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/********************* */
/*! \file lazy_proof.h
** \verbatim
** Top contributors (to current version):
** Andrew Reynolds
** This file is part of the CVC4 project.
** Copyright (c) 2009-2019 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 Lazy proof utility
**/
#include "expr/lazy_proof.h"
using namespace CVC4::kind;
namespace CVC4 {
LazyCDProof::LazyCDProof(ProofNodeManager* pnm,
ProofGenerator* dpg,
context::Context* c)
: CDProof(pnm, c), d_gens(c ? c : &d_context), d_defaultGen(dpg)
{
}
LazyCDProof::~LazyCDProof() {}
std::shared_ptr<ProofNode> LazyCDProof::mkProof(Node fact)
{
Trace("lazy-cdproof") << "LazyCDProof::mkLazyProof " << fact << std::endl;
// make the proof, which should always be non-null, since we construct an
// assumption in the worst case.
std::shared_ptr<ProofNode> opf = CDProof::mkProof(fact);
Assert(opf != nullptr);
if (!hasGenerators())
{
Trace("lazy-cdproof") << "...no generators, finished" << std::endl;
// optimization: no generators, we are done
return opf;
}
// otherwise, we traverse the proof opf and fill in the ASSUME leafs that
// have generators
std::unordered_set<ProofNode*> visited;
std::unordered_set<ProofNode*>::iterator it;
std::vector<ProofNode*> visit;
ProofNode* cur;
visit.push_back(opf.get());
do
{
cur = visit.back();
visit.pop_back();
it = visited.find(cur);
if (it == visited.end())
{
visited.insert(cur);
if (cur->getRule() == PfRule::ASSUME)
{
Node afact = cur->getResult();
bool isSym = false;
ProofGenerator* pg = getGeneratorFor(afact, isSym);
if (pg != nullptr)
{
Trace("lazy-cdproof") << "LazyCDProof: Call generator for assumption "
<< afact << std::endl;
Assert(!isSym || afact.getKind() == EQUAL);
Node afactGen = isSym ? afact[1].eqNode(afact[0]) : afact;
// use the addProofTo interface
if (!pg->addProofTo(afactGen, this))
{
Trace("lazy-cdproof") << "LazyCDProof: Failed added fact for "
<< afactGen << std::endl;
Assert(false) << "Proof generator " << pg->identify()
<< " could not add proof for fact " << afactGen
<< std::endl;
}
else
{
Trace("lazy-cdproof") << "LazyCDProof: Successfully added fact for "
<< afactGen << std::endl;
}
}
else
{
Trace("lazy-cdproof")
<< "LazyCDProof: No generator for " << afact << std::endl;
}
// Notice that we do not traverse the proofs that have been generated
// lazily by the proof generators here. In other words, we assume that
// the proofs from provided proof generators are "complete" and need
// no further modification by this class.
}
else
{
const std::vector<std::shared_ptr<ProofNode>>& cc = cur->getChildren();
for (const std::shared_ptr<ProofNode>& cp : cc)
{
visit.push_back(cp.get());
}
}
}
} while (!visit.empty());
// we have now updated the ASSUME leafs of opf, return it
Trace("lazy-cdproof") << "...finished" << std::endl;
return opf;
}
void LazyCDProof::addLazyStep(Node expected,
ProofGenerator* pg,
bool forceOverwrite)
{
Assert(pg != nullptr);
NodeProofGeneratorMap::const_iterator it = d_gens.find(expected);
if (it != d_gens.end() && !forceOverwrite)
{
// don't overwrite something that is already there
return;
}
// just store now
d_gens.insert(expected, pg);
if (forceOverwrite)
{
// TODO: if we stored expected via a normal call to CDProof::addStep, then
// we should overwrite the step in d_nodes with an ASSUME?
}
}
ProofGenerator* LazyCDProof::getGeneratorFor(Node fact, bool& isSym)
{
isSym = false;
NodeProofGeneratorMap::const_iterator it = d_gens.find(fact);
if (it != d_gens.end())
{
return (*it).second;
}
// could be symmetry
if (fact.getKind() != EQUAL || fact[0] == fact[1])
{
// can't be symmetry, return the default generator
return d_defaultGen;
}
Node factSym = fact[1].eqNode(fact[0]);
it = d_gens.find(factSym);
if (it != d_gens.end())
{
isSym = true;
return (*it).second;
}
// return the default generator
return d_defaultGen;
}
bool LazyCDProof::hasGenerators() const
{
return !d_gens.empty() || d_defaultGen != nullptr;
}
} // namespace CVC4
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