2025-01-10 11:33:35 +01:00
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// Copyright 2010-2025 Google LLC
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2011-11-03 10:27:53 +00:00
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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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2014-07-09 15:18:27 +00:00
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2011-11-03 10:27:53 +00:00
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// Integer programming example that shows how to use the API.
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2025-02-21 15:14:38 +01:00
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#include <cstdlib>
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2025-12-12 09:33:50 +01:00
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#include <memory>
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2022-09-09 16:49:24 +02:00
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#include <string>
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#include <vector>
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2025-02-19 17:00:34 +01:00
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#include "absl/log/globals.h"
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2025-02-27 09:38:35 +01:00
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#include "absl/log/log.h"
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2021-01-14 10:48:19 +01:00
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#include "absl/strings/match.h"
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#include "absl/strings/string_view.h"
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2022-02-25 09:47:52 +01:00
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#include "ortools/base/init_google.h"
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2026-02-20 16:40:19 +01:00
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#include "ortools/base/log_severity.h"
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2017-04-26 17:30:25 +02:00
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#include "ortools/linear_solver/linear_solver.h"
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2011-11-03 10:27:53 +00:00
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namespace operations_research {
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2025-12-12 09:33:50 +01:00
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void RunIntegerProgrammingExample(const std::string& solver_id) {
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2020-08-18 17:16:10 +02:00
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LOG(INFO) << "---- Integer programming example with " << solver_id << " ----";
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2020-06-24 19:04:13 +02:00
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2025-12-12 09:33:50 +01:00
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std::unique_ptr<MPSolver> solver(MPSolver::CreateSolver(solver_id));
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if (!solver) {
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LOG(INFO) << "Unable to create solver : " << solver_id;
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2020-06-25 10:33:13 +02:00
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return;
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}
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2025-12-12 09:33:50 +01:00
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const double infinity = solver->infinity();
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2018-11-22 13:15:13 +01:00
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// x and y are integer non-negative variables.
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2025-12-12 09:33:50 +01:00
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MPVariable* const x = solver->MakeIntVar(0.0, infinity, "x");
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MPVariable* const y = solver->MakeIntVar(0.0, infinity, "y");
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2011-11-03 10:27:53 +00:00
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2018-11-22 13:15:13 +01:00
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// Maximize x + 10 * y.
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2025-12-12 09:33:50 +01:00
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MPObjective* const objective = solver->MutableObjective();
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2018-11-22 13:15:13 +01:00
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objective->SetCoefficient(x, 1);
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objective->SetCoefficient(y, 10);
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objective->SetMaximization();
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2011-11-03 10:27:53 +00:00
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2018-11-22 13:15:13 +01:00
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// x + 7 * y <= 17.5.
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2025-12-12 09:33:50 +01:00
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MPConstraint* const c0 = solver->MakeRowConstraint(-infinity, 17.5);
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2018-11-22 13:15:13 +01:00
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c0->SetCoefficient(x, 1);
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c0->SetCoefficient(y, 7);
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2011-11-03 10:27:53 +00:00
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2018-11-22 13:15:13 +01:00
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// x <= 3.5
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2025-12-12 09:33:50 +01:00
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MPConstraint* const c1 = solver->MakeRowConstraint(-infinity, 3.5);
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2018-11-22 13:15:13 +01:00
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c1->SetCoefficient(x, 1);
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c1->SetCoefficient(y, 0);
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2011-11-03 10:27:53 +00:00
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2025-12-12 09:33:50 +01:00
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LOG(INFO) << "Number of variables = " << solver->NumVariables();
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LOG(INFO) << "Number of constraints = " << solver->NumConstraints();
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2011-11-03 10:27:53 +00:00
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2025-12-12 09:33:50 +01:00
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const MPSolver::ResultStatus result_status = solver->Solve();
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2018-11-22 13:15:13 +01:00
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// Check that the problem has an optimal solution.
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if (result_status != MPSolver::OPTIMAL) {
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LOG(FATAL) << "The problem does not have an optimal solution!";
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2018-09-26 11:02:04 +02:00
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}
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2018-11-22 13:15:13 +01:00
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LOG(INFO) << "Solution:";
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LOG(INFO) << "x = " << x->solution_value();
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LOG(INFO) << "y = " << y->solution_value();
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LOG(INFO) << "Optimal objective value = " << objective->Value();
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LOG(INFO) << "";
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LOG(INFO) << "Advanced usage:";
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2025-12-12 09:33:50 +01:00
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LOG(INFO) << "Problem solved in " << solver->wall_time() << " milliseconds";
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LOG(INFO) << "Problem solved in " << solver->iterations() << " iterations";
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LOG(INFO) << "Problem solved in " << solver->nodes()
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2018-11-22 13:15:13 +01:00
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<< " branch-and-bound nodes";
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}
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2011-11-03 10:27:53 +00:00
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2018-11-22 13:15:13 +01:00
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void RunAllExamples() {
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2025-12-12 09:33:50 +01:00
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std::vector<MPSolver::OptimizationProblemType> supported_problem_types =
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MPSolverInterfaceFactoryRepository::GetInstance()
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->ListAllRegisteredProblemTypes();
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for (MPSolver::OptimizationProblemType type : supported_problem_types) {
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const std::string type_name = MPModelRequest::SolverType_Name(
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static_cast<MPModelRequest::SolverType>(type));
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if (!SolverTypeIsMip(type)) continue;
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if (absl::StrContains(type_name, "KNAPSACK")) continue;
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if (absl::StrContains(type_name, "BOP")) continue;
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if (absl::StrContains(type_name, "HIGHS")) continue;
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// ASAN issues a warning in CBC code which cannot be avoided for now:
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// AddressSanitizer: float-cast-overflow
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// third_party/cbc/Cgl/src/CglPreProcess/CglPreProcess.cpp:1717:36
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#ifdef ADDRESS_SANITIZER
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if (type_name.find("CBC") != std::string::npos) {
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continue;
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}
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#endif
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RunIntegerProgrammingExample(type_name);
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}
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2018-11-22 13:15:13 +01:00
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}
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2020-10-22 23:36:58 +02:00
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} // namespace operations_research
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2011-11-03 10:27:53 +00:00
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2020-10-29 14:25:39 +01:00
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int main(int argc, char** argv) {
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2025-02-19 17:00:34 +01:00
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absl::SetStderrThreshold(absl::LogSeverityAtLeast::kInfo);
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2023-06-21 17:31:06 +02:00
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InitGoogle(argv[0], &argc, &argv, true);
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2011-11-03 10:27:53 +00:00
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operations_research::RunAllExamples();
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2021-01-14 10:48:19 +01:00
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return EXIT_SUCCESS;
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2011-11-03 10:27:53 +00:00
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}
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