--- /dev/null
+// ---------------------------------------------------------------------
+//
+// Copyright (C) 2003 - 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.
+//
+// ---------------------------------------------------------------------
+
+
+// Test integrate_difference
+
+#include "../tests.h"
+#include <deal.II/base/function.h>
+#include <deal.II/base/quadrature_lib.h>
+#include <deal.II/numerics/vector_tools.h>
+#include <deal.II/lac/vector.h>
+#include <deal.II/dofs/dof_tools.h>
+#include <deal.II/grid/tria.h>
+#include <deal.II/grid/tria_accessor.h>
+#include <deal.II/grid/grid_generator.h>
+#include <deal.II/grid/grid_refinement.h>
+#include <deal.II/fe/fe_q.h>
+#include <deal.II/fe/fe_system.h>
+
+using namespace dealii;
+
+
+// x+y(+z), x^2+y^2 (, z+xy)
+// div = 1+2y (+1)
+template <int dim>
+class Ref : public Function<dim>
+{
+ public:
+ Ref()
+ :Function<dim>(dim)
+ {}
+
+ double value (const Point<dim> &p, const unsigned int c) const
+ {
+ if (c==0)
+ return p[0]+p[1]+((dim==3)?p[2]:0.0);
+ if (c==1)
+ return p[0]*p[0]+p[1]*p[1];
+ if (c==2)
+ return p[2]+p[0]*p[1];
+ }
+};
+
+
+
+template <int dim>
+void test(VectorTools::NormType norm, double value)
+{
+ Triangulation<dim> tria;
+ GridGenerator::hyper_cube(tria);
+ tria.refine_global(1);
+
+ FESystem<dim> fe(FE_Q<dim>(4),dim);
+ DoFHandler<dim> dofh(tria);
+ dofh.distribute_dofs(fe);
+
+ Vector<double> solution (dofh.n_dofs ());
+ VectorTools::interpolate(dofh, Ref<dim>(), solution);
+
+ Vector<double> cellwise_errors (tria.n_active_cells());
+ VectorTools::integrate_difference (dofh,
+ solution,
+ ZeroFunction<dim>(dim),
+ cellwise_errors,
+ QGauss<dim>(5),
+ norm);
+
+ const double error = cellwise_errors.l2_norm();
+
+ const double difference = std::abs(error-value);
+ deallog << "computed: " << error
+ << " expected: " << value
+ << " difference: " << difference
+ << std::endl;
+ Assert(difference<1e-10, ExcMessage("Error in integrate_difference"));
+}
+
+template <int dim>
+void test()
+{
+ deallog << "Hdiv_seminorm:" << std::endl;
+ // sqrt(\int (div f)^2 = sqrt(\int (1+2y)^2)
+ test<dim>(VectorTools::Hdiv_seminorm, std::sqrt(13.0/3.0));
+ deallog << "L2_norm:" << std::endl;
+ // sqrt(\int_\Omega f^2) = sqrt(\int (x+y)^2+(x^2+y^2)^2)
+ test<dim>(VectorTools::L2_norm, std::sqrt(161.0/90.0));
+
+ deallog << "OK" << std::endl;
+}
+
+
+int main (int argc, char **argv)
+{
+ initlog();
+ test<2>();
+
+}