cell_inf_hex.C

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// The libMesh Finite Element Library.
// Copyright (C) 2002-2014 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner

// This library is free software; you can 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.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.

// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

// Local includes
#include "libmesh/libmesh_config.h"

#ifdef LIBMESH_ENABLE_INFINITE_ELEMENTS


// C++ includes
#include <algorithm> // for std::min, std::max

// Local includes cont'd
#include "libmesh/cell_inf_hex.h"
#include "libmesh/cell_inf_hex8.h"
#include "libmesh/face_quad4.h"
#include "libmesh/face_inf_quad4.h"

namespace libMesh
{




// ------------------------------------------------------------
// InfHex class member functions
dof_id_type InfHex::key (const unsigned int s) const
{
  libmesh_assert_less (s, this->n_sides());

  switch (s)
    {
    case 0:  // the face at z = -1

      return
        this->compute_key (this->node(0),
                           this->node(1),
                           this->node(2),
                           this->node(3));

    case 1:  // the face at y = -1

      return
        this->compute_key (this->node(0),
                           this->node(1),
                           this->node(5),
                           this->node(4));

    case 2:  // the face at x = 1

      return
        this->compute_key (this->node(1),
                           this->node(2),
                           this->node(6),
                           this->node(5));

    case 3: // the face at y = 1

      return
        this->compute_key (this->node(2),
                           this->node(3),
                           this->node(7),
                           this->node(6));


    case 4: // the face at x = -1

      return
        this->compute_key (this->node(3),
                           this->node(0),
                           this->node(4),
                           this->node(7));

    default:
      libmesh_error_msg("Invalid side s = " << s);
    }

  libmesh_error_msg("We'll never get here!");
  return 0;
}



UniquePtr<Elem> InfHex::side (const unsigned int i) const
{
  libmesh_assert_less (i, this->n_sides());

  // To be returned wrapped in an UniquePtr
  Elem* face = NULL;

  // Think of a unit cube: (-1,1) x (-1,1) x (-1,1),
  // with (in general) the normals pointing outwards
  switch (i)
    {
      // the face at z = -1
      // the base, where the infinite element couples to conventional
      // elements
    case 0:
      {
        // Oops, here we are, claiming the normal of the face
        // elements point outwards -- and this is the exception:
        // For the side built from the base face,
        // the normal is pointing _into_ the element!
        // Why is that? - In agreement with build_side(),
        // which in turn _has_ to build the face in this
        // way as to enable the cool way \p InfFE re-uses \p FE.
        face = new Quad4;
        face->set_node(0) = this->get_node(0);
        face->set_node(1) = this->get_node(1);
        face->set_node(2) = this->get_node(2);
        face->set_node(3) = this->get_node(3);
        break;
      }

      // the face at y = -1
      // this face connects to another infinite element
    case 1:
      {
        face = new InfQuad4;
        face->set_node(0) = this->get_node(0);
        face->set_node(1) = this->get_node(1);
        face->set_node(2) = this->get_node(4);
        face->set_node(3) = this->get_node(5);
        break;
      }

      // the face at x = 1
      // this face connects to another infinite element
    case 2:
      {
        face = new InfQuad4;
        face->set_node(0) = this->get_node(1);
        face->set_node(1) = this->get_node(2);
        face->set_node(2) = this->get_node(5);
        face->set_node(3) = this->get_node(6);
        break;
      }

      // the face at y = 1
      // this face connects to another infinite element
    case 3:
      {
        face = new InfQuad4;
        face->set_node(0) = this->get_node(2);
        face->set_node(1) = this->get_node(3);
        face->set_node(2) = this->get_node(6);
        face->set_node(3) = this->get_node(7);
        break;
      }

      // the face at x = -1
      // this face connects to another infinite element
    case 4:
      {
        face = new InfQuad4;
        face->set_node(0) = this->get_node(3);
        face->set_node(1) = this->get_node(0);
        face->set_node(2) = this->get_node(7);
        face->set_node(3) = this->get_node(4);
        break;
      }

    default:
      libmesh_error_msg("Invalid side i = " << i);
    }

  return UniquePtr<Elem>(face);
}



bool InfHex::is_child_on_side(const unsigned int c,
                              const unsigned int s) const
{
  libmesh_assert_less (c, this->n_children());
  libmesh_assert_less (s, this->n_sides());

  return (s == 0 || c+1 == s || c == s%4);
}



bool InfHex::is_edge_on_side (const unsigned int e,
                              const unsigned int s) const
{
  libmesh_assert_less (e, this->n_edges());
  libmesh_assert_less (s, this->n_sides());

  return (is_node_on_side(InfHex8::edge_nodes_map[e][0],s) &&
          is_node_on_side(InfHex8::edge_nodes_map[e][1],s));
}




Real InfHex::quality (const ElemQuality q) const
{
  switch (q)
    {

    case DIAGONAL:
      {
        // Diagonal between node 0 and node 2
        const Real d02 = this->length(0,2);

        // Diagonal between node 1 and node 3
        const Real d13 = this->length(1,3);

        // Find the biggest and smallest diagonals
        const Real min = std::min(d02, d13);
        const Real max = std::max(d02, d13);

        libmesh_assert_not_equal_to (max, 0.0);

        return min / max;

        break;
      }

    case TAPER:
      {

        const Real d01 = this->length(0,1);
        const Real d12 = this->length(1,2);
        const Real d23 = this->length(2,3);
        const Real d03 = this->length(0,3);

        std::vector<Real> edge_ratios(2);

        // Bottom
        edge_ratios[8] = std::min(d01, d23) / std::max(d01, d23);
        edge_ratios[9] = std::min(d03, d12) / std::max(d03, d12);

        return *(std::min_element(edge_ratios.begin(), edge_ratios.end())) ;

        break;
      }


    case STRETCH:
      {
        const Real sqrt3 = 1.73205080756888;

        const Real d02 = this->length(0,2);
        const Real d13 = this->length(1,3);
        const Real max_diag = std::max(d02, d13);

        libmesh_assert_not_equal_to ( max_diag, 0.0 );

        std::vector<Real> edges(4);
        edges[0]  = this->length(0,1);
        edges[1]  = this->length(1,2);
        edges[2]  = this->length(2,3);
        edges[3]  = this->length(0,3);

        const Real min_edge = *(std::min_element(edges.begin(), edges.end()));
        return sqrt3 * min_edge / max_diag ;
      }


    default:
      return Elem::quality(q);
    }

  libmesh_error_msg("We'll never get here!");
  return 0.;
}



std::pair<Real, Real> InfHex::qual_bounds (const ElemQuality) const
{
  libmesh_not_implemented();

  std::pair<Real, Real> bounds;

  /*
    switch (q)
    {

    case ASPECT_RATIO:
    bounds.first  = 1.;
    bounds.second = 4.;
    break;

    case SKEW:
    bounds.first  = 0.;
    bounds.second = 0.5;
    break;

    case SHEAR:
    case SHAPE:
    bounds.first  = 0.3;
    bounds.second = 1.;
    break;

    case CONDITION:
    bounds.first  = 1.;
    bounds.second = 8.;
    break;

    case JACOBIAN:
    bounds.first  = 0.5;
    bounds.second = 1.;
    break;

    case DISTORTION:
    bounds.first  = 0.6;
    bounds.second = 1.;
    break;

    case TAPER:
    bounds.first  = 0.;
    bounds.second = 0.4;
    break;

    case STRETCH:
    bounds.first  = 0.25;
    bounds.second = 1.;
    break;

    case DIAGONAL:
    bounds.first  = 0.65;
    bounds.second = 1.;
    break;

    case SIZE:
    bounds.first  = 0.5;
    bounds.second = 1.;
    break;

    default:
    libMesh::out << "Warning: Invalid quality measure chosen." << std::endl;
    bounds.first  = -1;
    bounds.second = -1;
    }
  */

  return bounds;
}





const unsigned short int InfHex::_second_order_adjacent_vertices[8][2] =
  {
    { 0,  1}, // vertices adjacent to node 8
    { 1,  2}, // vertices adjacent to node 9
    { 2,  3}, // vertices adjacent to node 10
    { 0,  3}, // vertices adjacent to node 11

    { 4,  5}, // vertices adjacent to node 12
    { 5,  6}, // vertices adjacent to node 13
    { 6,  7}, // vertices adjacent to node 14
    { 4,  7}  // vertices adjacent to node 15
  };



const unsigned short int InfHex::_second_order_vertex_child_number[18] =
  {
    99,99,99,99,99,99,99,99, // Vertices
    0,1,2,0,                 // Edges
    0,1,2,0,0,               // Faces
    0                        // Interior
  };



const unsigned short int InfHex::_second_order_vertex_child_index[18] =
  {
    99,99,99,99,99,99,99,99, // Vertices
    1,2,3,3,                 // Edges
    5,6,7,7,2,               // Faces
    6                        // Interior
  };

} // namespace libMesh




#endif // ifdef LIBMESH_ENABLE_INFINITE_ELEMENTS