From: bangerth <bangerth@0785d39b-7218-0410-832d-ea1e28bc413d>
Date: Mon, 3 Feb 2014 19:41:25 +0000 (+0000)
Subject: One more test for curls.
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=154b77941733e6f17ad2163b28be7572522998cc;p=dealii-svn.git

One more test for curls.

git-svn-id: https://svn.dealii.org/trunk@32395 0785d39b-7218-0410-832d-ea1e28bc413d
---

diff --git a/tests/deal.II/fe_values_view_29.cc b/tests/deal.II/fe_values_view_29.cc
new file mode 100644
index 0000000000..eff1147724
--- /dev/null
+++ b/tests/deal.II/fe_values_view_29.cc
@@ -0,0 +1,153 @@
+// ---------------------------------------------------------------------
+// $Id$
+//
+// Copyright (C) 2007 - 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.
+//
+// ---------------------------------------------------------------------
+
+
+
+// like _28 but also test a non-primitive element.
+
+#include "../tests.h"
+#include <deal.II/base/logstream.h>
+#include <deal.II/base/function.h>
+#include <deal.II/base/quadrature_lib.h>
+#include <deal.II/lac/vector.h>
+#include <deal.II/grid/grid_generator.h>
+#include <deal.II/grid/tria_boundary_lib.h>
+#include <deal.II/dofs/dof_handler.h>
+#include <deal.II/fe/fe_nedelec.h>
+#include <deal.II/fe/fe_system.h>
+#include <deal.II/fe/fe_values.h>
+#include <deal.II/numerics/vector_tools.h>
+#include <deal.II/numerics/data_out.h>
+
+#include <fstream>
+
+
+class F : public Function<2>
+{
+public:
+  F() : Function<2>(2) {}
+
+  virtual void vector_value (const Point<2> &p,
+			     Vector<double> &v) const
+    {
+      // make the function equal to (0,x^2)
+      v[0] = 0;
+      v[1] = p[0]*p[0];
+    }
+};
+
+
+
+Tensor<1,1> curl (const Tensor<2,2> &grads)
+{
+  return Point<1>(grads[1][0] - grads[0][1]);
+}
+
+
+Tensor<1,3> curl (const Tensor<2,3> &grads)
+{
+  return Point<3>(grads[2][1] - grads[1][2],
+		  grads[0][2] - grads[2][0],
+		  grads[1][0] - grads[0][1]);
+}
+
+
+
+template<int dim>
+void test (const Triangulation<dim> &tr,
+           const FiniteElement<dim> &fe)
+{
+  deallog << "FE=" << fe.get_name()
+          << std::endl;
+
+  DoFHandler<dim> dof(tr);
+  dof.distribute_dofs(fe);
+
+  Vector<double> fe_function(dof.n_dofs());
+  // set the elements of the vector in such a way that the function
+  // equals the vector function (0,x^2)
+  ConstraintMatrix cm;
+  cm.close ();
+  VectorTools::project (dof, cm, QGauss<2>(4), F(), fe_function);
+
+  // verify that we really have something that after projection equals the
+  // original
+  {
+    DataOut<dim> x;
+    x.attach_dof_handler (dof);
+    x.add_data_vector (fe_function, "u");
+    std::ofstream o("x.gnuplot");
+    x.build_patches(6);
+    x.write_gnuplot (o);
+  }
+  
+  const QGauss<dim> quadrature(2);
+  FEValues<dim> fe_values (fe, quadrature,
+                           update_values | update_gradients | update_q_points);
+  fe_values.reinit (dof.begin_active());
+
+  // let the FEValues object compute the
+  // divergences at quadrature points
+  std::vector<typename dealii::internal::CurlType<dim>::type> curls (quadrature.size());
+  std::vector<Tensor<2,dim> > grads (quadrature.size());
+  FEValuesExtractors::Vector extractor(0);
+  fe_values[extractor].get_function_curls (fe_function, curls);
+  fe_values[extractor].get_function_gradients (fe_function, grads);
+
+  // now compare
+  for (unsigned int q=0; q<quadrature.size(); ++q)
+    {
+      deallog << "  curls[q]= " << curls[q] << std::endl
+	      << "  grads[q]= " << grads[q] << std::endl;
+      Assert ((curl(grads[q]) - curls[q]).norm()
+	      <= 1e-10,
+	      ExcInternalError());
+
+      // we know the function F=(0,x^2) and we chose an element with
+      // high enough degree to exactly represent this function, so the
+      // curl of this function should be
+      //   curl F = d_x F_y - d_y F_x = 2x
+      // verify that this is true
+      Assert (std::fabs(curls[q][0] - 2*fe_values.quadrature_point(q)[0])
+	      <= 1e-10,
+	      ExcInternalError());
+    }
+}
+
+
+
+template<int dim>
+void test_hyper_cube()
+{
+  Triangulation<dim> tr;
+  GridGenerator::hyper_cube(tr);
+
+  FE_Nedelec<dim> fe(2);
+  test(tr, fe);
+}
+
+
+int main()
+{
+  std::ofstream logfile ("output");
+  deallog << std::setprecision (3);
+
+  deallog.attach(logfile);
+  deallog.depth_console (0);
+  deallog.threshold_double(1.e-7);
+
+  test_hyper_cube<2>();
+}
diff --git a/tests/deal.II/fe_values_view_29.output b/tests/deal.II/fe_values_view_29.output
new file mode 100644
index 0000000000..534b134add
--- /dev/null
+++ b/tests/deal.II/fe_values_view_29.output
@@ -0,0 +1,10 @@
+
+DEAL::FE=FE_Nedelec<2>(2)
+DEAL::  curls[q]= 0.423
+DEAL::  grads[q]= 0.00 0.00 0.423 -1.98e-16
+DEAL::  curls[q]= 1.58
+DEAL::  grads[q]= 0.00 0.00 1.58 4.45e-16
+DEAL::  curls[q]= 0.423
+DEAL::  grads[q]= 0.00 0.00 0.423 -2.00e-16
+DEAL::  curls[q]= 1.58
+DEAL::  grads[q]= 0.00 0.00 1.58 -3.38e-16