cell_inf_prism.C

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// The libMesh Finite Element Library.
// Copyright (C) 2002-2018 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

#include "libmesh/libmesh_config.h"

#ifdef LIBMESH_ENABLE_INFINITE_ELEMENTS

// Local includes
#include "libmesh/cell_inf_prism.h"
#include "libmesh/cell_inf_prism6.h"
#include "libmesh/face_tri3.h"
#include "libmesh/face_inf_quad4.h"
#include "libmesh/fe_type.h"
#include "libmesh/fe_interface.h"
#include "libmesh/enum_order.h"

namespace libMesh
{


// ------------------------------------------------------------
// InfPrism class static member initializations


// We need to require C++11...
const Real InfPrism::_master_points[12][3] =
  {
    {0, 0, 0},
    {1, 0, 0},
    {0, 1, 0},
    {0, 0, 1},
    {1, 0, 1},
    {0, 1, 1},
    {.5, 0, 0},
    {.5, .5, 0},
    {0, .5, 0},
    {.5, 0, 1},
    {.5, .5, 1},
    {0, .5, 1}
  };



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

  switch (s)
    {
    case 0: // the triangular face at z=-1, base face
      return this->compute_key (this->node_id(InfPrism6::side_nodes_map[s][0]),
                                this->node_id(InfPrism6::side_nodes_map[s][1]),
                                this->node_id(InfPrism6::side_nodes_map[s][2]));

    case 1: // the quad face at y=0
    case 2: // the other quad face
    case 3: // the quad face at x=0
      return this->compute_key (this->node_id(InfPrism6::side_nodes_map[s][0]),
                                this->node_id(InfPrism6::side_nodes_map[s][1]),
                                this->node_id(InfPrism6::side_nodes_map[s][2]),
                                this->node_id(InfPrism6::side_nodes_map[s][3]));

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



unsigned int InfPrism::which_node_am_i(unsigned int side,
                                       unsigned int side_node) const
{
  libmesh_assert_less (side, this->n_sides());

  // Never more than 4 nodes per side.
  libmesh_assert_less(side_node, 4);

  // Some sides have 3 nodes.
  libmesh_assert(side != 0 || side_node < 3);

  return InfPrism6::side_nodes_map[side][side_node];
}



std::unique_ptr<Elem> InfPrism::side_ptr (const unsigned int i)
{
  libmesh_assert_less (i, this->n_sides());

  std::unique_ptr<Elem> face;

  switch (i)
    {
    case 0: // the triangular face at z=-1, base face
      {
        face = libmesh_make_unique<Tri3>();
        break;
      }

    case 1: // the quad face at y=0
    case 2: // the other quad face
    case 3: // the quad face at x=0
      {
        face = libmesh_make_unique<InfQuad4>();
        break;
      }

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

  // Set the nodes
  for (unsigned n=0; n<face->n_nodes(); ++n)
    face->set_node(n) = this->node_ptr(InfPrism6::side_nodes_map[i][n]);

  return face;
}



void InfPrism::side_ptr (std::unique_ptr<Elem> & side,
                         const unsigned int i)
{
  libmesh_assert_less (i, this->n_sides());

  switch (i)
    {
      // the base face
    case 0:
      {
        if (!side.get() || side->type() != TRI3)
          {
            side = this->side_ptr(i);
            return;
          }
        break;
      }

      // connecting to another infinite element
    case 1:
    case 2:
    case 3:
    case 4:
      {
        if (!side.get() || side->type() != INFQUAD4)
          {
            side = this->side_ptr(i);
            return;
          }
        break;
      }

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

  side->subdomain_id() = this->subdomain_id();

  // Set the nodes
  for (auto n : side->node_index_range())
    side->set_node(n) = this->node_ptr(InfPrism6::side_nodes_map[i][n]);
}



bool InfPrism::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%3);
}



bool InfPrism::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(InfPrism6::edge_nodes_map[e][0],s) &&
          is_node_on_side(InfPrism6::edge_nodes_map[e][1],s));
}

bool InfPrism::contains_point (const Point & p, Real tol) const
{
  // For infinite elements with linear base interpolation:
  // make use of the fact that infinite elements do not
  // live inside the envelope.  Use a fast scheme to
  // check whether point \p p is inside or outside
  // our relevant part of the envelope.  Note that
  // this is not exclusive: only when the distance is less,
  // we are safe.  Otherwise, we cannot say anything. The
  // envelope may be non-spherical, the physical point may lie
  // inside the envelope, outside the envelope, or even inside
  // this infinite element.  Therefore if this fails,
  // fall back to the FEInterface::inverse_map()
  const Point my_origin (this->origin());

  // determine the minimal distance of the base from the origin
  // use norm_sq(), it is faster than norm() and produces
  // the same behavior. Shift my_origin to center first:
  Point pt0_o(this->point(0) - my_origin);
  Point pt1_o(this->point(1) - my_origin);
  Point pt2_o(this->point(2) - my_origin);
  const Real min_distance_sq = std::min(pt0_o.norm_sq(),
                                        std::min(pt1_o.norm_sq(),
                                                 pt2_o.norm_sq()));

  // work with 1% allowable deviation.  We can still fall
  // back to the InfFE::inverse_map()
  const Real conservative_p_dist_sq = 1.01 * (Point(p - my_origin).norm_sq());

  if (conservative_p_dist_sq < min_distance_sq)
    {
      // the physical point is definitely not contained in the element:
      return false;
    }

  // this captures the case that the point is not (almost) in the direction of the element.:
  // first, project the problem onto the unit sphere:
  Point p_o(p - my_origin);
  pt0_o /= pt0_o.norm();
  pt1_o /= pt1_o.norm();
  pt2_o /= pt2_o.norm();
  p_o /= p_o.norm();

  // now, check if it is in the projected face; by comparing the distance of
  // any point in the element to \p p with the largest distance between this point
  // to any other point in the element.
  if ((p_o - pt0_o).norm_sq() > std::max((pt0_o - pt1_o).norm_sq(), (pt0_o - pt2_o).norm_sq()) ||
      (p_o - pt1_o).norm_sq() > std::max((pt1_o - pt2_o).norm_sq(), (pt1_o - pt0_o).norm_sq()) ||
      (p_o - pt2_o).norm_sq() > std::max((pt2_o - pt0_o).norm_sq(), (pt2_o - pt1_o).norm_sq()) )
    {
      // the physical point is definitely not contained in the element
      return false;
    }


  // It seems that \p p is at least close to this element.
  //
  // Declare a basic FEType.  Will use default in the base,
  // and something else (not important) in radial direction.
  FEType fe_type(default_order());

  const Point mapped_point = FEInterface::inverse_map(dim(),
                                                      fe_type,
                                                      this,
                                                      p,
                                                      tol,
                                                      false);

  return FEInterface::on_reference_element(mapped_point, this->type(), tol);
}


} // namespace libMesh



#endif // ifdef LIBMESH_ENABLE_INFINITE_ELEMENTS