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mfem/examples/dfem_test_vector_diffusion.cpp
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2024-10-15 12:44:20 -07:00

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2.9 KiB
C++

#include "dfem/dfem.hpp"
#include "dfem/dfem_test_macro.hpp"
using namespace mfem;
using mfem::internal::tensor;
int test_vector_diffusion(std::string mesh_file,
int refinements,
int polynomial_order)
{
Mesh mesh_serial = Mesh(mesh_file);
for (int i = 0; i < refinements; i++)
{
mesh_serial.UniformRefinement();
}
ParMesh mesh(MPI_COMM_WORLD, mesh_serial);
mesh.SetCurvature(1);
const int dim = mesh.Dimension();
const int vdim = dim;
mesh_serial.Clear();
ParGridFunction* mesh_nodes = static_cast<ParGridFunction *>(mesh.GetNodes());
ParFiniteElementSpace &mesh_fes = *mesh_nodes->ParFESpace();
H1_FECollection h1fec(polynomial_order, dim);
ParFiniteElementSpace h1fes(&mesh, &h1fec, vdim);
Array<int> ess_bdr(mesh.bdr_attributes.Max());
Array<int> ess_tdof;
ess_bdr = 1;
h1fes.GetEssentialTrueDofs(ess_bdr, ess_tdof);
const IntegrationRule &ir =
IntRules.Get(h1fes.GetFE(0)->GetGeomType(), 2 * h1fec.GetOrder() - 1);
ParGridFunction u(&h1fes);
auto f1 = [](const Vector& coords, Vector &u)
{
const double x = coords(0);
const double y = coords(1);
u(0) = 2.345 + 0.25 * x * x * y + y * y * x;
u(1) = 2.345 - 0.25 * x * y * y + y * x * x;
};
VectorFunctionCoefficient u_c(dim, f1);
u.ProjectCoefficient(u_c);
auto vector_diffusion_kernel = [](const tensor<double, 2> &xi,
const tensor<double, 2, 2> &dudxi,
const tensor<double, 2, 2> &J,
const double &w)
{
out << "xi: " << xi << "\n";
out << "dudxi: " << dudxi << "\n";
return mfem::tuple{dudxi * inv(J) * det(J) * w * transpose(inv(J))};
// return mfem::tuple{dudxi};
};
mfem::tuple argument_operators{Value{"coordinates"}, Gradient{"potential"}, Gradient{"coordinates"}, Weight{}};
mfem::tuple output_operator{Gradient{"potential"}};
ElementOperator op{vector_diffusion_kernel, argument_operators, output_operator};
std::array solutions{FieldDescriptor{&h1fes, "potential"}};
std::array parameters{FieldDescriptor{&mesh_fes, "coordinates"}};
DifferentiableOperator dop{solutions, parameters, mfem::tuple{op}, mesh, ir};
Vector x(u), y1(h1fes.GetTrueVSize()),
y2(h1fes.GetTrueVSize());
ParBilinearForm A_form(&h1fes);
auto A_integ = new VectorDiffusionIntegrator(vdim);
A_integ->SetIntegrationRule(ir);
A_form.AddDomainIntegrator(A_integ);
A_form.Assemble();
A_form.Finalize();
dop.SetParameters({mesh_nodes});
dop.Mult(x, y1);
y1.HostRead();
A_form.Mult(x, y2);
y2.HostRead();
Vector diff(y2);
diff -= y1;
if (diff.Norml2() > 1e-10)
{
out << "||F(u) - ex||_l2 = " << diff.Norml2() << "\n";
print_vector(diff);
print_vector(y1);
print_vector(y2);
return 1;
}
return 0;
}
DFEM_TEST_MAIN(test_vector_diffusion);