4f381f6d07
* bump abseil to 20250814 * bump protobuf to v32.0 * cmake: add ccache auto support * backport flatzinc, math_opt and sat update
107 lines
4.0 KiB
C++
107 lines
4.0 KiB
C++
// Copyright 2010-2025 Google LLC
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "ortools/sat/combine_solutions.h"
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#include <cstdint>
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#include <memory>
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#include <optional>
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#include <string>
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#include <string_view>
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#include <vector>
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#include "absl/log/check.h"
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#include "absl/strings/str_cat.h"
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#include "absl/strings/string_view.h"
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#include "absl/types/span.h"
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#include "ortools/sat/cp_model_checker.h"
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#include "ortools/sat/model.h"
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#include "ortools/sat/synchronization.h"
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namespace operations_research {
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namespace sat {
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bool TrySolution(const CpModelProto& model, absl::Span<const int64_t> solution,
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absl::Span<const int64_t> new_solution,
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absl::Span<const int64_t> base_solution,
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std::vector<int64_t>* new_combined_solution) {
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new_combined_solution->resize(new_solution.size());
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for (int i = 0; i < new_solution.size(); ++i) {
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if (new_solution[i] != base_solution[i]) {
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// A value that changed that we patch.
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(*new_combined_solution)[i] = new_solution[i];
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} else {
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(*new_combined_solution)[i] = solution[i];
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}
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}
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return SolutionIsFeasible(model, *new_combined_solution);
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}
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std::optional<std::vector<int64_t>> FindCombinedSolution(
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const CpModelProto& model, absl::Span<const int64_t> new_solution,
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absl::Span<const int64_t> base_solution,
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const SharedResponseManager* response_manager, std::string* solution_info) {
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CHECK_EQ(new_solution.size(), base_solution.size());
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const std::vector<
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std::shared_ptr<const SharedSolutionRepository<int64_t>::Solution>>
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solutions =
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response_manager->SolutionPool().BestSolutions().GetBestNSolutions(
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10);
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for (int sol_idx = 0; sol_idx < solutions.size(); ++sol_idx) {
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std::shared_ptr<const SharedSolutionRepository<int64_t>::Solution> s =
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solutions[sol_idx];
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DCHECK_EQ(s->variable_values.size(), new_solution.size());
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if (s->variable_values == new_solution ||
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s->variable_values == base_solution) {
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continue;
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}
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std::vector<int64_t> new_combined_solution;
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if (TrySolution(model, s->variable_values, new_solution, base_solution,
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&new_combined_solution)) {
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absl::StrAppend(solution_info, " [combined with: ",
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std::string_view(solutions[sol_idx]->info).substr(0, 20),
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"...]");
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return new_combined_solution;
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}
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}
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return std::nullopt;
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}
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PushedSolutionPointers PushAndMaybeCombineSolution(
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SharedResponseManager* response_manager, const CpModelProto& model_proto,
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absl::Span<const int64_t> new_solution, absl::string_view solution_info,
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std::shared_ptr<const SharedSolutionRepository<int64_t>::Solution>
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base_solution) {
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PushedSolutionPointers result = {nullptr, nullptr};
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result.pushed_solution = response_manager->NewSolution(
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new_solution, solution_info, nullptr,
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base_solution == nullptr ? -1 : base_solution->source_id);
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if (base_solution != nullptr) {
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std::string combined_solution_info(solution_info);
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std::optional<std::vector<int64_t>> combined_solution =
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FindCombinedSolution(model_proto, new_solution,
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base_solution->variable_values, response_manager,
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&combined_solution_info);
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if (combined_solution.has_value()) {
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result.improved_solution = response_manager->NewSolution(
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combined_solution.value(), combined_solution_info);
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}
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}
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return result;
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}
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} // namespace sat
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} // namespace operations_research
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