Function create_operator

cpp/test/matrix.cpp:31–57

/// @return The assembled matrix
template <std::floating_point T>
la::MatrixCSR<T> create_operator(MPI_Comm comm)
{
  auto part = mesh::create_cell_partitioner(mesh::GhostMode::none, 2);
  auto mesh = std::make_shared<mesh::Mesh<T>>(
      mesh::create_box(comm, {{{0.0, 0.0, 0.0}, {1.0, 1.0, 1.0}}}, {12, 12, 12},
                       mesh::CellType::tetrahedron, part));
  auto element = basix::create_element<T>(
      basix::element::family::P, basix::cell::type::tetrahedron, 2,
      basix::element::lagrange_variant::unset,
      basix::element::dpc_variant::unset, false);

  auto V = std::make_shared<fem::FunctionSpace<T>>(fem::create_functionspace<T>(
      mesh, std::make_shared<fem::FiniteElement<T>>(element)));

  // Prepare and set Constants for the bilinear form
  auto kappa = std::make_shared<fem::Constant<T>>(2.0);
  auto a = std::make_shared<fem::Form<T, T>>(fem::create_form<T, T>(
      *form_poisson_a, {V, V}, {}, {{"kappa", kappa}}, {}, {}));

  la::SparsityPattern sp = fem::create_sparsity_pattern(*a);
  sp.finalize();
  la::MatrixCSR<T> A(sp);
  fem::assemble_matrix(A.mat_add_values(), *a, {});
  A.scatter_rev();

  return A;
}

void test_matrix_norm()
{