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backport linear_solver, math_opt, pdlp and util from main

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Corentin Le Molgat
2024-03-25 11:54:18 +01:00
parent 2b0085be7d
commit c9b1ad998a
62 changed files with 1141 additions and 395 deletions
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47
ortools/linear_solver/samples/basic_example.cc
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@@ -11,20 +11,31 @@
// See the License for the specific language governing permissions and
// limitations under the License.
// Minimal example to call the GLOP solver.
// [START program]
// Minimal example to call the GLOP solver.
// [START import]
#include <cstdlib>
#include <memory>
#include <ostream>
#include "absl/flags/flag.h"
#include "absl/log/flags.h"
#include "ortools/base/init_google.h"
#include "ortools/base/logging.h"
#include "ortools/init/init.h"
#include "ortools/linear_solver/linear_solver.h"
// [END import]
namespace operations_research {
void BasicExample() {
LOG(INFO) << "Google OR-Tools version : " << OrToolsVersion::VersionString();
// [START solver]
// Create the linear solver with the GLOP backend.
std::unique_ptr<MPSolver> solver(MPSolver::CreateSolver("GLOP"));
if (!solver) {
LOG(WARNING) << "Could not create solver GLOP";
return;
}
// [END solver]
// [START variables]
@@ -36,8 +47,9 @@ void BasicExample() {
// [END variables]
// [START constraints]
// Create a linear constraint, 0 <= x + y <= 2.
MPConstraint* const ct = solver->MakeRowConstraint(0.0, 2.0, "ct");
// Create a linear constraint, x + y <= 2.
const double infinity = solver->infinity();
MPConstraint* const ct = solver->MakeRowConstraint(-infinity, 2.0, "ct");
ct->SetCoefficient(x, 1);
ct->SetCoefficient(y, 1);
@@ -53,19 +65,40 @@ void BasicExample() {
// [END objective]
// [START solve]
solver->Solve();
LOG(INFO) << "Solving with " << solver->SolverVersion();
const MPSolver::ResultStatus result_status = solver->Solve();
// [END solve]
// [START print_solution]
LOG(INFO) << "Solution:" << std::endl;
// Check that the problem has an optimal solution.
LOG(INFO) << "Status: " << result_status;
if (result_status != MPSolver::OPTIMAL) {
LOG(INFO) << "The problem does not have an optimal solution!";
if (result_status == MPSolver::FEASIBLE) {
LOG(INFO) << "A potentially suboptimal solution was found";
} else {
LOG(WARNING) << "The solver could not solve the problem.";
return;
}
}
LOG(INFO) << "Solution:";
LOG(INFO) << "Objective value = " << objective->Value();
LOG(INFO) << "x = " << x->solution_value();
LOG(INFO) << "y = " << y->solution_value();
// [END print_solution]
// [START advanced]
LOG(INFO) << "Advanced usage:";
LOG(INFO) << "Problem solved in " << solver->wall_time() << " milliseconds";
LOG(INFO) << "Problem solved in " << solver->iterations() << " iterations";
// [END advanced]
}
} // namespace operations_research
int main() {
int main(int argc, char* argv[]) {
InitGoogle(argv[0], &argc, &argv, true);
absl::SetFlag(&FLAGS_stderrthreshold, 0);
operations_research::BasicExample();
return EXIT_SUCCESS;
}