face_tri.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

// C++ includes

// Local includes
#include "libmesh/face_tri.h"
#include "libmesh/edge_edge2.h"

namespace libMesh
{





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

  switch (s)
    {
    case 0:
      return
        this->compute_key (this->node(0),
                           this->node(1));

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

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

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



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

  Elem* edge = new Edge2;

  switch (i)
    {
    case 0:
      {
        edge->set_node(0) = this->get_node(0);
        edge->set_node(1) = this->get_node(1);
        break;
      }
    case 1:
      {
        edge->set_node(0) = this->get_node(1);
        edge->set_node(1) = this->get_node(2);
        break;
      }
    case 2:
      {
        edge->set_node(0) = this->get_node(2);
        edge->set_node(1) = this->get_node(0);
        break;
      }
    default:
      libmesh_error_msg("Invalid side i = " << i);
    }

  return UniquePtr<Elem>(edge);
}



bool Tri::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 (c == s || c == (s+1)%3);
}



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

    case DISTORTION:
    case STRETCH:
      {
        const Node* p1 = this->get_node(0);
        const Node* p2 = this->get_node(1);
        const Node* p3 = this->get_node(2);

        Point v1 = (*p2) - (*p1);
        Point v2 = (*p3) - (*p1);
        Point v3 = (*p3) - (*p2);
        const Real l1 = v1.size();
        const Real l2 = v2.size();
        const Real l3 = v3.size();

        // if one length is 0, quality is quite bad!
        if ((l1 <=0.) || (l2 <= 0.) || (l3 <= 0.))
          return 0.;

        const Real s1 = std::sin(std::acos(v1*v2/l1/l2)/2.);
        v1 *= -1;
        const Real s2 = std::sin(std::acos(v1*v3/l1/l3)/2.);
        const Real s3 = std::sin(std::acos(v2*v3/l2/l3)/2.);

        return 8. * s1 * s2 * s3;

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

  return Elem::quality(q);

}






std::pair<Real, Real> Tri::qual_bounds (const ElemQuality q) const
{
  std::pair<Real, Real> bounds;

  switch (q)
    {

    case MAX_ANGLE:
      bounds.first  = 60.;
      bounds.second = 90.;
      break;

    case MIN_ANGLE:
      bounds.first  = 30.;
      bounds.second = 60.;
      break;

    case CONDITION:
      bounds.first  = 1.;
      bounds.second = 1.3;
      break;

    case JACOBIAN:
      bounds.first  = 0.5;
      bounds.second = 1.155;
      break;

    case SIZE:
    case SHAPE:
      bounds.first  = 0.25;
      bounds.second = 1.;
      break;

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

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

  return bounds;
}

} // namespace libMesh