Function assemble_matrix1

cpp/demo/custom_kernel/main.cpp:131–150

/// @return Frobenius norm squared of the matrix.
template <std::floating_point T>
double assemble_matrix1(const mesh::Geometry<T>& g, const fem::DofMap& dofmap,
                        auto kernel, std::span<const std::int32_t> cells)
{
  auto sp = la::SparsityPattern(dofmap.index_map->comm(),
                                {dofmap.index_map, dofmap.index_map},
                                {dofmap.index_map_bs(), dofmap.index_map_bs()});
  fem::sparsitybuild::cells(sp, std::pair{cells, cells}, {dofmap, dofmap});
  sp.finalize();
  la::MatrixCSR<T> A(sp);
  auto ident = [](auto, auto, auto, auto) {}; // DOF permutation not required
  common::Timer timer("Assembler1 lambda (matrix)");
  md::mdspan<const T, md::extents<std::size_t, md::dynamic_extent, 3>> x(
      g.x().data(), g.x().size() / 3, 3);
  fem::impl::assemble_cells_matrix<T>(A.mat_add_values(), g.dofmaps().front(),
                                      x, cells, {dofmap.map(), 1, cells}, ident,
                                      {dofmap.map(), 1, cells}, ident, {}, {},
                                      kernel, {}, {}, {}, {});
  A.scatter_rev();
  return A.squared_norm();
}

/// @brief Assemble a RHS vector using using a lambda kernel function.
///