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[ModelBuilder] big update on the code; remove hash table, use c++ canonicalization of linear expressions; remove code duplication

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This commit is contained in:
Laurent Perron
2023-07-27 08:50:52 -07:00
parent 6d8495f423
commit 5b8cdcd6bf
4 changed files with 359 additions and 322 deletions
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34
ortools/linear_solver/python/model_builder_helper.cc
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@@ -121,7 +121,7 @@ void BuildModelFromSparseData(
}
std::vector<std::pair<int, double>> SortedGroupedTerms(
const std::vector<int>& indices, const std::vector<double>& coefficients) {
absl::Span<const int> indices, absl::Span<const double> coefficients) {
CHECK_EQ(indices.size(), coefficients.size());
std::vector<std::pair<int, double>> terms;
terms.reserve(indices.size());
@@ -139,14 +139,15 @@ std::vector<std::pair<int, double>> SortedGroupedTerms(
});
int pos = 0;
for (int i = 0; i < terms.size(); ++i) {
if (i == 0 || terms[i].first != terms[i - 1].first) {
if (i != pos) {
terms[pos] = terms[i];
}
pos++;
} else {
terms[pos].second += terms[i].second;
const int var = terms[i].first;
double coeff = terms[i].second;
while (i + 1 < terms.size() && terms[i + 1].first == var) {
coeff += terms[i + 1].second;
++i;
}
if (coeff == 0.0) continue;
terms[pos] = {var, coeff};
++pos;
}
terms.resize(pos);
return terms;
@@ -341,7 +342,22 @@ PYBIND11_MODULE(model_builder_helper, m) {
.def("set_maximize", &ModelBuilderHelper::SetMaximize, arg("maximize"))
.def("set_objective_offset", &ModelBuilderHelper::SetObjectiveOffset,
arg("offset"))
.def("objective_offset", &ModelBuilderHelper::ObjectiveOffset);
.def("objective_offset", &ModelBuilderHelper::ObjectiveOffset)
.def("sort_and_regroup_terms",
[](ModelBuilderHelper* helper, py::array_t<int> indices,
py::array_t<double> coefficients) {
const std::vector<std::pair<int, double>> terms =
SortedGroupedTerms(indices, coefficients);
std::vector<int> sorted_indices;
std::vector<double> sorted_coefficients;
sorted_indices.reserve(terms.size());
sorted_coefficients.reserve(terms.size());
for (const auto& [i, c] : terms) {
sorted_indices.push_back(i);
sorted_coefficients.push_back(c);
}
return std::make_pair(sorted_indices, sorted_coefficients);
});
py::enum_<SolveStatus>(m, "SolveStatus")
.value("OPTIMAL", SolveStatus::OPTIMAL)