Line data    Source code

       1             : // The libMesh Finite Element Library.
       2             : // Copyright (C) 2002-2025 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner
       3             : 
       4             : // This library is free software; you can redistribute it and/or
       5             : // modify it under the terms of the GNU Lesser General Public
       6             : // License as published by the Free Software Foundation; either
       7             : // version 2.1 of the License, or (at your option) any later version.
       8             : 
       9             : // This library is distributed in the hope that it will be useful,
      10             : // but WITHOUT ANY WARRANTY; without even the implied warranty of
      11             : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12             : // Lesser General Public License for more details.
      13             : 
      14             : // You should have received a copy of the GNU Lesser General Public
      15             : // License along with this library; if not, write to the Free Software
      16             : // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
      17             : 
      18             : 
      19             : 
      20             : #ifndef LIBMESH_GMSH_IO_H
      21             : #define LIBMESH_GMSH_IO_H
      22             : 
      23             : // Local includes
      24             : #include "libmesh/libmesh_common.h"
      25             : #include "libmesh/mesh_input.h"
      26             : #include "libmesh/mesh_output.h"
      27             : 
      28             : // C++ includes
      29             : #include <cstddef>
      30             : 
      31             : namespace libMesh
      32             : {
      33             : 
      34             : // Forward declarations
      35             : class MeshBase;
      36             : 
      37             : 
      38             : 
      39             : /**
      40             :  * \brief Reading and writing meshes in the Gmsh format.
      41             :  *
      42             :  * For a full description of the Gmsh format and to obtain the
      43             :  * GMSH software see
      44             :  * <a href="http://http://www.geuz.org/gmsh/">the Gmsh home page</a>
      45             :  *
      46             :  * \author John W. Peterson
      47             :  * \date 2004, 2014
      48             :  * \author Martin Luthi
      49             :  * \date 2005
      50             :  */
      51             : class GmshIO : public MeshInput<MeshBase>,
      52             :                public MeshOutput<MeshBase>
      53             : {
      54             : public:
      55             : 
      56             :   /**
      57             :    * Constructor.  Takes a non-const Mesh reference which it
      58             :    * will fill up with elements via the read() command.
      59             :    */
      60             :   explicit
      61             :   GmshIO (MeshBase & mesh);
      62             : 
      63             :   /**
      64             :    * Constructor.  Takes a reference to a constant mesh object.
      65             :    * This constructor will only allow us to write the mesh.
      66             :    */
      67             :   explicit
      68             :   GmshIO (const MeshBase & mesh);
      69             : 
      70             :   /**
      71             :    * Reads in a mesh in the Gmsh *.msh format from the ASCII file
      72             :    * given by name.
      73             :    *
      74             :    * \note The user is responsible for calling Mesh::prepare_for_use()
      75             :    * after reading the mesh and before using it.
      76             :    *
      77             :    * The physical group names defined in the Gmsh-file are stored, depending
      78             :    * on the element dimension, as either subdomain name or as side name. The
      79             :    * IDs of the former can be retrieved by using the MeshBase::get_id_by_name
      80             :    * method; the IDs of the latter can be retrieved by using the
      81             :    * MeshBase::get_boundary_info and the BoundaryInfo::get_id_by_name methods.
      82             :    */
      83             :   virtual void read (const std::string & name) override;
      84             : 
      85             :   /**
      86             :    * This method implements writing a mesh to a specified file
      87             :    * in the Gmsh *.msh format.
      88             :    */
      89             :   virtual void write (const std::string & name) override;
      90             : 
      91             :   /**
      92             :    * Bring in base class functionality for name resolution and to
      93             :    * avoid warnings about hidden overloaded virtual functions.
      94             :    */
      95             :   using MeshOutput<MeshBase>::write_nodal_data;
      96             : 
      97             :   /**
      98             :    * This method implements writing a mesh with nodal data to a
      99             :    * specified file where the nodal data and variable names are provided.
     100             :    */
     101             :   virtual void write_nodal_data (const std::string &,
     102             :                                  const std::vector<Number> &,
     103             :                                  const std::vector<std::string> &) override;
     104             : 
     105             :   /**
     106             :    * Flag indicating whether or not to write a binary file.  While binary
     107             :    * files may end up being smaller than equivalent ASCII files, they will
     108             :    * almost certainly take longer to write.  The reason for this is that
     109             :    * the ostream::write() function which is used to write "binary" data to
     110             :    * streams, only takes a pointer to char as its first argument.  This means
     111             :    * if you want to write anything other than a buffer of chars, you first
     112             :    * have to use a strange memcpy hack to get the data into the desired format.
     113             :    * See the templated to_binary_stream() function below.
     114             :    */
     115             :   bool & binary ();
     116             : 
     117             :   /**
     118             :    * Access to the flag which controls whether boundary elements are
     119             :    * written to the Mesh file.
     120             :    */
     121             :   bool & write_lower_dimensional_elements ();
     122             : 
     123             : private:
     124             :   /**
     125             :    * Implementation of the read() function.  This function
     126             :    * is called by the public interface function and implements
     127             :    * reading the file.
     128             :    */
     129             :   void read_mesh (std::istream & in);
     130             : 
     131             :   /**
     132             :    * This method implements writing a mesh to a
     133             :    * specified file.  This will write an ASCII *.msh file.
     134             :    */
     135             :   void write_mesh (std::ostream & out);
     136             : 
     137             :   /**
     138             :    * This method implements writing a mesh with nodal data to a specified file
     139             :    * where the nodal data and variable names are optionally provided.  This
     140             :    * will write an ASCII or binary *.pos file, depending on the binary flag.
     141             :    */
     142             :   void write_post (const std::string &,
     143             :                    const std::vector<Number> * = nullptr,
     144             :                    const std::vector<std::string> * = nullptr);
     145             : 
     146             :   /**
     147             :    * Flag to write binary data.
     148             :    */
     149             :   bool _binary;
     150             : 
     151             :   /**
     152             :    * If true, lower-dimensional elements based on the boundary
     153             :    * conditions get written to the output file.
     154             :    */
     155             :   bool _write_lower_dimensional_elements;
     156             : 
     157             :   /**
     158             :    * Defines mapping from libMesh element types to Gmsh element types or vice-versa.
     159             :    */
     160      201045 :   struct ElementDefinition
     161             :   {
     162        7854 :     ElementDefinition(ElemType type_in,
     163             :                       unsigned gmsh_type_in,
     164             :                       unsigned dim_in,
     165        7854 :                       unsigned nnodes_in) :
     166      262905 :       type(type_in),
     167      262905 :       gmsh_type(gmsh_type_in),
     168      262905 :       dim(dim_in),
     169      278613 :       nnodes(nnodes_in)
     170        7854 :     {}
     171             : 
     172             :     ElemType type;
     173             :     unsigned int gmsh_type;
     174             :     unsigned int dim;
     175             :     unsigned int nnodes;
     176             :     std::vector<unsigned int> nodes;
     177             :   };
     178             : 
     179             :   /**
     180             :    * struct which holds a map from Gmsh to libMesh element numberings
     181             :    * and vice-versa.
     182             :    */
     183             :   struct ElementMaps
     184             :   {
     185             :     // Helper function to add a (key, value) pair to both maps
     186      262224 :     void add_def(const ElementDefinition & eledef)
     187             :     {
     188      262224 :       out.emplace(eledef.type, eledef);
     189      262224 :       in.emplace(eledef.gmsh_type, eledef);
     190      262224 :     }
     191             : 
     192             :     std::map<ElemType, ElementDefinition> out;
     193             :     std::map<unsigned int, ElementDefinition> in;
     194             :   };
     195             : 
     196             :   /**
     197             :    * A static ElementMaps object that is built statically and used by
     198             :    * all instances of this class.
     199             :    */
     200             :   static ElementMaps _element_maps;
     201             : 
     202             :   /**
     203             :    * A static function used to construct the _element_maps struct,
     204             :    * statically.
     205             :    */
     206             :   static ElementMaps build_element_maps();
     207             : };
     208             : 
     209             : 
     210             : } // namespace libMesh
     211             : 
     212             : #endif // LIBMESH_GMSH_IO_H