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integer_programming.cc
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109 lines (96 loc) · 3.99 KB
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// Copyright 2010-2025 Google LLC
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Integer programming example that shows how to use the API.
#include <cstdlib>
#include <memory>
#include <string>
#include <vector>
#include "absl/base/log_severity.h"
#include "absl/log/globals.h"
#include "absl/log/log.h"
#include "absl/strings/match.h"
#include "absl/strings/string_view.h"
#include "ortools/base/init_google.h"
#include "ortools/linear_solver/linear_solver.h"
namespace operations_research {
void RunIntegerProgrammingExample(const std::string& solver_id) {
LOG(INFO) << "---- Integer programming example with " << solver_id << " ----";
std::unique_ptr<MPSolver> solver(MPSolver::CreateSolver(solver_id));
if (!solver) {
LOG(INFO) << "Unable to create solver : " << solver_id;
return;
}
const double infinity = solver->infinity();
// x and y are integer non-negative variables.
MPVariable* const x = solver->MakeIntVar(0.0, infinity, "x");
MPVariable* const y = solver->MakeIntVar(0.0, infinity, "y");
// Maximize x + 10 * y.
MPObjective* const objective = solver->MutableObjective();
objective->SetCoefficient(x, 1);
objective->SetCoefficient(y, 10);
objective->SetMaximization();
// x + 7 * y <= 17.5.
MPConstraint* const c0 = solver->MakeRowConstraint(-infinity, 17.5);
c0->SetCoefficient(x, 1);
c0->SetCoefficient(y, 7);
// x <= 3.5
MPConstraint* const c1 = solver->MakeRowConstraint(-infinity, 3.5);
c1->SetCoefficient(x, 1);
c1->SetCoefficient(y, 0);
LOG(INFO) << "Number of variables = " << solver->NumVariables();
LOG(INFO) << "Number of constraints = " << solver->NumConstraints();
const MPSolver::ResultStatus result_status = solver->Solve();
// Check that the problem has an optimal solution.
if (result_status != MPSolver::OPTIMAL) {
LOG(FATAL) << "The problem does not have an optimal solution!";
}
LOG(INFO) << "Solution:";
LOG(INFO) << "x = " << x->solution_value();
LOG(INFO) << "y = " << y->solution_value();
LOG(INFO) << "Optimal objective value = " << objective->Value();
LOG(INFO) << "";
LOG(INFO) << "Advanced usage:";
LOG(INFO) << "Problem solved in " << solver->wall_time() << " milliseconds";
LOG(INFO) << "Problem solved in " << solver->iterations() << " iterations";
LOG(INFO) << "Problem solved in " << solver->nodes()
<< " branch-and-bound nodes";
}
void RunAllExamples() {
std::vector<MPSolver::OptimizationProblemType> supported_problem_types =
MPSolverInterfaceFactoryRepository::GetInstance()
->ListAllRegisteredProblemTypes();
for (MPSolver::OptimizationProblemType type : supported_problem_types) {
const std::string type_name = MPModelRequest::SolverType_Name(
static_cast<MPModelRequest::SolverType>(type));
if (!SolverTypeIsMip(type)) continue;
if (absl::StrContains(type_name, "KNAPSACK")) continue;
if (absl::StrContains(type_name, "BOP")) continue;
if (absl::StrContains(type_name, "HIGHS")) continue;
// ASAN issues a warning in CBC code which cannot be avoided for now:
// AddressSanitizer: float-cast-overflow
// third_party/cbc/Cgl/src/CglPreProcess/CglPreProcess.cpp:1717:36
#ifdef ADDRESS_SANITIZER
if (type_name.find("CBC") != std::string::npos) {
continue;
}
#endif
RunIntegerProgrammingExample(type_name);
}
}
} // namespace operations_research
int main(int argc, char** argv) {
absl::SetStderrThreshold(absl::LogSeverityAtLeast::kInfo);
InitGoogle(argv[0], &argc, &argv, true);
operations_research::RunAllExamples();
return EXIT_SUCCESS;
}