--- /dev/null
+// ---------------------------------------------------------------------
+// $Id$
+//
+// Copyright (C) 2014 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 at
+// the top level of the deal.II distribution.
+//
+// ---------------------------------------------------------------------
+
+
+
+// A variant of step-6 that replaces loops over cells with range-based for
+// loops a la C++11
+
+#include "../tests.h"
+#include <deal.II/base/quadrature_lib.h>
+#include <deal.II/base/function.h>
+#include <deal.II/base/logstream.h>
+#include <deal.II/lac/vector.h>
+#include <deal.II/lac/full_matrix.h>
+#include <deal.II/lac/sparse_matrix.h>
+#include <deal.II/lac/compressed_sparsity_pattern.h>
+#include <deal.II/lac/solver_cg.h>
+#include <deal.II/lac/precondition.h>
+#include <deal.II/grid/tria.h>
+#include <deal.II/dofs/dof_handler.h>
+#include <deal.II/grid/grid_generator.h>
+#include <deal.II/grid/tria_accessor.h>
+#include <deal.II/grid/tria_iterator.h>
+#include <deal.II/grid/tria_boundary_lib.h>
+#include <deal.II/dofs/dof_accessor.h>
+#include <deal.II/dofs/dof_tools.h>
+#include <deal.II/fe/fe_values.h>
+#include <deal.II/numerics/vector_tools.h>
+#include <deal.II/numerics/matrix_tools.h>
+#include <deal.II/numerics/data_out.h>
+
+#include <fstream>
+#include <iostream>
+
+#include <deal.II/fe/fe_q.h>
+#include <deal.II/grid/grid_out.h>
+
+
+#include <deal.II/lac/constraint_matrix.h>
+
+#include <deal.II/grid/grid_refinement.h>
+
+#include <deal.II/numerics/error_estimator.h>
+
+using namespace dealii;
+
+
+
+template <int dim>
+class Step6
+{
+public:
+ Step6 ();
+ ~Step6 ();
+
+ void run ();
+
+private:
+ void setup_system ();
+ void assemble_system ();
+ void solve ();
+ void refine_grid ();
+ void output_results (const unsigned int cycle) const;
+
+ Triangulation<dim> triangulation;
+
+ DoFHandler<dim> dof_handler;
+ FE_Q<dim> fe;
+
+ ConstraintMatrix constraints;
+
+ SparsityPattern sparsity_pattern;
+ SparseMatrix<double> system_matrix;
+
+ Vector<double> solution;
+ Vector<double> system_rhs;
+};
+
+
+
+
+template <int dim>
+class Coefficient : public Function<dim>
+{
+public:
+ Coefficient () : Function<dim>() {}
+
+ virtual double value (const Point<dim> &p,
+ const unsigned int component = 0) const;
+
+ virtual void value_list (const std::vector<Point<dim> > &points,
+ std::vector<double> &values,
+ const unsigned int component = 0) const;
+};
+
+
+
+template <int dim>
+double Coefficient<dim>::value (const Point<dim> &p,
+ const unsigned int) const
+{
+ if (p.square() < 0.5*0.5)
+ return 20;
+ else
+ return 1;
+}
+
+
+
+template <int dim>
+void Coefficient<dim>::value_list (const std::vector<Point<dim> > &points,
+ std::vector<double> &values,
+ const unsigned int component) const
+{
+ const unsigned int n_points = points.size();
+
+ Assert (values.size() == n_points,
+ ExcDimensionMismatch (values.size(), n_points));
+
+ Assert (component == 0,
+ ExcIndexRange (component, 0, 1));
+
+ for (unsigned int i=0; i<n_points; ++i)
+ {
+ if (points[i].square() < 0.5*0.5)
+ values[i] = 20;
+ else
+ values[i] = 1;
+ }
+}
+
+
+
+
+template <int dim>
+Step6<dim>::Step6 ()
+ :
+ dof_handler (triangulation),
+ fe (2)
+{}
+
+
+
+template <int dim>
+Step6<dim>::~Step6 ()
+{
+ dof_handler.clear ();
+}
+
+
+
+template <int dim>
+void Step6<dim>::setup_system ()
+{
+ dof_handler.distribute_dofs (fe);
+
+ solution.reinit (dof_handler.n_dofs());
+ system_rhs.reinit (dof_handler.n_dofs());
+
+
+ constraints.clear ();
+ DoFTools::make_hanging_node_constraints (dof_handler,
+ constraints);
+
+
+ VectorTools::interpolate_boundary_values (dof_handler,
+ 0,
+ ZeroFunction<dim>(),
+ constraints);
+
+
+ constraints.close ();
+
+ CompressedSparsityPattern c_sparsity(dof_handler.n_dofs());
+ DoFTools::make_sparsity_pattern(dof_handler,
+ c_sparsity,
+ constraints,
+ /*keep_constrained_dofs = */ false);
+
+ sparsity_pattern.copy_from(c_sparsity);
+
+ system_matrix.reinit (sparsity_pattern);
+}
+
+
+
+template <int dim>
+void Step6<dim>::assemble_system ()
+{
+ const QGauss<dim> quadrature_formula(3);
+
+ FEValues<dim> fe_values (fe, quadrature_formula,
+ update_values | update_gradients |
+ update_quadrature_points | update_JxW_values);
+
+ const unsigned int dofs_per_cell = fe.dofs_per_cell;
+ const unsigned int n_q_points = quadrature_formula.size();
+
+ FullMatrix<double> cell_matrix (dofs_per_cell, dofs_per_cell);
+ Vector<double> cell_rhs (dofs_per_cell);
+
+ std::vector<types::global_dof_index> local_dof_indices (dofs_per_cell);
+
+ const Coefficient<dim> coefficient;
+ std::vector<double> coefficient_values (n_q_points);
+
+ for (auto cell : dof_handler.active_cell_iterators())
+ {
+ cell_matrix = 0;
+ cell_rhs = 0;
+
+ fe_values.reinit (cell);
+
+ coefficient.value_list (fe_values.get_quadrature_points(),
+ coefficient_values);
+
+ for (unsigned int q_index=0; q_index<n_q_points; ++q_index)
+ for (unsigned int i=0; i<dofs_per_cell; ++i)
+ {
+ for (unsigned int j=0; j<dofs_per_cell; ++j)
+ cell_matrix(i,j) += (coefficient_values[q_index] *
+ fe_values.shape_grad(i,q_index) *
+ fe_values.shape_grad(j,q_index) *
+ fe_values.JxW(q_index));
+
+ cell_rhs(i) += (fe_values.shape_value(i,q_index) *
+ 1.0 *
+ fe_values.JxW(q_index));
+ }
+
+ cell->get_dof_indices (local_dof_indices);
+ constraints.distribute_local_to_global (cell_matrix,
+ cell_rhs,
+ local_dof_indices,
+ system_matrix,
+ system_rhs);
+ }
+}
+
+
+
+
+template <int dim>
+void Step6<dim>::solve ()
+{
+ SolverControl solver_control (1000, 1e-12);
+ SolverCG<> solver (solver_control);
+
+ PreconditionSSOR<> preconditioner;
+ preconditioner.initialize(system_matrix, 1.2);
+
+ solver.solve (system_matrix, solution, system_rhs,
+ preconditioner);
+
+ constraints.distribute (solution);
+}
+
+
+
+template <int dim>
+void Step6<dim>::refine_grid ()
+{
+ Vector<float> estimated_error_per_cell (triangulation.n_active_cells());
+
+ KellyErrorEstimator<dim>::estimate (dof_handler,
+ QGauss<dim-1>(3),
+ typename FunctionMap<dim>::type(),
+ solution,
+ estimated_error_per_cell);
+
+ GridRefinement::refine_and_coarsen_fixed_number (triangulation,
+ estimated_error_per_cell,
+ 0.3, 0.03);
+
+ triangulation.execute_coarsening_and_refinement ();
+}
+
+
+
+template <int dim>
+void Step6<dim>::output_results (const unsigned int cycle) const
+{
+ Assert (cycle < 10, ExcNotImplemented());
+
+ std::string filename = "grid-";
+ filename += ('0' + cycle);
+ filename += ".eps";
+
+ std::ofstream output (filename.c_str());
+
+ GridOut grid_out;
+ grid_out.write_eps (triangulation, output);
+}
+
+
+
+template <int dim>
+void Step6<dim>::run ()
+{
+ for (unsigned int cycle=0; cycle<3; ++cycle)
+ {
+ deallog << "Cycle " << cycle << ':' << std::endl;
+
+ if (cycle == 0)
+ {
+ GridGenerator::hyper_ball (triangulation);
+
+ static const HyperBallBoundary<dim> boundary;
+ triangulation.set_boundary (0, boundary);
+
+ triangulation.refine_global (1);
+ }
+ else
+ refine_grid ();
+
+
+ deallog << " Number of active cells: "
+ << triangulation.n_active_cells()
+ << std::endl;
+
+ setup_system ();
+
+ deallog << " Number of degrees of freedom: "
+ << dof_handler.n_dofs()
+ << std::endl;
+
+ assemble_system ();
+ solve ();
+ }
+}
+
+
+
+int main ()
+{
+ std::ofstream logfile ("output");
+ deallog << std::setprecision (3);
+
+ deallog.attach(logfile);
+ deallog.depth_console (0);
+ deallog.threshold_double(1.e-7);
+
+ Step6<2> laplace_problem_2d;
+ laplace_problem_2d.run ();
+}
projects / dealii.git / commitdiff