subdomains_ex3.C File Reference

Go to the source code of this file.

Functions
void	integrate_function (const MeshBase &mesh)
Real	distance (const Point &p)
Real	integrand (const Point &p)
int	main (int argc, char **argv)

Variables
const Real	radius = 0.5

Function Documentation

distance()

Real distance

(

const Point &

p

)

Definition at line 51 of file subdomains_ex3.C.

References libMesh::TensorTools::norm(), and radius.

Referenced by NonManifoldTestPartitioner::_do_partition(), OverlappingTestPartitioner::_do_partition(), libMesh::MeshCommunication::assign_global_indices(), libMesh::InfElemBuilder::build_inf_elem(), libMesh::EquationSystems::build_parallel_solution_vector(), libMesh::Tet::choose_diagonal(), libMesh::MeshCommunication::find_global_indices(), libMesh::RBParametrized::get_closest_value(), libMesh::EquationSystems::get_vars_active_subdomains(), libMesh::ParmetisPartitioner::initialize(), libMesh::ExodusII_IO_Helper::initialize(), LinearElasticityWithContact::initialize_contact_load_paths(), libMesh::ExodusII_IO_Helper::initialize_element_variables(), integrand(), integrate_function(), libMesh::StoredRange< iterator_type, object_type >::is_divisible(), libMesh::Parallel::Histogram< KeyType, IdxType >::local_bin_size(), libMesh::DofMap::local_variable_indices(), libMesh::DistributedVector< T >::localize(), AugmentSparsityOnInterface::mesh_reinit(), libMesh::TriangulatorInterface::MeshedHole::MeshedHole(), libMesh::ReplicatedMesh::n_active_elem(), libMesh::DistributedMesh::n_active_elem(), libMesh::MeshTools::n_active_elem_of_type(), libMesh::MeshBase::n_active_elem_on_proc(), libMesh::BoundaryInfo::n_boundary_ids(), libMesh::MeshTools::n_elem(), libMesh::MeshTools::n_elem_of_type(), libMesh::MeshBase::n_elem_on_proc(), libMesh::DofMap::n_local_constrained_dofs(), libMesh::MeshTools::n_nodes(), libMesh::MeshBase::n_nodes_on_proc(), libMesh::PetscMatrix< T >::operator()(), libMesh::LinearPartitioner::partition_range(), libMesh::MetisPartitioner::partition_range(), libMesh::SFCPartitioner::partition_range(), libMesh::Partitioner::partition_unpartitioned_elements(), libMesh::LaspackMatrix< T >::pos(), libMesh::Elem::positive_face_orientation(), OverlappingFunctorTest::run_coupling_functor_test(), libMesh::FE< Dim, LAGRANGE_VEC >::shape_deriv(), libMesh::FE< Dim, LAGRANGE_VEC >::shape_second_deriv(), libMesh::StoredRange< iterator_type, object_type >::size(), libMesh::Parallel::BinSorter< KeyType, IdxType >::sizeof_bin(), libMesh::StoredRange< iterator_type, object_type >::StoredRange(), MultiEvaluablePredTest::test(), DefaultCouplingTest::testCoupling(), EquationSystemsTest::testDisableDefaultGhosting(), PartitionerTest< PartitionerSubclass, MeshClass >::testPartition(), CheckpointIOTest::testSplitter(), libMesh::TetGenMeshInterface::triangulate_conformingDelaunayMesh_carvehole(), libMesh::Poly2TriTriangulator::triangulate_current_points(), NonManifoldGhostingFunctorTest::verify_send_list_entries_helper(), libMesh::ExodusII_IO::write_element_data_from_discontinuous_nodal_data(), libMesh::ExodusII_IO_Helper::write_element_values_element_major(), libMesh::Nemesis_IO_Helper::write_exodus_initialization_info(), libMesh::Nemesis_IO_Helper::write_nodal_solution(), and libMesh::VariationalMeshSmoother::writegr().

{
  Point cent(0.8, 0.9);
  return ((p-cent).norm() - radius);
}

integrand()

Real integrand

(

const Point &

p

)

Definition at line 57 of file subdomains_ex3.C.

References distance().

Referenced by integrate_function().

{
  return (distance(p) < 0) ? 10. : 1.;
}

integrate_function()

void integrate_function

(

const MeshBase &

mesh

)

Definition at line 121 of file subdomains_ex3.C.

References libMesh::FEGenericBase< OutputType >::build(), libMesh::ParallelObject::comm(), distance(), libMesh::FIRST, libMesh::QComposite< QSubCell >::init(), integrand(), libMesh::LAGRANGE, libMesh::libmesh_ignore(), mesh, libMesh::MeshBase::mesh_dimension(), libMesh::out, libMesh::pi, radius, libMesh::Real, and TIMPI::Communicator::sum().

Referenced by main().

{
#if defined(LIBMESH_HAVE_TRIANGLE) && defined(LIBMESH_HAVE_TETGEN)

  std::vector<Real> vertex_distance;

  QComposite<QGauss> qrule (mesh.mesh_dimension(), FIRST);
  //QGauss qrule (mesh.mesh_dimension(), FIRST);

  std::unique_ptr<FEBase> fe (FEBase::build (mesh.mesh_dimension(), FEType (FIRST, LAGRANGE)));

  Real int_val=0.;

  const std::vector<Point> & q_points = fe->get_xyz();
  const std::vector<Real>  & JxW      = fe->get_JxW();

  for (const auto & elem : mesh.active_local_element_ptr_range())
    {
      vertex_distance.clear();

      for (unsigned int v=0; v<elem->n_vertices(); v++)
        vertex_distance.push_back (distance(elem->point(v)));

      qrule.init (*elem, vertex_distance);

      fe->reinit (elem,
                  &(qrule.get_points()),
                  &(qrule.get_weights()));


      // TODO:  would it be valuable to have the composite quadrature rule sort
      // from smallest to largest JxW value to help prevent
      // ... large + small + large + large + small ...
      // type truncation errors?
      for (std::size_t qp=0; qp<q_points.size(); qp++)
        int_val += JxW[qp] * integrand(q_points[qp]);
    }

  mesh.comm().sum (int_val);

  libMesh::out << "\n***********************************\n"
               << " int_val   = " << int_val << std::endl
               << " exact_val = " <<  1*(2*2 - radius*radius*pi) + 10.*(radius*radius*pi)
               << "\n***********************************\n"
               << std::endl;
#else
  libmesh_ignore(mesh);
#endif
}

main()

int main	(	int	argc,
		char **	argv
	)

Definition at line 65 of file subdomains_ex3.C.

References libMesh::command_line_next(), dim, libMesh::TriangleWrapper::init(), integrate_function(), mesh, libMesh::MeshBase::print_info(), libMesh::MeshBase::read(), and libMesh::MeshRefinement::uniformly_refine().

{
  // Initialize libMesh and any dependent libraries, like in example 2.
  LibMeshInit init (argc, argv);

  // This example requires Adaptive Mesh Refinement support - although
  // it only refines uniformly, the refinement code used is the same
  // underneath.  It also requires libmesh support for Triangle and
  // Tetgen, which means that libmesh must be configured with
  // --disable-strict-lgpl for this example to run.
#if !defined(LIBMESH_HAVE_TRIANGLE) || !defined(LIBMESH_HAVE_TETGEN) || !defined(LIBMESH_ENABLE_AMR)
  libmesh_example_requires(false, "--disable-strict-lgpl --enable-amr");
#else

  // Skip this 2D example if libMesh was compiled as 1D-only.
  libmesh_example_requires(2 <= LIBMESH_DIM, "2D support");

  // Read the mesh from file.  This is the coarse mesh that will be used
  // in example 10 to demonstrate adaptive mesh refinement.  Here we will
  // simply read it in and uniformly refine it 5 times before we compute
  // with it.
  Mesh mesh(init.comm());

  {
    const unsigned int dim =
      libMesh::command_line_next("-d", 2);

    if (dim == 3)
      std::cout << "Running in 3D" << std::endl;

    mesh.read ((dim==2) ? "mesh.xda" : "hybrid_3d.xda");
  }

  // Create a MeshRefinement object to handle refinement of our mesh.
  // This class handles all the details of mesh refinement and coarsening.
  MeshRefinement mesh_refinement (mesh);

  // Uniformly refine the mesh, by default 4 times.
  const int n_refinements =
    libMesh::command_line_next("-n_refinements", 4);

  mesh_refinement.uniformly_refine (n_refinements);

  // Print information about the mesh to the screen.
  mesh.print_info();

  // integrate the desired function
  integrate_function (mesh);

  // All done.
  return 0;
#endif
}

Variable Documentation

radius

const Real radius = 0.5

Definition at line 49 of file subdomains_ex3.C.

Referenced by distance(), integrate_function(), libMesh::InfFE< Dim, T_radial, T_map >::reinit(), MeshTriangulationTest::testTriangleHoleArea(), MeshTriangulationTest::testTriangleHoleContains(), and MeshTriangulationTest::testTriangulatorRoundHole().