Assign unique numbers to GMSH elements.

GMSH will not properly load information from a .msh file if some
element (geometry element, as in line, face, quadrilateral, hexahedron)
indices are repeated.

Partially addresses issue #814.

diff --git a/include/deal.II/grid/grid_out.h b/include/deal.II/grid/grid_out.h
index bd939571a4bb6fe009f11ab41d23b772688e0818..79a66489650f403b136e61eb887d53303fe0ae2d 100644 (file)
--- a/include/deal.II/grid/grid_out.h
+++ b/include/deal.II/grid/grid_out.h
@@ -1302,8 +1302,18 @@ private:
    * printed which are on the boundary and which have a boundary indicator not
    * equal to zero, since the latter is the default for boundary faces.
    *
-   * Since cells and faces are continuously numbered, the @p starting_index
-   * for the numbering of the faces is passed also.
+   * Since, in GMSH, geometric elements are continuously numbered, this
+   * function requires a parameter @p next_element_index providing the next
+   * geometric element number. This index should have a numerical value equal
+   * to one more than the index previously used to write a geometric element
+   * to @p out.
+   *
+   * @returns The next unused geometric element index.
+   *
+   * @warning @p next_element_index should be (at least) one larger than the
+   * current number of triangulation elements (lines, cells, faces) that have
+   * been written to @p out. GMSH will not load the saved file correctly if
+   * there are repeated indices.
    *
    * This function unfortunately can not be included in the regular @p
    * write_msh function, since it needs special treatment for the case
@@ -1313,26 +1323,30 @@ private:
    * compiling the function for <tt>dim==1</tt>. Bad luck.
    */
   template <int dim, int spacedim>
-  void write_msh_faces (const Triangulation<dim,spacedim> &tria,
-                        const unsigned int        starting_index,
-                        std::ostream             &out) const;
+  unsigned int
+  write_msh_faces (const Triangulation<dim,spacedim> &tria,
+                   const unsigned int                 next_element_index,
+                   std::ostream                      &out) const;
 
   /**
    * Declaration of the specialization of above function for 1d. Does nothing.
    */
-  void write_msh_faces (const Triangulation<1,1> &tria,
-                        const unsigned int      starting_index,
-                        std::ostream           &out) const;
+  unsigned int
+  write_msh_faces (const Triangulation<1,1>      &tria,
+                   const unsigned int             next_element_index,
+                   std::ostream                  &out) const;
   /**
    * Declaration of the specialization of above function for 1d, 2sd. Does
    * nothing.
    */
-  void write_msh_faces (const Triangulation<1,2> &tria,
-                        const unsigned int      starting_index,
-                        std::ostream           &out) const;
-  void write_msh_faces (const Triangulation<1,3> &tria,
-                        const unsigned int      starting_index,
-                        std::ostream           &out) const;
+  unsigned int
+  write_msh_faces (const Triangulation<1,2>      &tria,
+                   const unsigned int             next_element_index,
+                   std::ostream                  &out) const;
+  unsigned int
+  write_msh_faces (const Triangulation<1,3>      &tria,
+                   const unsigned int             next_element_index,
+                   std::ostream                  &out) const;
 
 
 
@@ -1341,8 +1355,18 @@ private:
    * printed which are on the boundary and which have a boundary indicator not
    * equal to zero, since the latter is the default for boundary faces.
    *
-   * Since cells and faces are continuously numbered, the @p starting_index
-   * for the numbering of the lines is passed also.
+   * Since, in GMSH, geometric elements are continuously numbered, this
+   * function requires a parameter @p next_element_index providing the next
+   * geometric element number. This index should have a numerical value equal
+   * to one more than the index previously used to write a geometric element
+   * to @p out.
+   *
+   * @returns The next unused geometric element index.
+   *
+   * @warning @p next_element_index should be (at least) one larger than the
+   * current number of triangulation elements (lines, cells, faces) that have
+   * been written to @p out. GMSH will not load the saved file correctly if
+   * there are repeated indices.
    *
    * This function unfortunately can not be included in the regular @p
    * write_msh function, since it needs special treatment for the case
@@ -1352,40 +1376,46 @@ private:
    * when compiling the function for <tt>dim==1/2</tt>. Bad luck.
    */
   template <int dim, int spacedim>
-  void write_msh_lines (const Triangulation<dim,spacedim> &tria,
-                        const unsigned int        starting_index,
-                        std::ostream             &out) const;
+  unsigned int
+  write_msh_lines (const Triangulation<dim,spacedim> &tria,
+                   const unsigned int                 next_element_index,
+                   std::ostream                      &out) const;
 
   /**
    * Declaration of the specialization of above function for 1d. Does nothing.
    */
-  void write_msh_lines (const Triangulation<1,1> &tria,
-                        const unsigned int      starting_index,
-                        std::ostream           &out) const;
+  unsigned int
+  write_msh_lines (const Triangulation<1,1>      &tria,
+                   const unsigned int             next_element_index,
+                   std::ostream                  &out) const;
 
   /**
    * Declaration of the specialization of above function for 1d, 2sd. Does
    * nothing.
    */
-  void write_msh_lines (const Triangulation<1,2> &tria,
-                        const unsigned int      starting_index,
-                        std::ostream           &out) const;
-  void write_msh_lines (const Triangulation<1,3> &tria,
-                        const unsigned int      starting_index,
-                        std::ostream           &out) const;
+  unsigned int
+  write_msh_lines (const Triangulation<1,2>      &tria,
+                   const unsigned int             next_element_index,
+                   std::ostream                  &out) const;
+  unsigned int
+  write_msh_lines (const Triangulation<1,3>      &tria,
+                   const unsigned int             next_element_index,
+                   std::ostream                  &out) const;
   /**
    * Declaration of the specialization of above function for 2d. Does nothing.
    */
-  void write_msh_lines (const Triangulation<2,2> &tria,
-                        const unsigned int      starting_index,
-                        std::ostream           &out) const;
+  unsigned int
+  write_msh_lines (const Triangulation<2,2>      &tria,
+                   const unsigned int             next_element_index,
+                   std::ostream                  &out) const;
   /**
    * Declaration of the specialization of above function for 2d, 3sd. Does
    * nothing.
    */
-  void write_msh_lines (const Triangulation<2,3> &tria,
-                        const unsigned int      starting_index,
-                        std::ostream           &out) const;
+  unsigned int
+  write_msh_lines (const Triangulation<2,3>      &tria,
+                   const unsigned int             next_element_index,
+                   std::ostream                  &out) const;
 
   /**
    * Write the grid information about faces to @p out. Only those faces are

diff --git a/source/grid/grid_out.cc b/source/grid/grid_out.cc
index 3d1efd1d4a7d30c1fa64abd501a05ceb17fa8d4a..280558767e39ce71e2726aab0cbb70797d91cf13 100644 (file)
--- a/source/grid/grid_out.cc
+++ b/source/grid/grid_out.cc
@@ -1063,13 +1063,16 @@ void GridOut::write_msh (const Triangulation<dim, spacedim> &tria,
       out << '\n';
     }
 
-  // write faces and lines with
-  // non-zero boundary indicator
-  unsigned int next_index = tria.n_active_cells()+1;
+  // write faces and lines with non-zero boundary indicator
+  unsigned int next_element_index = tria.n_active_cells()+1;
   if (msh_flags.write_faces)
-    write_msh_faces (tria, next_index, out);
+    {
+      next_element_index = write_msh_faces (tria, next_element_index, out);
+    }
   if (msh_flags.write_lines)
-    write_msh_lines (tria, next_index, out);
+    {
+      next_element_index = write_msh_lines (tria, next_element_index, out);
+    }
 
   out << "$ENDELM\n";
 
@@ -2620,83 +2623,92 @@ unsigned int GridOut::n_boundary_lines (const Triangulation<dim, spacedim> &tria
 
 
 
-void GridOut::write_msh_faces (const Triangulation<1> &,
-                               const unsigned int,
-                               std::ostream &) const
+unsigned int
+GridOut::write_msh_faces (const Triangulation<1> &,
+                          const unsigned int next_element_index,
+                          std::ostream &) const
 {
-  return;
+  return next_element_index;
 }
 
 
-void GridOut::write_msh_faces (const Triangulation<1,2> &,
-                               const unsigned int,
-                               std::ostream &) const
+unsigned int
+GridOut::write_msh_faces (const Triangulation<1,2> &,
+                          const unsigned int next_element_index,
+                          std::ostream &) const
 {
-  return;
+  return next_element_index;
 }
 
-void GridOut::write_msh_faces (const Triangulation<1,3> &,
-                               const unsigned int,
-                               std::ostream &) const
+unsigned int
+GridOut::write_msh_faces (const Triangulation<1,3> &,
+                          const unsigned int next_element_index,
+                          std::ostream &) const
 {
-  return;
+  return next_element_index;
 }
 
 
-void GridOut::write_msh_lines (const Triangulation<1> &,
-                               const unsigned int,
-                               std::ostream &) const
+unsigned int
+GridOut::write_msh_lines (const Triangulation<1> &,
+                          const unsigned int next_element_index,
+                          std::ostream &) const
 {
-  return;
+  return next_element_index;
 }
 
-void GridOut::write_msh_lines (const Triangulation<1,2> &,
-                               const unsigned int,
-                               std::ostream &) const
+unsigned int
+GridOut::write_msh_lines (const Triangulation<1,2> &,
+                          const unsigned int next_element_index,
+                          std::ostream &) const
 {
-  return;
+  return next_element_index;
 }
 
 
-void GridOut::write_msh_lines (const Triangulation<1,3> &,
-                               const unsigned int,
-                               std::ostream &) const
+unsigned int
+GridOut::write_msh_lines (const Triangulation<1,3> &,
+                          const unsigned int next_element_index,
+                          std::ostream &) const
 {
-  return;
+  return next_element_index;
 }
 
 
-void GridOut::write_msh_lines (const Triangulation<2> &,
-                               const unsigned int,
-                               std::ostream &) const
+unsigned int
+GridOut::write_msh_lines (const Triangulation<2> &,
+                          const unsigned int next_element_index,
+                          std::ostream &) const
 {
-  return;
+  return next_element_index;
 }
 
-void GridOut::write_msh_lines (const Triangulation<2,3> &,
-                               const unsigned int,
-                               std::ostream &) const
+unsigned int
+GridOut::write_msh_lines (const Triangulation<2,3> &,
+                          const unsigned int next_element_index,
+                          std::ostream &) const
 {
-  return;
+  return next_element_index;
 }
 
 
 
 
 template <int dim, int spacedim>
-void GridOut::write_msh_faces (const Triangulation<dim,spacedim> &tria,
-                               const unsigned int        starting_index,
-                               std::ostream             &out) const
+unsigned int
+GridOut::write_msh_faces (const Triangulation<dim,spacedim> &tria,
+                          const unsigned int                 next_element_index,
+                          std::ostream                      &out) const
 {
+  unsigned int current_element_index = next_element_index;
   typename Triangulation<dim,spacedim>::active_face_iterator face, endf;
-  unsigned int index=starting_index;
 
   for (face=tria.begin_active_face(), endf=tria.end_face();
        face != endf; ++face)
     if (face->at_boundary() &&
         (face->boundary_id() != 0))
       {
-        out << index << ' ';
+        out << current_element_index << ' ';
         switch (dim)
           {
           case 2:
@@ -2718,16 +2730,19 @@ void GridOut::write_msh_faces (const Triangulation<dim,spacedim> &tria,
               << face->vertex_index(GeometryInfo<dim-1>::ucd_to_deal[vertex])+1;
         out << '\n';
 
-        ++index;
+        ++current_element_index;
       }
+  return current_element_index;
 }
 
 
 template <int dim, int spacedim>
-void GridOut::write_msh_lines (const Triangulation<dim, spacedim> &tria,
-                               const unsigned int        starting_index,
-                               std::ostream             &out) const
+unsigned int
+GridOut::write_msh_lines (const Triangulation<dim,spacedim> &tria,
+                          const unsigned int                 next_element_index,
+                          std::ostream                      &out) const
 {
+  unsigned int current_element_index = next_element_index;
   // save the user flags for lines so
   // we can use these flags to track
   // which ones we've already taken
@@ -2739,7 +2754,6 @@ void GridOut::write_msh_lines (const Triangulation<dim, spacedim> &tria,
   .clear_user_flags_line ();
 
   typename Triangulation<dim, spacedim>::active_cell_iterator cell, endc;
-  unsigned int index=starting_index;
 
   for (cell=tria.begin_active(), endc=tria.end();
        cell != endc; ++cell)
@@ -2750,7 +2764,7 @@ void GridOut::write_msh_lines (const Triangulation<dim, spacedim> &tria,
           &&
           (cell->line(l)->user_flag_set() == false))
         {
-          out << index << " 1 ";
+          out << current_element_index << " 1 ";
           out << static_cast<unsigned int>(cell->line(l)->boundary_id())
               << ' '
               << static_cast<unsigned int>(cell->line(l)->boundary_id())
@@ -2764,7 +2778,7 @@ void GridOut::write_msh_lines (const Triangulation<dim, spacedim> &tria,
           // move on to the next line
           // but mark the current one
           // as taken care of
-          ++index;
+          ++current_element_index;
           cell->line(l)->set_user_flag();
         }
 
@@ -2772,6 +2786,8 @@ void GridOut::write_msh_lines (const Triangulation<dim, spacedim> &tria,
   // flags for the lines
   const_cast<dealii::Triangulation<dim,spacedim>&>(tria)
   .load_user_flags_line (line_flags);
+
+  return current_element_index;
 }
 
 

diff --git a/tests/grid/grid_out_04.output b/tests/grid/grid_out_04.output
index 5403b23775acae197f2bfeafb8a9fd8c0eafa4e2..8c48ef77eec472b7e81a00dfb59e42d80ee351ac 100644 (file)
--- a/tests/grid/grid_out_04.output
+++ b/tests/grid/grid_out_04.output
@@ -27,5 +27,5 @@ $ELM
 3
 1 5 0 0 8 1 2 6 5 3 4 8 7 
 2 3 2 2 4 5 6 8 7
-2 1 1 1 2  1 3
+3 1 1 1 2  1 3
 $ENDELM