--- /dev/null
+/* ---------------------------------------------------------------------
+ *
+ * Copyright (C) 2018 by the deal.II authors
+ *
+ * This file is part of the deal.II library.
+ *
+ * The deal.II library is free software; you can use it, redistribute
+ * it, and/or modify it under the terms of the GNU Lesser General
+ * Public License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ * The full text of the license can be found in the file LICENSE.md at
+ * the top level directory of deal.II.
+ *
+ * ---------------------------------------------------------------------
+ */
+
+// Compute Laplacian using mesh_loop, sacado, and ScratchData
+
+#include <deal.II/base/function_parser.h>
+#include <deal.II/base/patterns.h>
+#include <deal.II/base/thread_management.h>
+
+#include <deal.II/dofs/dof_tools.h>
+
+#include <deal.II/fe/fe_dgq.h>
+#include <deal.II/fe/fe_q.h>
+
+#include <deal.II/grid/grid_generator.h>
+#include <deal.II/grid/grid_out.h>
+#include <deal.II/grid/grid_tools.h>
+#include <deal.II/grid/grid_tools_cache.h>
+#include <deal.II/grid/tria.h>
+#include <deal.II/grid/tria_accessor.h>
+#include <deal.II/grid/tria_iterator.h>
+
+#include <deal.II/lac/affine_constraints.h>
+#include <deal.II/lac/sparse_direct.h>
+
+#include <deal.II/meshworker/copy_data.h>
+#include <deal.II/meshworker/mesh_loop.h>
+#include <deal.II/meshworker/scratch_data.h>
+
+#include <deal.II/numerics/data_out.h>
+#include <deal.II/numerics/vector_tools.h>
+
+#include <Sacado.hpp>
+
+#include <cmath>
+#include <fstream>
+#include <iostream>
+#include <unordered_map>
+
+#include "../tests.h"
+
+using namespace MeshWorker;
+
+typedef Sacado::Fad::DFad<double> Sdouble;
+typedef Sacado::Fad::DFad<Sdouble> SSdouble;
+
+template <int dim, int spacedim>
+void
+test()
+{
+ Triangulation<dim, spacedim> tria;
+ FE_Q<dim, spacedim> fe(1);
+ DoFHandler<dim, spacedim> dh(tria);
+
+ FunctionParser<spacedim> rhs_function("1");
+ FunctionParser<spacedim> boundary_function("0");
+
+ AffineConstraints<double> constraints;
+
+ GridGenerator::hyper_cube(tria);
+ tria.refine_global(5);
+ tria.execute_coarsening_and_refinement();
+ dh.distribute_dofs(fe);
+
+
+ DoFTools::make_hanging_node_constraints(dh, constraints);
+ VectorTools::interpolate_boundary_values(dh,
+ 0,
+ boundary_function,
+ constraints);
+
+ constraints.close();
+
+ SparsityPattern sparsity;
+
+ {
+ DynamicSparsityPattern dsp(dh.n_dofs(), dh.n_dofs());
+ DoFTools::make_flux_sparsity_pattern(dh, dsp);
+ sparsity.copy_from(dsp);
+ }
+
+ SparseMatrix<double> matrix;
+ matrix.reinit(sparsity);
+
+ Vector<double> solution(dh.n_dofs());
+ Vector<double> rhs(dh.n_dofs());
+
+ QGauss<dim> quad(3);
+
+ UpdateFlags cell_flags = update_values | update_gradients |
+ update_quadrature_points | update_JxW_values;
+
+ using ScratchData = MeshWorker::ScratchData<dim, spacedim>;
+ using CopyData = MeshWorker::CopyData<1, 1, 1>;
+
+ ScratchData scratch(fe, quad, cell_flags);
+ CopyData copy(fe.dofs_per_cell);
+
+ auto cell = dh.begin_active();
+ auto endc = dh.end();
+
+ typedef decltype(cell) Iterator;
+
+ FEValuesExtractors::Scalar scalar(0);
+
+ auto cell_worker = [&rhs_function, &solution, &scalar](const Iterator &cell,
+ ScratchData & s,
+ CopyData & c) {
+ const auto &fev = s.reinit(cell);
+ const auto &JxW = s.get_JxW_values();
+ const auto &p = s.get_quadrature_points();
+
+ Sdouble dummy;
+ std::vector<Sdouble> residual(fev.dofs_per_cell, Sdouble(0));
+
+ s.extract_local_dof_values("solution", solution, dummy);
+ const auto &u = s.get_values("solution", scalar, dummy);
+ const auto &grad_u = s.get_gradients("solution", scalar, dummy);
+
+ c = 0;
+
+ c.local_dof_indices[0] = s.get_local_dof_indices();
+
+ for (unsigned int i = 0; i < fev.dofs_per_cell; ++i)
+ for (unsigned int q = 0; q < p.size(); ++q)
+ {
+ residual[i] += (fev.shape_grad(i, q) * grad_u[q] -
+ rhs_function.value(p[q]) * fev.shape_value(i, q)) *
+ JxW[q];
+ }
+
+ // Copy from Sacado to normal vectors
+ for (unsigned int i = 0; i < fev.dofs_per_cell; ++i)
+ {
+ c.vectors[0][i] = -residual[i].val();
+ for (unsigned int j = 0; j < fev.dofs_per_cell; ++j)
+ c.matrices[0](i, j) = residual[i].dx(j);
+ }
+ };
+
+ auto copier = [&constraints, &matrix, &rhs](const CopyData &c) {
+ constraints.distribute_local_to_global(
+ c.matrices[0], c.vectors[0], c.local_dof_indices[0], matrix, rhs);
+ };
+
+ mesh_loop(cell, endc, cell_worker, copier, scratch, copy, assemble_own_cells);
+
+ SparseDirectUMFPACK inv;
+ inv.initialize(matrix);
+
+ inv.vmult(solution, rhs);
+ constraints.distribute(solution);
+
+ deallog << "Linfty norm of solution: " << solution.linfty_norm() << std::endl;
+}
+
+
+int
+main()
+{
+ initlog(1);
+ MultithreadInfo::set_thread_limit(1); // to make output deterministic
+
+ test<2, 2>();
+}