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/********************* */
/*! \file variable_ordering.cpp
** \verbatim
** Top contributors (to current version):
** Gereon Kremer
** 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 Implements variable orderings tailored to CAD.
**
** Implements variable orderings tailored to CAD.
**/
#include "theory/arith/nl/cad/variable_ordering.h"
#ifdef CVC4_POLY_IMP
#include "util/poly_util.h"
namespace CVC4 {
namespace theory {
namespace arith {
namespace nl {
namespace cad {
std::vector<poly_utils::VariableInformation> collectInformation(
const Constraints::ConstraintVector& polys, bool with_totals)
{
poly::VariableCollector vc;
for (const auto& c : polys)
{
vc(std::get<0>(c));
}
std::vector<poly_utils::VariableInformation> res;
for (const auto& v : vc.get_variables())
{
res.emplace_back();
res.back().var = v;
for (const auto& c : polys)
{
poly_utils::getVariableInformation(res.back(), std::get<0>(c));
}
}
if (with_totals)
{
res.emplace_back();
for (const auto& c : polys)
{
poly_utils::getVariableInformation(res.back(), std::get<0>(c));
}
}
return res;
}
std::vector<poly::Variable> getVariables(
const std::vector<poly_utils::VariableInformation>& vi)
{
std::vector<poly::Variable> res;
for (const auto& v : vi)
{
res.emplace_back(v.var);
}
return res;
}
std::vector<poly::Variable> sortByid(const Constraints::ConstraintVector& polys)
{
auto vi = collectInformation(polys);
std::sort(
vi.begin(),
vi.end(),
[](const poly_utils::VariableInformation& a,
const poly_utils::VariableInformation& b) { return a.var < b.var; });
return getVariables(vi);
};
std::vector<poly::Variable> sortBrown(
const Constraints::ConstraintVector& polys)
{
auto vi = collectInformation(polys);
std::sort(vi.begin(),
vi.end(),
[](const poly_utils::VariableInformation& a,
const poly_utils::VariableInformation& b) {
if (a.max_degree != b.max_degree)
return a.max_degree > b.max_degree;
if (a.max_terms_tdegree != b.max_terms_tdegree)
return a.max_terms_tdegree > b.max_terms_tdegree;
return a.num_terms > b.num_terms;
});
return getVariables(vi);
};
std::vector<poly::Variable> sortTriangular(
const Constraints::ConstraintVector& polys)
{
auto vi = collectInformation(polys);
std::sort(vi.begin(),
vi.end(),
[](const poly_utils::VariableInformation& a,
const poly_utils::VariableInformation& b) {
if (a.max_degree != b.max_degree)
return a.max_degree > b.max_degree;
if (a.max_lc_degree != b.max_lc_degree)
return a.max_lc_degree > b.max_lc_degree;
return a.sum_poly_degree > b.sum_poly_degree;
});
return getVariables(vi);
};
VariableOrdering::VariableOrdering() {}
VariableOrdering::~VariableOrdering() {}
std::vector<poly::Variable> VariableOrdering::operator()(
const Constraints::ConstraintVector& polys,
VariableOrderingStrategy vos) const
{
switch (vos)
{
case VariableOrderingStrategy::BYID: return sortByid(polys);
case VariableOrderingStrategy::BROWN: return sortBrown(polys);
case VariableOrderingStrategy::TRIANGULAR: return sortTriangular(polys);
default: Assert(false) << "Unsupported variable ordering.";
}
return {};
}
} // namespace cad
} // namespace nl
} // namespace arith
} // namespace theory
} // namespace CVC4
#endif
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