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| 1 | +// Copyright 2010-2024 Google LLC |
| 2 | +// Licensed under the Apache License, Version 2.0 (the "License"); |
| 3 | +// you may not use this file except in compliance with the License. |
| 4 | +// You may obtain a copy of the License at |
| 5 | +// |
| 6 | +// http://www.apache.org/licenses/LICENSE-2.0 |
| 7 | +// |
| 8 | +// Unless required by applicable law or agreed to in writing, software |
| 9 | +// distributed under the License is distributed on an "AS IS" BASIS, |
| 10 | +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 11 | +// See the License for the specific language governing permissions and |
| 12 | +// limitations under the License. |
| 13 | + |
| 14 | +// A pybind11 wrapper for set_cover_*. |
| 15 | + |
| 16 | +#include <memory> |
| 17 | + |
| 18 | +#include "absl/base/nullability.h" |
| 19 | +#include "ortools/algorithms/set_cover_heuristics.h" |
| 20 | +#include "ortools/algorithms/set_cover_invariant.h" |
| 21 | +#include "ortools/algorithms/set_cover_model.h" |
| 22 | +#include "ortools/algorithms/set_cover_reader.h" |
| 23 | +#include "pybind11/pybind11.h" |
| 24 | +#include "pybind11/pytypes.h" |
| 25 | +#include "pybind11/stl.h" |
| 26 | +#include "pybind11_protobuf/native_proto_caster.h" |
| 27 | + |
| 28 | +using ::operations_research::ElementDegreeSolutionGenerator; |
| 29 | +using ::operations_research::GreedySolutionGenerator; |
| 30 | +using ::operations_research::GuidedLocalSearch; |
| 31 | +using ::operations_research::Preprocessor; |
| 32 | +using ::operations_research::RandomSolutionGenerator; |
| 33 | +using ::operations_research::ReadBeasleySetCoverProblem; |
| 34 | +using ::operations_research::ReadRailSetCoverProblem; |
| 35 | +using ::operations_research::SetCoverInvariant; |
| 36 | +using ::operations_research::SetCoverModel; |
| 37 | +using ::operations_research::SteepestSearch; |
| 38 | +using ::operations_research::SubsetIndex; |
| 39 | +using ::operations_research::TrivialSolutionGenerator; |
| 40 | + |
| 41 | +namespace py = pybind11; |
| 42 | +using ::py::arg; |
| 43 | + |
| 44 | +// General note about TODOs: the corresponding functions/classes/methods are |
| 45 | +// more complex to wrap, as they use nonstandard types, and are less important, |
| 46 | +// as they are not as useful to most users (mostly useful to write some custom |
| 47 | +// Python heuristics). |
| 48 | + |
| 49 | +PYBIND11_MODULE(set_cover, m) { |
| 50 | + pybind11_protobuf::ImportNativeProtoCasters(); |
| 51 | + |
| 52 | + // set_cover_model.h |
| 53 | + py::class_<SetCoverModel>(m, "SetCoverModel") |
| 54 | + .def(py::init<>()) |
| 55 | + .def_property_readonly("num_elements", &SetCoverModel::num_elements) |
| 56 | + .def_property_readonly("num_subsets", &SetCoverModel::num_subsets) |
| 57 | + .def_property_readonly("num_nonzeros", &SetCoverModel::num_nonzeros) |
| 58 | + .def_property_readonly("fill_rate", &SetCoverModel::FillRate) |
| 59 | + .def("add_empty_subset", &SetCoverModel::AddEmptySubset, arg("cost")) |
| 60 | + .def( |
| 61 | + "add_element_to_last_subset", |
| 62 | + [](SetCoverModel& model, int element) { |
| 63 | + model.AddElementToLastSubset(element); |
| 64 | + }, |
| 65 | + arg("element")) |
| 66 | + .def( |
| 67 | + "set_subset_cost", |
| 68 | + [](SetCoverModel& model, int subset, double cost) { |
| 69 | + model.SetSubsetCost(subset, cost); |
| 70 | + }, |
| 71 | + arg("subset"), arg("cost")) |
| 72 | + .def( |
| 73 | + "add_element_to_subset", |
| 74 | + [](SetCoverModel& model, int element, int subset) { |
| 75 | + model.AddElementToSubset(element, subset); |
| 76 | + }, |
| 77 | + arg("subset"), arg("cost")) |
| 78 | + .def("compute_feasibility", &SetCoverModel::ComputeFeasibility) |
| 79 | + .def( |
| 80 | + "reserve_num_subsets", |
| 81 | + [](SetCoverModel& model, int num_subsets) { |
| 82 | + model.ReserveNumSubsets(num_subsets); |
| 83 | + }, |
| 84 | + arg("num_subsets")) |
| 85 | + .def( |
| 86 | + "reserve_num_elements_in_subset", |
| 87 | + [](SetCoverModel& model, int num_elements, int subset) { |
| 88 | + model.ReserveNumElementsInSubset(num_elements, subset); |
| 89 | + }, |
| 90 | + arg("num_elements"), arg("subset")) |
| 91 | + .def("export_model_as_proto", &SetCoverModel::ExportModelAsProto) |
| 92 | + .def("import_model_from_proto", &SetCoverModel::ImportModelFromProto); |
| 93 | + // TODO(user): add support for subset_costs, columns, rows, |
| 94 | + // row_view_is_valid, SubsetRange, ElementRange, all_subsets, |
| 95 | + // CreateSparseRowView, ComputeCostStats, ComputeRowStats, |
| 96 | + // ComputeColumnStats, ComputeRowDeciles, ComputeColumnDeciles. |
| 97 | + |
| 98 | + // TODO(user): wrap IntersectingSubsetsIterator. |
| 99 | + |
| 100 | + // set_cover_invariant.h |
| 101 | + py::class_<SetCoverInvariant>(m, "SetCoverInvariant") |
| 102 | + .def(py::init<SetCoverModel*>()) |
| 103 | + .def("initialize", &SetCoverInvariant::Initialize) |
| 104 | + .def("clear", &SetCoverInvariant::Clear) |
| 105 | + .def("recompute_invariant", &SetCoverInvariant::RecomputeInvariant) |
| 106 | + .def("model", &SetCoverInvariant::model) |
| 107 | + .def_property( |
| 108 | + "model", |
| 109 | + // Expected semantics: give a pointer to Python **while |
| 110 | + // keeping ownership** in C++. |
| 111 | + [](SetCoverInvariant& invariant) -> std::shared_ptr<SetCoverModel> { |
| 112 | + // https://pybind11.readthedocs.io/en/stable/advanced/smart_ptrs.html#std-shared-ptr |
| 113 | + std::shared_ptr<SetCoverModel> ptr(invariant.model()); |
| 114 | + return ptr; |
| 115 | + }, |
| 116 | + [](SetCoverInvariant& invariant, const SetCoverModel& model) { |
| 117 | + *invariant.model() = model; |
| 118 | + }) |
| 119 | + .def("cost", &SetCoverInvariant::cost) |
| 120 | + .def("num_uncovered_elements", &SetCoverInvariant::num_uncovered_elements) |
| 121 | + .def("clear_trace", &SetCoverInvariant::ClearTrace) |
| 122 | + .def("clear_removability_information", |
| 123 | + &SetCoverInvariant::ClearRemovabilityInformation) |
| 124 | + .def("compress_trace", &SetCoverInvariant::CompressTrace) |
| 125 | + .def("check_consistency", &SetCoverInvariant::CheckConsistency) |
| 126 | + .def( |
| 127 | + "flip", |
| 128 | + [](SetCoverInvariant& invariant, int subset) { |
| 129 | + invariant.Flip(SubsetIndex(subset)); |
| 130 | + }, |
| 131 | + arg("subset")) |
| 132 | + .def( |
| 133 | + "flip_and_fully_update", |
| 134 | + [](SetCoverInvariant& invariant, int subset) { |
| 135 | + invariant.FlipAndFullyUpdate(SubsetIndex(subset)); |
| 136 | + }, |
| 137 | + arg("subset")) |
| 138 | + .def( |
| 139 | + "select", |
| 140 | + [](SetCoverInvariant& invariant, int subset) { |
| 141 | + invariant.Select(SubsetIndex(subset)); |
| 142 | + }, |
| 143 | + arg("subset")) |
| 144 | + .def( |
| 145 | + "select_and_fully_update", |
| 146 | + [](SetCoverInvariant& invariant, int subset) { |
| 147 | + invariant.SelectAndFullyUpdate(SubsetIndex(subset)); |
| 148 | + }, |
| 149 | + arg("subset")) |
| 150 | + .def( |
| 151 | + "deselect", |
| 152 | + [](SetCoverInvariant& invariant, int subset) { |
| 153 | + invariant.Deselect(SubsetIndex(subset)); |
| 154 | + }, |
| 155 | + arg("subset")) |
| 156 | + .def( |
| 157 | + "deselect_and_fully_update", |
| 158 | + [](SetCoverInvariant& invariant, int subset) { |
| 159 | + invariant.DeselectAndFullyUpdate(SubsetIndex(subset)); |
| 160 | + }, |
| 161 | + arg("subset")) |
| 162 | + .def("export_solution_as_proto", |
| 163 | + &SetCoverInvariant::ExportSolutionAsProto) |
| 164 | + .def("import_solution_from_proto", |
| 165 | + &SetCoverInvariant::ImportSolutionFromProto); |
| 166 | + // TODO(user): add support for is_selected, num_free_elements, |
| 167 | + // num_coverage_le_1_elements, coverage, ComputeCoverageInFocus, |
| 168 | + // is_redundant, trace, new_removable_subsets, new_non_removable_subsets, |
| 169 | + // LoadSolution, ComputeIsRedundant. |
| 170 | + |
| 171 | + // set_cover_heuristics.h |
| 172 | + py::class_<Preprocessor>(m, "Preprocessor") |
| 173 | + . def(py::init<absl::Nonnull<SetCoverInvariant*>>()) |
| 174 | + .def("next_solution", |
| 175 | + [](Preprocessor& heuristic) -> bool { |
| 176 | + return heuristic.NextSolution(); |
| 177 | + }) |
| 178 | + .def("num_columns_fixed_by_singleton_row", |
| 179 | + &Preprocessor::num_columns_fixed_by_singleton_row); |
| 180 | + // TODO(user): add support for focus argument. |
| 181 | + |
| 182 | + py::class_<TrivialSolutionGenerator>(m, "TrivialSolutionGenerator") |
| 183 | + .def(py::init<SetCoverInvariant*>()) |
| 184 | + .def("next_solution", [](TrivialSolutionGenerator& heuristic) -> bool { |
| 185 | + return heuristic.NextSolution(); |
| 186 | + }); |
| 187 | + // TODO(user): add support for focus argument. |
| 188 | + |
| 189 | + py::class_<RandomSolutionGenerator>(m, "RandomSolutionGenerator") |
| 190 | + .def(py::init<SetCoverInvariant*>()) |
| 191 | + .def("next_solution", [](RandomSolutionGenerator& heuristic) -> bool { |
| 192 | + return heuristic.NextSolution(); |
| 193 | + }); |
| 194 | + // TODO(user): add support for focus argument. |
| 195 | + |
| 196 | + py::class_<GreedySolutionGenerator>(m, "GreedySolutionGenerator") |
| 197 | + .def(py::init<SetCoverInvariant*>()) |
| 198 | + .def("next_solution", [](GreedySolutionGenerator& heuristic) -> bool { |
| 199 | + return heuristic.NextSolution(); |
| 200 | + }); |
| 201 | + // TODO(user): add support for focus and cost arguments. |
| 202 | + |
| 203 | + py::class_<ElementDegreeSolutionGenerator>(m, |
| 204 | + "ElementDegreeSolutionGenerator") |
| 205 | + .def(py::init<SetCoverInvariant*>()) |
| 206 | + .def("next_solution", |
| 207 | + [](ElementDegreeSolutionGenerator& heuristic) -> bool { |
| 208 | + return heuristic.NextSolution(); |
| 209 | + }); |
| 210 | + // TODO(user): add support for focus and cost arguments. |
| 211 | + |
| 212 | + py::class_<SteepestSearch>(m, "SteepestSearch") |
| 213 | + .def(py::init<SetCoverInvariant*>()) |
| 214 | + .def("next_solution", |
| 215 | + [](SteepestSearch& heuristic, int num_iterations) -> bool { |
| 216 | + return heuristic.NextSolution(num_iterations); |
| 217 | + }); |
| 218 | + // TODO(user): add support for focus and cost arguments. |
| 219 | + |
| 220 | + py::class_<GuidedLocalSearch>(m, "GuidedLocalSearch") |
| 221 | + .def(py::init<SetCoverInvariant*>()) |
| 222 | + .def("initialize", &GuidedLocalSearch::Initialize) |
| 223 | + .def("next_solution", |
| 224 | + [](GuidedLocalSearch& heuristic, int num_iterations) -> bool { |
| 225 | + return heuristic.NextSolution(num_iterations); |
| 226 | + }); |
| 227 | + // TODO(user): add support for focus and cost arguments. |
| 228 | + |
| 229 | + // TODO(user): add support for ClearRandomSubsets, ClearRandomSubsets, |
| 230 | + // ClearMostCoveredElements, ClearMostCoveredElements, TabuList, |
| 231 | + // GuidedTabuSearch. |
| 232 | + |
| 233 | + // set_cover_reader.h |
| 234 | + m.def("read_beasly_set_cover_problem", &ReadBeasleySetCoverProblem); |
| 235 | + m.def("read_rail_set_cover_problem", &ReadRailSetCoverProblem); |
| 236 | + |
| 237 | + // set_cover_lagrangian.h |
| 238 | + // TODO(user): add support for SetCoverLagrangian. |
| 239 | +} |
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