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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/integer_programming_example.cc
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@@ -22,45 +22,48 @@ namespace operations_research {
void IntegerProgrammingExample() {
// [START solver]
// Create the mip solver with the SCIP backend.
MPSolver solver("integer_programming_example",
MPSolver::SCIP_MIXED_INTEGER_PROGRAMMING);
std::unique_ptr<MPSolver> solver(MPSolver::CreateSolver("SCIP"));
if (!solver) {
LOG(WARNING) << "SCIP solver unavailable.";
return;
}
// [END solver]
// [START variables]
// x, y, and z are non-negative integer variables.
MPVariable* const x = solver.MakeIntVar(0.0, solver.infinity(), "x");
MPVariable* const y = solver.MakeIntVar(0.0, solver.infinity(), "y");
MPVariable* const z = solver.MakeIntVar(0.0, solver.infinity(), "z");
LOG(INFO) << "Number of variables = " << solver.NumVariables();
MPVariable* const x = solver->MakeIntVar(0.0, solver->infinity(), "x");
MPVariable* const y = solver->MakeIntVar(0.0, solver->infinity(), "y");
MPVariable* const z = solver->MakeIntVar(0.0, solver->infinity(), "z");
LOG(INFO) << "Number of variables = " << solver->NumVariables();
// [END variables]
// [START constraints]
// 2*x + 7*y + 3*z <= 50
MPConstraint* const constraint0 =
solver.MakeRowConstraint(-solver.infinity(), 50);
solver->MakeRowConstraint(-solver->infinity(), 50);
constraint0->SetCoefficient(x, 2);
constraint0->SetCoefficient(y, 7);
constraint0->SetCoefficient(z, 3);
// 3*x - 5*y + 7*z <= 45
MPConstraint* const constraint1 =
solver.MakeRowConstraint(-solver.infinity(), 45);
solver->MakeRowConstraint(-solver->infinity(), 45);
constraint1->SetCoefficient(x, 3);
constraint1->SetCoefficient(y, -5);
constraint1->SetCoefficient(z, 7);
// 5*x + 2*y - 6*z <= 37
MPConstraint* const constraint2 =
solver.MakeRowConstraint(-solver.infinity(), 37);
solver->MakeRowConstraint(-solver->infinity(), 37);
constraint2->SetCoefficient(x, 5);
constraint2->SetCoefficient(y, 2);
constraint2->SetCoefficient(z, -6);
LOG(INFO) << "Number of constraints = " << solver.NumConstraints();
LOG(INFO) << "Number of constraints = " << solver->NumConstraints();
// [END constraints]
// [START objective]
// Maximize 2*x + 2*y + 3*z
MPObjective* const objective = solver.MutableObjective();
MPObjective* const objective = solver->MutableObjective();
objective->SetCoefficient(x, 2);
objective->SetCoefficient(y, 2);
objective->SetCoefficient(z, 3);
@@ -68,7 +71,7 @@ void IntegerProgrammingExample() {
// [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!";