cell_inf_hex.c

一个用来实现偏微分方程中网格的计算库

// $Id: cell_inf_hex.C 2789 2008-04-13 02:24:40Z roystgnr $

// The libMesh Finite Element Library.
// Copyright (C) 2002-2007  Benjamin S. Kirk, John W. Peterson
  
// 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_config.h"

#ifdef ENABLE_INFINITE_ELEMENTS


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

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




// ------------------------------------------------------------
// InfHex class member functions
unsigned int InfHex::key (const unsigned int s) const
{
  libmesh_assert (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));
    }

  // We'll never get here.
  libmesh_error();
 return 0;
}



AutoPtr<DofObject> InfHex::side (const unsigned int i) const
{
  libmesh_assert (i < this->n_sides());

  /*
   *Think of a unit cube: (-1,1) x (-1,1)x (-1,1),
   * with (in general) the normals pointing outwards
   */
  switch (i)
    {
    case 0:  // the face at z = -1
      // the base, where the infinite element couples to conventional
      // elements
      {  
        Elem* face = new Quad4;
        AutoPtr<DofObject> ap_face(face);

	/*
	 * 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->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);

	return ap_face;
      }

    case 1:  // the face at y = -1
      // this face connects to another infinite element
      {
        Elem* face = new InfQuad4;
        AutoPtr<DofObject> ap_face(face);

	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);
	
	return ap_face;
      }

    case 2:  // the face at x = 1
      // this face connects to another infinite element
      {
        Elem* face = new InfQuad4;
        AutoPtr<DofObject> ap_face(face);
	//AutoPtr<Elem> 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);

	return ap_face;
      }

    case 3: // the face at y = 1
      // this face connects to another infinite element
      {
        Elem* face = new InfQuad4;
        AutoPtr<DofObject> ap_face(face);
	//AutoPtr<Elem> 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);
	
	return ap_face;
      }

    case 4: // the face at x = -1
      // this face connects to another infinite element
      {  
        Elem* face = new InfQuad4;
        AutoPtr<DofObject> ap_face(face);
	//AutoPtr<Elem> 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);

	return ap_face;
      }

    default:
      {
	libmesh_error();
	AutoPtr<DofObject> ap(NULL);  return ap;
      }
    }

  // We'll never get here.
  libmesh_error();
  AutoPtr<DofObject> ap(NULL);  return ap;
}



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

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



Real InfHex::quality (const ElemQuality q) const
{
  switch (q)
    {
      
      /**
       * Compue the min/max diagonal ratio.
       * Source: CUBIT User's Manual.
       *
       * For infinite elements, we just only compute
       * the diagonal in the face...
       * Don't know whether this makes sense,
       * but should be a feasible way.
       */
    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 (max != 0.0);
	
	return min / max;

	break;
      }

      /**
       * Minimum ratio of lengths derived from opposite edges.
       * Source: CUBIT User's Manual.
       *
       * For IFEMs, do this only for the base face...
       * Does this make sense?
       */
    case TAPER:
      {

	/**
	 * Compute the side lengths.
	 */
	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;
      }


      /**
       * Minimum edge length divided by max diagonal length.
       * Source: CUBIT User's Manual.
       *
       * And again, we mess around a bit, for the IFEMs...
       * Do this only for the base.
       */
    case STRETCH:
      {
	/**
	 * Should this be a sqrt2, when we do this for the base only?
	 */
	const Real sqrt3 = 1.73205080756888;

	/**
	 * Compute the maximum diagonal in the base.
	 */
	const Real d02 = this->length(0,2);
	const Real d13 = this->length(1,3);
	const Real max_diag = std::max(d02, d13);

	libmesh_assert ( max_diag != 0.0 );

	/**
	 * Compute the minimum edge length in the base.
	 */
	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 ;
	break;
      }

      
      /**
       * I don't know what to do for this metric. 
       * Maybe the base class knows...
       */
    default:
      {
	return Elem::quality(q);
      }
    }

    
    // Will never get here...
    libmesh_error();
    return 0.;
}



std::pair<Real, Real> InfHex::qual_bounds (const ElemQuality) const
{
  std::cerr << "ERROR: Not implemented." << std::endl;
  libmesh_error();

  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:
      std::cout << "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
};




#endif // ifdef ENABLE_INFINITE_ELEMENTS