Files
mfem/examples/dfem_refactor.cpp
T

103 lines
3.0 KiB
C++

#include "mfem.hpp"
#include "dfem/dfem_refactor.hpp"
using namespace mfem;
auto main(int argc, char *argv[]) -> int
{
Mpi::Init();
std::cout << std::setprecision(9);
const char *mesh_file = "../data/star.mesh";
int polynomial_order = 1;
int refinements = 0;
OptionsParser args(argc, argv);
args.AddOption(&mesh_file, "-m", "--mesh", "Mesh file to use.");
args.AddOption(&polynomial_order, "-o", "--order", "");
args.AddOption(&refinements, "-r", "--r", "");
args.ParseCheck();
Mesh mesh_serial(mesh_file, 1, 1);
mesh_serial.SetCurvature(1);
for (int i = 0; i < refinements; i++)
{
mesh_serial.UniformRefinement();
}
const int dim = mesh_serial.Dimension();
ParMesh mesh(MPI_COMM_WORLD, mesh_serial);
mesh_serial.Clear();
ParGridFunction* mesh_nodes = static_cast<ParGridFunction *>(mesh.GetNodes());
ParFiniteElementSpace &mesh_fes = *mesh_nodes->ParFESpace();
constexpr int vdim = 1;
H1_FECollection h1fec(polynomial_order, dim);
ParFiniteElementSpace h1fes(&mesh, &h1fec, vdim);
Array<int> ess_tdof_list;
Array<int> ess_bdr(mesh.bdr_attributes.Max());
ess_bdr = 1;
h1fes.GetEssentialTrueDofs(ess_bdr, ess_tdof_list);
const IntegrationRule &ir =
IntRules.Get(h1fes.GetFE(0)->GetGeomType(), 2 * h1fec.GetOrder() + 1);
std::cout << "nqpts = " << ir.GetNPoints() << std::endl;
std::cout << "ndofs = " << h1fes.GlobalTrueVSize() << std::endl;
ParGridFunction u(&h1fes);
auto exact_solution = [](const Vector &coords)
{
const double x = coords(0);
const double y = coords(1);
return 2.345 + x + y;
};
FunctionCoefficient exact_solution_coeff(exact_solution);
u.ProjectCoefficient(exact_solution_coeff);
auto domain_qf = [](const double &u,
const tensor<double, 2, 2> &J,
const double &w)
{
out << u << "\n" << J << "\n" << w << "\n\n";
return std::tuple{u * det(J) * w};
};
std::tuple input_descriptors = {Value{"potential"}, Gradient{"coordinates"}, Weight{"integration_weights"}};
std::tuple output_descriptors = {Value{"potential"}};
ElementOperator eop{domain_qf, input_descriptors, output_descriptors};
auto ops = std::tuple{eop};
auto solutions = std::array{FieldDescriptor{&h1fes, "potential"}};
auto parameters = std::array{FieldDescriptor{&mesh_fes, "coordinates"}};
DifferentiableOperator dop{solutions, parameters, ops, mesh, ir};
Vector x(h1fes.GetTrueVSize()), y(h1fes.GetTrueVSize());
u.GetTrueDofs(x);
dop.SetParameters({mesh_nodes});
dop.Mult(x, y);
// Derivative wrt "potential", indicated by the index 0 of the set {solutions} \cup {parameters}
auto dFd0 = dop.GetDerivativeWrt<0>({&u}, {mesh_nodes});
dFd0->Mult(x, y);
Vector dFd0_vec;
dFd0->Assemble(dFd0_vec);
// Derivative wrt "coordinates", indicated by the index 1 of the set {solutions} \cup {parameters}
auto dFd1 = dop.GetDerivativeWrt<1>({&u}, {mesh_nodes});
dFd1->Mult(x, y);
return 0;
}