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Use CreateSolver everywhere and check SCIP (Fix #2395)

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Mizux Seiha
2021-03-31 16:05:32 +02:00
parent 1f7e6399e9
commit 6faa70e7dc
7 changed files with 77 additions and 52 deletions
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27
ortools/linear_solver/samples/linear_programming_example.cc
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@@ -21,46 +21,49 @@
namespace operations_research {
void LinearProgrammingExample() {
// [START solver]
MPSolver solver("linear_programming_examples",
MPSolver::GLOP_LINEAR_PROGRAMMING);
std::unique_ptr<MPSolver> solver(MPSolver::CreateSolver("SCIP"));
if (!solver) {
LOG(WARNING) << "SCIP solver unavailable.";
return;
}
// [END solver]
// [START variables]
const double infinity = solver.infinity();
const double infinity = solver->infinity();
// x and y are non-negative variables.
MPVariable* const x = solver.MakeNumVar(0.0, infinity, "x");
MPVariable* const y = solver.MakeNumVar(0.0, infinity, "y");
LOG(INFO) << "Number of variables = " << solver.NumVariables();
MPVariable* const x = solver->MakeNumVar(0.0, infinity, "x");
MPVariable* const y = solver->MakeNumVar(0.0, infinity, "y");
LOG(INFO) << "Number of variables = " << solver->NumVariables();
// [END variables]
// [START constraints]
// x + 2*y <= 14.
MPConstraint* const c0 = solver.MakeRowConstraint(-infinity, 14.0);
MPConstraint* const c0 = solver->MakeRowConstraint(-infinity, 14.0);
c0->SetCoefficient(x, 1);
c0->SetCoefficient(y, 2);
// 3*x - y >= 0.
MPConstraint* const c1 = solver.MakeRowConstraint(0.0, infinity);
MPConstraint* const c1 = solver->MakeRowConstraint(0.0, infinity);
c1->SetCoefficient(x, 3);
c1->SetCoefficient(y, -1);
// x - y <= 2.
MPConstraint* const c2 = solver.MakeRowConstraint(-infinity, 2.0);
MPConstraint* const c2 = solver->MakeRowConstraint(-infinity, 2.0);
c2->SetCoefficient(x, 1);
c2->SetCoefficient(y, -1);
LOG(INFO) << "Number of constraints = " << solver.NumConstraints();
LOG(INFO) << "Number of constraints = " << solver->NumConstraints();
// [END constraints]
// [START objective]
// Objective function: 3x + 4y.
MPObjective* const objective = solver.MutableObjective();
MPObjective* const objective = solver->MutableObjective();
objective->SetCoefficient(x, 3);
objective->SetCoefficient(y, 4);
objective->SetMaximization();
// [END objective]
// [START solve]
const MPSolver::ResultStatus result_status = solver.Solve();
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!";