GCC Code Coverage Report
Directory: . Exec Total Coverage
File: src/theory/arith/theory_arith.cpp Lines: 154 180 85.6 %
Date: 2021-09-29 Branches: 193 514 37.5 %

Line Exec Source
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/******************************************************************************
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 * Top contributors (to current version):
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 *   Andrew Reynolds, Tim King, Alex Ozdemir
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 *
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 * This file is part of the cvc5 project.
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 *
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 * Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
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 * in the top-level source directory and their institutional affiliations.
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 * All rights reserved.  See the file COPYING in the top-level source
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 * directory for licensing information.
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 * ****************************************************************************
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 *
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 * Arithmetic theory.
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 */
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#include "theory/arith/theory_arith.h"
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#include "options/smt_options.h"
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#include "proof/proof_checker.h"
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#include "proof/proof_rule.h"
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#include "smt/smt_statistics_registry.h"
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#include "theory/arith/arith_rewriter.h"
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#include "theory/arith/equality_solver.h"
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#include "theory/arith/infer_bounds.h"
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#include "theory/arith/nl/nonlinear_extension.h"
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#include "theory/arith/theory_arith_private.h"
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#include "theory/ext_theory.h"
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#include "theory/rewriter.h"
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#include "theory/theory_model.h"
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using namespace std;
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using namespace cvc5::kind;
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namespace cvc5 {
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namespace theory {
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namespace arith {
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6271
TheoryArith::TheoryArith(Env& env, OutputChannel& out, Valuation valuation)
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    : Theory(THEORY_ARITH, env, out, valuation),
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      d_ppRewriteTimer(
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12542
          statisticsRegistry().registerTimer("theory::arith::ppRewriteTimer")),
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      d_astate(env, valuation),
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      d_im(env, *this, d_astate, d_pnm),
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      d_ppre(context(), d_pnm),
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      d_bab(env, d_astate, d_im, d_ppre, d_pnm),
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      d_eqSolver(nullptr),
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6271
      d_internal(new TheoryArithPrivate(*this, env, d_bab)),
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      d_nonlinearExtension(nullptr),
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      d_opElim(d_pnm, logicInfo()),
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      d_arithPreproc(env, d_astate, d_im, d_pnm, d_opElim),
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25084
      d_rewriter(d_opElim)
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{
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  // currently a cyclic dependency to TheoryArithPrivate
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6271
  d_astate.setParent(d_internal);
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  // indicate we are using the theory state object and inference manager
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6271
  d_theoryState = &d_astate;
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6271
  d_inferManager = &d_im;
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6271
  if (options().arith.arithEqSolver)
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  {
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    d_eqSolver.reset(new EqualitySolver(env, d_astate, d_im));
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  }
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6271
}
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18804
TheoryArith::~TheoryArith(){
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6268
  delete d_internal;
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12536
}
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6271
TheoryRewriter* TheoryArith::getTheoryRewriter() { return &d_rewriter; }
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ProofRuleChecker* TheoryArith::getProofChecker()
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{
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  return d_internal->getProofChecker();
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}
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6271
bool TheoryArith::needsEqualityEngine(EeSetupInfo& esi)
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{
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  // if the equality solver is enabled, then it is responsible for setting
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  // up the equality engine
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6271
  if (d_eqSolver != nullptr)
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  {
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    return d_eqSolver->needsEqualityEngine(esi);
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  }
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  // otherwise, the linear arithmetic solver is responsible for setting up
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  // the equality engine
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6256
  return d_internal->needsEqualityEngine(esi);
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}
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6271
void TheoryArith::finishInit()
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{
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6271
  const LogicInfo& logic = logicInfo();
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6271
  if (logic.isTheoryEnabled(THEORY_ARITH) && logic.areTranscendentalsUsed())
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  {
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    // witness is used to eliminate square root
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2758
    d_valuation.setUnevaluatedKind(kind::WITNESS);
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    // we only need to add the operators that are not syntax sugar
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    d_valuation.setUnevaluatedKind(kind::EXPONENTIAL);
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    d_valuation.setUnevaluatedKind(kind::SINE);
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    d_valuation.setUnevaluatedKind(kind::PI);
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  }
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  // only need to create nonlinear extension if non-linear logic
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6271
  if (logic.isTheoryEnabled(THEORY_ARITH) && !logic.isLinear())
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  {
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6858
    d_nonlinearExtension.reset(
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        new nl::NonlinearExtension(d_env, *this, d_astate));
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  }
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6271
  if (d_eqSolver != nullptr)
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  {
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    d_eqSolver->finishInit();
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  }
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  // finish initialize in the old linear solver
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6271
  d_internal->finishInit();
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6271
}
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433390
void TheoryArith::preRegisterTerm(TNode n)
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{
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433390
  if (d_nonlinearExtension != nullptr)
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  {
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212306
    d_nonlinearExtension->preRegisterTerm(n);
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  }
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433391
  d_internal->preRegisterTerm(n);
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433389
}
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414355
void TheoryArith::notifySharedTerm(TNode n) { d_internal->notifySharedTerm(n); }
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TrustNode TheoryArith::ppRewrite(TNode atom, std::vector<SkolemLemma>& lems)
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{
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  CodeTimer timer(d_ppRewriteTimer, /* allow_reentrant = */ true);
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410713
  Debug("arith::preprocess") << "arith::preprocess() : " << atom << endl;
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410713
  if (atom.getKind() == kind::EQUAL)
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  {
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    return d_ppre.ppRewriteEq(atom);
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  }
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398211
  Assert(Theory::theoryOf(atom) == THEORY_ARITH);
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  // Eliminate operators. Notice we must do this here since other
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  // theories may generate lemmas that involve non-standard operators. For
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  // example, quantifier instantiation may use TO_INTEGER terms; SyGuS may
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  // introduce non-standard arithmetic terms appearing in grammars.
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  // call eliminate operators. In contrast to expandDefinitions, we eliminate
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  // *all* extended arithmetic operators here, including total ones.
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398217
  return d_arithPreproc.eliminate(atom, lems, false);
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}
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Theory::PPAssertStatus TheoryArith::ppAssert(
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    TrustNode tin, TrustSubstitutionMap& outSubstitutions)
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{
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  return d_internal->ppAssert(tin, outSubstitutions);
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}
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void TheoryArith::ppStaticLearn(TNode n, NodeBuilder& learned)
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{
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  d_internal->ppStaticLearn(n, learned);
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63519
}
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1175392
bool TheoryArith::preCheck(Effort level)
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{
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1175392
  Trace("arith-check") << "TheoryArith::preCheck " << level << std::endl;
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1175392
  return d_internal->preCheck(level);
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}
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1175392
void TheoryArith::postCheck(Effort level)
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{
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1175392
  d_im.reset();
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1175392
  Trace("arith-check") << "TheoryArith::postCheck " << level << std::endl;
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  // check with the non-linear solver at last call
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1175392
  if (level == Theory::EFFORT_LAST_CALL)
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  {
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    if (d_nonlinearExtension != nullptr)
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    {
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      // If we computed lemmas in the last FULL_EFFORT check, send them now.
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      if (d_im.hasPendingLemma())
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      {
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1328
        d_im.doPendingFacts();
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        d_im.doPendingLemmas();
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1328
        d_im.doPendingPhaseRequirements();
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1328
        return;
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      }
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      d_nonlinearExtension->finalizeModel(getValuation().getModel());
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    }
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    return;
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  }
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  // otherwise, check with the linear solver
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1173850
  if (d_internal->postCheck(level))
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  {
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    // linear solver emitted a conflict or lemma, return
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35401
    return;
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  }
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1138449
  if (d_im.hasSent())
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  {
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    return;
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  }
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1138449
  if (Theory::fullEffort(level))
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  {
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40724
    d_arithModelCache.clear();
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    if (d_nonlinearExtension != nullptr)
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    {
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      std::set<Node> termSet;
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      updateModelCache(termSet);
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      d_nonlinearExtension->checkFullEffort(d_arithModelCache, termSet);
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    }
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17235
    else if (d_internal->foundNonlinear())
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    {
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      // set incomplete
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      d_im.setIncomplete(IncompleteId::ARITH_NL_DISABLED);
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    }
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  }
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}
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bool TheoryArith::preNotifyFact(
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    TNode atom, bool pol, TNode fact, bool isPrereg, bool isInternal)
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{
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  Trace("arith-check") << "TheoryArith::preNotifyFact: " << fact
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3463557
                       << ", isPrereg=" << isPrereg
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3463557
                       << ", isInternal=" << isInternal << std::endl;
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  // We do not assert to the equality engine of arithmetic in the standard way,
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  // hence we return "true" to indicate we are finished with this fact.
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3463557
  bool ret = true;
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3463557
  if (d_eqSolver != nullptr)
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  {
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    // the equality solver may indicate ret = false, after which the assertion
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    // will be asserted to the equality engine in the default way.
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    ret = d_eqSolver->preNotifyFact(atom, pol, fact, isPrereg, isInternal);
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  }
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  // we also always also notify the internal solver
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3463557
  d_internal->preNotifyFact(atom, pol, fact);
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3463557
  return ret;
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}
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bool TheoryArith::needsCheckLastEffort() {
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  if (d_nonlinearExtension != nullptr)
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  {
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    return d_nonlinearExtension->hasNlTerms();
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  }
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  return false;
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}
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TrustNode TheoryArith::explain(TNode n)
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{
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  if (d_eqSolver != nullptr)
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  {
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    // if the equality solver has an explanation for it, use it
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    TrustNode texp = d_eqSolver->explain(n);
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    if (!texp.isNull())
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    {
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      return texp;
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    }
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  }
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13682
  return d_internal->explain(n);
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}
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1864142
void TheoryArith::propagate(Effort e) {
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1864142
  d_internal->propagate(e);
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1864142
}
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bool TheoryArith::collectModelInfo(TheoryModel* m,
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                                   const std::set<Node>& termSet)
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{
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  // this overrides behavior to not assert equality engine
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11948
  return collectModelValues(m, termSet);
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}
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bool TheoryArith::collectModelValues(TheoryModel* m,
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                                     const std::set<Node>& termSet)
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{
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11948
  if (Trace.isOn("arith::model"))
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  {
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    Trace("arith::model") << "arithmetic model after pruning" << std::endl;
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    for (const auto& p : d_arithModelCache)
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    {
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      Trace("arith::model") << "\t" << p.first << " -> " << p.second << std::endl;
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    }
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  }
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  updateModelCache(termSet);
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  if (sanityCheckIntegerModel())
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  {
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    // We added a lemma
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    return false;
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  }
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  // We are now ready to assert the model.
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213747
  for (const std::pair<const Node, Node>& p : d_arithModelCache)
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  {
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201799
    if (termSet.find(p.first) == termSet.end())
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    {
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      continue;
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    }
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    // maps to constant of comparable type
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201797
    Assert(p.first.getType().isComparableTo(p.second.getType()));
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201797
    if (m->assertEquality(p.first, p.second, true))
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    {
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201797
      continue;
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    }
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    Assert(false) << "A model equality could not be asserted: " << p.first
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                        << " == " << p.second << std::endl;
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    // If we failed to assert an equality, it is likely due to theory
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    // combination, namely the repaired model for non-linear changed
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    // an equality status that was agreed upon by both (linear) arithmetic
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    // and another theory. In this case, we must add a lemma, or otherwise
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    // we would terminate with an invalid model. Thus, we add a splitting
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    // lemma of the form ( x = v V x != v ) where v is the model value
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    // assigned by the non-linear solver to x.
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    if (d_nonlinearExtension != nullptr)
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    {
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      Node eq = p.first.eqNode(p.second);
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      Node lem = NodeManager::currentNM()->mkNode(kind::OR, eq, eq.negate());
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      bool added = d_im.lemma(lem, InferenceId::ARITH_SPLIT_FOR_NL_MODEL);
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      AlwaysAssert(added) << "The lemma was already in cache. Probably there is something wrong with theory combination...";
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    }
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    return false;
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  }
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11948
  return true;
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}
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void TheoryArith::notifyRestart(){
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878
  d_internal->notifyRestart();
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878
}
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9354
void TheoryArith::presolve(){
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9354
  d_internal->presolve();
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9354
}
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386189
EqualityStatus TheoryArith::getEqualityStatus(TNode a, TNode b) {
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386189
  Debug("arith") << "TheoryArith::getEqualityStatus(" << a << ", " << b << ")" << std::endl;
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386189
  if (d_arithModelCache.empty())
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  {
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369739
    return d_internal->getEqualityStatus(a,b);
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  }
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32900
  Node aval = Rewriter::rewrite(a.substitute(d_arithModelCache.begin(), d_arithModelCache.end()));
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32900
  Node bval = Rewriter::rewrite(b.substitute(d_arithModelCache.begin(), d_arithModelCache.end()));
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16450
  if (aval == bval)
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  {
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5315
    return EQUALITY_TRUE_IN_MODEL;
336
  }
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11135
  return EQUALITY_FALSE_IN_MODEL;
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}
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2288
Node TheoryArith::getModelValue(TNode var) {
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2288
  return d_internal->getModelValue( var );
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}
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6721
std::pair<bool, Node> TheoryArith::entailmentCheck(TNode lit)
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{
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13442
  ArithEntailmentCheckParameters def;
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6721
  def.addLookupRowSumAlgorithms();
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13442
  ArithEntailmentCheckSideEffects ase;
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6721
  std::pair<bool, Node> res = d_internal->entailmentCheck(lit, def, ase);
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13442
  return res;
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}
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eq::ProofEqEngine* TheoryArith::getProofEqEngine()
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{
354
  return d_im.getProofEqEngine();
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}
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23489
void TheoryArith::updateModelCache(std::set<Node>& termSet)
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{
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23489
  if (d_arithModelCache.empty())
360
  {
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23489
    collectAssertedTerms(termSet);
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23489
    d_internal->collectModelValues(termSet, d_arithModelCache);
363
  }
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23489
}
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11948
void TheoryArith::updateModelCache(const std::set<Node>& termSet)
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{
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11948
  if (d_arithModelCache.empty())
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  {
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7532
    d_internal->collectModelValues(termSet, d_arithModelCache);
370
  }
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11948
}
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11948
bool TheoryArith::sanityCheckIntegerModel()
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{
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375
    // Double check that the model from the linear solver respects integer types,
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    // if it does not, add a branch and bound lemma. This typically should never
377
    // be necessary, but is needed in rare cases.
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11948
    bool addedLemma = false;
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11948
    bool badAssignment = false;
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11948
    Trace("arith-check") << "model:" << std::endl;
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213747
    for (const auto& p : d_arithModelCache)
382
    {
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201799
      Trace("arith-check") << p.first << " -> " << p.second << std::endl;
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201799
      if (p.first.getType().isInteger() && !p.second.getType().isInteger())
385
      {
386
        Assert(false) << "TheoryArithPrivate generated a bad model value for "
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                        "integer variable "
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                      << p.first << " : " << p.second;
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        // must branch and bound
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        TrustNode lem =
391
            d_bab.branchIntegerVariable(p.first, p.second.getConst<Rational>());
392
        if (d_im.trustedLemma(lem, InferenceId::ARITH_BB_LEMMA))
393
        {
394
          addedLemma = true;
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        }
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        badAssignment = true;
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      }
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    }
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11948
    if (addedLemma)
400
    {
401
      // we had to add a branch and bound lemma since the linear solver assigned
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      // a non-integer value to an integer variable.
403
      return true;
404
    }
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    // this would imply that linear arithmetic's model failed to satisfy a branch
406
    // and bound lemma
407
11948
    AlwaysAssert(!badAssignment)
408
        << "Bad assignment from TheoryArithPrivate::collectModelValues, and no "
409
          "branching lemma was sent";
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11948
    return false;
411
}
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}  // namespace arith
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}  // namespace theory
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22746
}  // namespace cvc5