face_inf_quad4.h

一个用来实现偏微分方程中网格的计算库

// $Id: face_inf_quad4.h 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


#ifndef __inf_quad4_h__
#define __inf_quad4_h__


#include "libmesh_config.h"
#ifdef ENABLE_INFINITE_ELEMENTS

// C++ includes


// Local includes
#include "face_inf_quad.h"



/**
 * The \p INFQUAD4 is an infinite element in 2D composed of 4 nodes.
 * It is numbered like this:
   \verbatim
             2           3
   INFQUAD4: o           o   closer to infinity
             |           |
             |           |
             |           |  
             |           |
             |           |
             o-----------o   base side
             0           1
   \endverbatim
 */
// ------------------------------------------------------------
// InfQuad4 class definition
class InfQuad4 : public InfQuad
{
public:

  /**
   * Constructor.  By default this element has no parent.
   */
  InfQuad4 (Elem* p=NULL) :
    InfQuad(InfQuad4::n_nodes(), p) {}

  /**
   * Constructor.  Explicitly specifies the number of
   * nodes and neighbors for which storage will be allocated.
   */
  InfQuad4 (const unsigned int nn,
	    const unsigned int ns,
	    Elem* p) :
    InfQuad(nn, ns, p) {}
  
  /**
   * @returns 4
   */
  unsigned int n_nodes() const { return 4; }

  /**
   * @returns \p INFQUAD4 
   */
  ElemType type () const { return INFQUAD4; }
  
  /**
   * @returns 1
   */
  unsigned int n_sub_elem() const { return 1; }
  
  /**
   * @returns true iff the specified (local) node number is a vertex.
   */
  virtual bool is_vertex(const unsigned int i) const;

  /**
   * @returns true iff the specified (local) node number is an edge.
   */
  virtual bool is_edge(const unsigned int i) const;

  /**
   * @returns true iff the specified (local) node number is a face.
   */
  virtual bool is_face(const unsigned int i) const;
  
  /*
   * @returns true iff the specified (local) node number is on the
   * specified side
   */
  virtual bool is_node_on_side(const unsigned int n,
			       const unsigned int s) const;
  
  /*
   * @returns true iff the specified (local) node number is on the
   * specified edge (== is_node_on_side in 2D)
   */
  virtual bool is_node_on_edge(const unsigned int n,
			       const unsigned int e) const
  { return this->is_node_on_side(n,e); }
  
  /**
   * @returns \p FIRST
   */
  Order default_order() const { return FIRST; }
  
  /**
   * Creates and returns an \p Edge2 for the base side, and an \p InfEdge2 for
   * the sides 1, 2.
   */
  AutoPtr<Elem> build_side (const unsigned int i,
			    bool proxy) const;
/*    {  */
/*     // side() returns an AutoPtr to a DofObject, hence need to cast to Elem* */
/*     AutoPtr<DofObject> ap_dof_object(this->side(i)); */
/*     Elem* side = dynamic_cast<Elem*>(ap_dof_object.release()); */
/*     libmesh_assert(side); // libmesh_assert that the cast was successful */
    
/*     AutoPtr<Elem> ap(side); */
/*     return ap; */
/*   } */

  virtual void connectivity(const unsigned int sf,
			    const IOPackage iop,
			    std::vector<unsigned int>& conn) const;

//   void tecplot_connectivity(const unsigned int sf,
// 			    std::vector<unsigned int>& conn) const;
  
//   void vtk_connectivity(const unsigned int sc,
// 			std::vector<unsigned int>*conn = NULL) const;
  
//   unsigned int vtk_element_type (const unsigned int) const
//   { return 9; }
  
  /**
   * @returns \p true when this element contains the point
   * \p p.  Customized for this \p InfQuad4, since knowledge
   * about the envelope can help avoiding slightly more 
   * expensive computations.
   */
  bool contains_point (const Point& p) const;

  /**
   * This maps the \f$ j^{th} \f$ node of the \f$ i^{th} \f$ side to
   * element node numbers.
   */
  static const unsigned int side_nodes_map[3][2];

  
protected:
  
  
#ifdef ENABLE_AMR
  
  /**
   * Matrix used to create the elements children.
   */
  float embedding_matrix (const unsigned int i,
			  const unsigned int j,
			  const unsigned int k) const
  { return _embedding_matrix[i][j][k]; }

  /**
   * Matrix that computes new nodal locations/solution values
   * from current nodes/solution.
   */
  static const float _embedding_matrix[2][4][4];
  
#endif
    
};
  

#endif // ifdef ENABLE_INFINITE_ELEMENTS

#endif