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/******************************************************************************
* Top contributors (to current version):
* Andrew Reynolds
*
* This file is part of the cvc5 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.
* ****************************************************************************
*
* Utilities for computing letification of proofs.
*/
#include "proof/proof_letify.h"
namespace cvc5 {
namespace proof {
bool ProofLetifyTraverseCallback::shouldTraverse(const ProofNode* pn)
{
return pn->getRule() != PfRule::SCOPE;
}
void ProofLetify::computeProofLet(const ProofNode* pn,
std::vector<const ProofNode*>& pletList,
std::map<const ProofNode*, size_t>& pletMap,
size_t thresh,
ProofLetifyTraverseCallback* pltc)
{
Assert(pletList.empty() && pletMap.empty());
if (thresh == 0)
{
// value of 0 means do not introduce let
return;
}
std::vector<const ProofNode*> visitList;
std::map<const ProofNode*, size_t> pcount;
if (pltc == nullptr)
{
// use default callback
ProofLetifyTraverseCallback defaultPltc;
computeProofCounts(pn, visitList, pcount, &defaultPltc);
}
else
{
computeProofCounts(pn, visitList, pcount, pltc);
}
// Now populate the pletList and pletMap
convertProofCountToLet(visitList, pcount, pletList, pletMap, thresh);
}
void ProofLetify::computeProofCounts(const ProofNode* pn,
std::vector<const ProofNode*>& visitList,
std::map<const ProofNode*, size_t>& pcount,
ProofLetifyTraverseCallback* pltc)
{
std::map<const ProofNode*, size_t>::iterator it;
std::vector<const ProofNode*> visit;
const ProofNode* cur;
visit.push_back(pn);
do
{
cur = visit.back();
it = pcount.find(cur);
if (it == pcount.end())
{
pcount[cur] = 0;
if (!pltc->shouldTraverse(cur))
{
// callback indicated we should not traverse
continue;
}
const std::vector<std::shared_ptr<ProofNode>>& pc = cur->getChildren();
for (const std::shared_ptr<ProofNode>& cp : pc)
{
visit.push_back(cp.get());
}
}
else
{
if (it->second == 0)
{
visitList.push_back(cur);
}
pcount[cur]++;
visit.pop_back();
}
} while (!visit.empty());
}
void ProofLetify::convertProofCountToLet(
const std::vector<const ProofNode*>& visitList,
const std::map<const ProofNode*, size_t>& pcount,
std::vector<const ProofNode*>& pletList,
std::map<const ProofNode*, size_t>& pletMap,
size_t thresh)
{
Assert(pletList.empty() && pletMap.empty());
if (thresh == 0)
{
// value of 0 means do not introduce let
return;
}
// Assign ids for those whose count is > 1, traverse in reverse order
// so that deeper proofs are assigned lower identifiers
std::map<const ProofNode*, size_t>::const_iterator itc;
for (const ProofNode* pn : visitList)
{
itc = pcount.find(pn);
Assert(itc != pcount.end());
if (itc->second >= thresh && pn->getRule() != PfRule::ASSUME)
{
pletList.push_back(pn);
// start with id 1
size_t id = pletMap.size() + 1;
pletMap[pn] = id;
}
}
}
} // namespace proof
} // namespace cvc5
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