : easserts)
{
itpChecker->assertFormula(e);
}
Expr negitp = interpol.notExpr();
itpChecker->assertFormula(negitp);
}
else
{
itpChecker->assertFormula(interpol);
Assert(!conj.isNull());
itpChecker->assertFormula(conj.toExpr().notExpr());
}
Trace("check-interpol") << "SmtEngine::checkInterpol: phase " << j
<< ": check the assertions" << std::endl;
Result r = itpChecker->checkSat();
Trace("check-interpol") << "SmtEngine::checkInterpol: phase " << j
<< ": result is " << r << std::endl;
std::stringstream serr;
if (r.asSatisfiabilityResult().isSat() != Result::UNSAT)
{
if (j == 0)
{
serr << "SmtEngine::checkInterpol(): negated produced solution cannot "
"be shown "
"satisfiable with assertions, result was "
<< r;
}
else
{
serr
<< "SmtEngine::checkInterpol(): negated conjecture cannot be shown "
"satisfiable with produced solution, result was "
<< r;
}
InternalError() << serr.str();
}
}
}
} // namespace smt
} // namespace CVC4
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