* code. We don't have an exact specification of the format, but the reader
* can read in several example files. If the reader does not grok your files,
* it should be fairly simple to extend it.
+ *
+ * <li> <tt>Gmsh mesh</tt> format: this format is used by the @p GMSH
+ * mesh generator (see http://www.geuz.org/gmsh/ ). The documentation
+ * in the @p GMSH manual explains how to generate meshes compatible with
+ * the deal.II library (i.e. quads rather than triangles).
* </ul>
*
*
* that class if you experience unexpected problems when reading grids
* through this class.
*
- * @author Wolfgang Bangerth, 1998, 2000
+ * @author Wolfgang Bangerth, 1998, 2000, Luca Heltai, 2004
*/
template <int dim>
class GridIn
*/
void read_xda (std::istream &);
+ /**
+ * Read grid data from an msh file.
+ */
+ void read_msh (std::istream &);
+
/**
* Exception
*/
int,
<< "The specified dimension " << arg1
<< " is not the same as that of the triangulation to be created.");
-
+
+ DeclException1 (ExcInvalidGMSHInput,
+ std::string,
+ << "The string <" << arg1 << "> is not recognized at the present"
+ << " position of a Gmsh Mesh file.");
+
+ DeclException1 (ExcGmshUnsupportedGeometry,
+ int,
+ << "The Element Identifier <" << arg1 << "> is not "
+ << "supported in the Deal.II Library.\n"
+ << "Supported elements are: \n"
+ << "ELM-TYPE\n"
+ << "1 Line (2 nodes, 1 edge).\n"
+ << "3 Quadrangle (4 nodes, 4 edges).\n"
+ << "5 Hexahedron (8 nodes, 12 edges, 6 faces).\n"
+ << "15 Point (1 node).");
private:
/**
* Store address of the triangulation to
+template <int dim>
+void GridIn<dim>::read_msh (std::istream &in)
+{
+ Assert (tria != 0, ExcNoTriangulationSelected());
+ AssertThrow (in, ExcIO());
+
+ unsigned int n_vertices;
+ unsigned int n_cells;
+ unsigned int dummy;
+ std::string line;
+
+ getline(in, line);
+
+ AssertThrow (line=="$NOD",
+ ExcInvalidGMSHInput(line));
+
+ in >> n_vertices;
+
+ std::vector<Point<dim> > vertices (n_vertices);
+ // set up mapping between numbering
+ // in msh-file (nod) and in the
+ // vertices vector
+ std::map<int,int> vertex_indices;
+
+ for (unsigned int vertex=0; vertex<n_vertices; ++vertex)
+ {
+ int vertex_number;
+ double x[3];
+
+ // read vertex
+ in >> vertex_number
+ >> x[0] >> x[1] >> x[2];
+
+ for (unsigned int d=0; d<dim; ++d)
+ vertices[vertex](d) = x[d];
+ // store mapping;
+ vertex_indices[vertex_number] = vertex;
+ };
+
+ // This is needed to flush the last
+ // new line
+ getline (in, line);
+
+ // Now read in next bit
+ getline (in, line);
+ AssertThrow (line=="$ENDNOD",
+ ExcInvalidGMSHInput(line));
+
+
+ getline (in, line);
+ AssertThrow (line=="$ELM",
+ ExcInvalidGMSHInput(line));
+
+ in >> n_cells;
+ // set up array of cells
+ std::vector<CellData<dim> > cells;
+ SubCellData subcelldata;
+
+ for (unsigned int cell=0; cell<n_cells; ++cell)
+ {
+ // note that since in the input
+ // file we found the number of
+ // cells at the top, there
+ // should still be input here,
+ // so check this:
+ AssertThrow (in, ExcIO());
+
+/*
+ $ENDNOD
+ $ELM
+ NUMBER-OF-ELEMENTS
+ ELM-NUMBER ELM-TYPE REG-PHYS REG-ELEM NUMBER-OF-NODES NODE-NUMBER-LIST
+ ...
+ $ENDELM
+*/
+
+ unsigned int cell_type;
+ unsigned int material_id;
+ unsigned int nod_num;
+
+ in >> dummy // ELM-NUMBER
+ >> cell_type // ELM-TYPE
+ >> material_id // REG-PHYS
+ >> dummy // reg_elm
+ >> nod_num;
+
+/* `ELM-TYPE'
+ defines the geometrical type of the N-th element:
+ `1'
+ Line (2 nodes, 1 edge).
+
+ `3'
+ Quadrangle (4 nodes, 4 edges).
+
+ `5'
+ Hexahedron (8 nodes, 12 edges, 6 faces).
+
+ `15'
+ Point (1 node).
+*/
+
+ if (((cell_type == 1) && (dim == 1)) ||
+ ((cell_type == 3) && (dim == 2)) ||
+ ((cell_type == 5) && (dim == 3)))
+ // found a cell
+ {
+ // allocate and read indices
+ cells.push_back (CellData<dim>());
+ for (unsigned int i=0; i<GeometryInfo<dim>::vertices_per_cell; ++i)
+ in >> cells.back().vertices[i];
+ cells.back().material_id = material_id;
+
+ // transform from ucd to
+ // consecutive numbering
+ for (unsigned int i=0; i<GeometryInfo<dim>::vertices_per_cell; ++i)
+ if (vertex_indices.find (cells.back().vertices[i]) != vertex_indices.end())
+ // vertex with this index exists
+ cells.back().vertices[i] = vertex_indices[cells.back().vertices[i]];
+ else
+ {
+ // no such vertex index
+ AssertThrow (false, ExcInvalidVertexIndex(cell, cells.back().vertices[i]));
+ cells.back().vertices[i] = -1;
+ };
+ }
+ else
+ if ((cell_type == 1) && ((dim == 2) || (dim == 3)))
+ // boundary info
+ {
+ subcelldata.boundary_lines.push_back (CellData<1>());
+ in >> subcelldata.boundary_lines.back().vertices[0]
+ >> subcelldata.boundary_lines.back().vertices[1];
+ subcelldata.boundary_lines.back().material_id = material_id;
+
+ // transform from ucd to
+ // consecutive numbering
+ for (unsigned int i=0; i<2; ++i)
+ if (vertex_indices.find (subcelldata.boundary_lines.back().vertices[i]) !=
+ vertex_indices.end())
+ // vertex with this index exists
+ subcelldata.boundary_lines.back().vertices[i]
+ = vertex_indices[subcelldata.boundary_lines.back().vertices[i]];
+ else
+ {
+ // no such vertex index
+ AssertThrow (false,
+ ExcInvalidVertexIndex(cell,
+ subcelldata.boundary_lines.back().vertices[i]));
+ subcelldata.boundary_lines.back().vertices[i] = -1;
+ };
+ }
+ else
+ if ((cell_type == 3) && (dim == 3))
+ // boundary info
+ {
+ subcelldata.boundary_quads.push_back (CellData<2>());
+ in >> subcelldata.boundary_quads.back().vertices[0]
+ >> subcelldata.boundary_quads.back().vertices[1]
+ >> subcelldata.boundary_quads.back().vertices[2]
+ >> subcelldata.boundary_quads.back().vertices[3];
+
+ subcelldata.boundary_quads.back().material_id = material_id;
+
+ // transform from gmsh to
+ // consecutive numbering
+ for (unsigned int i=0; i<4; ++i)
+ if (vertex_indices.find (subcelldata.boundary_quads.back().vertices[i]) !=
+ vertex_indices.end())
+ // vertex with this index exists
+ subcelldata.boundary_quads.back().vertices[i]
+ = vertex_indices[subcelldata.boundary_quads.back().vertices[i]];
+ else
+ {
+ // no such vertex index
+ Assert (false,
+ ExcInvalidVertexIndex(cell,
+ subcelldata.boundary_quads.back().vertices[i]));
+ subcelldata.boundary_quads.back().vertices[i] = -1;
+ };
+
+ }
+ else
+ // cannot read this
+ AssertThrow (false, ExcGmshUnsupportedGeometry(cell_type));
+ };
+
+
+ // check that no forbidden arrays are used
+ Assert (subcelldata.check_consistency(dim), ExcInternalError());
+
+ AssertThrow (in, ExcIO());
+
+ // do some clean-up on vertices...
+ delete_unused_vertices (vertices, cells, subcelldata);
+ // ... and cells
+ GridReordering<dim>::reorder_cells (cells);
+ tria->create_triangulation (vertices, cells, subcelldata);
+}
+
+
+
template <int dim>
void GridIn<dim>::skip_empty_lines (std::istream &in)
--- /dev/null
+//---------------------------- grid_in_msh_01.cc ---------------------------
+// $Id$
+// Version: $Name$
+//
+// Copyright (C) 2004 by the deal.II authors and Luca Heltai
+//
+// This file is subject to QPL and may not be distributed
+// without copyright and license information. Please refer
+// to the file deal.II/doc/license.html for the text and
+// further information on this license.
+//
+//---------------------------- grid_in_msh_01.cc ---------------------------
+
+
+// check whether we can read in with the gmsh format
+
+#include "../tests.h"
+#include <base/logstream.h>
+
+#include <grid/tria.h>
+#include <grid/tria_accessor.h>
+#include <grid/tria_iterator.h>
+#include <grid/grid_in.h>
+#include <grid/grid_out.h>
+
+#include <fstream>
+#include <cmath>
+
+
+template <int dim>
+void gmsh_grid (const char *name)
+{
+ Triangulation<dim> tria;
+ GridIn<dim> grid_in;
+ grid_in.attach_triangulation (tria);
+ std::ifstream input_file(name);
+ grid_in.read_msh(input_file);
+
+ deallog << " " << tria.n_active_cells() << " active cells" << std::endl;
+
+ int hash = 0;
+ int index = 0;
+ for (typename Triangulation<dim>::active_cell_iterator c=tria.begin_active();
+ c!=tria.end(); ++c, ++index)
+ for (unsigned int i=0; i<GeometryInfo<dim>::vertices_per_cell; ++i)
+ hash += (index * i * c->vertex_index(i)) % (tria.n_active_cells()+1);
+ deallog << " hash=" << hash << std::endl;
+}
+
+
+int main ()
+{
+ std::ofstream logfile("grid_in_msh_01.output");
+ deallog.attach(logfile);
+ deallog.depth_console(0);
+
+ try
+ {
+ gmsh_grid<2> ("grid_in_msh_01.2d.msh");
+ gmsh_grid<3> ("grid_in_msh_01.3d.msh");
+ }
+ catch (std::exception &exc)
+ {
+ std::cerr << std::endl << std::endl
+ << "----------------------------------------------------"
+ << std::endl;
+ std::cerr << "Exception on processing: " << std::endl
+ << exc.what() << std::endl
+ << "Aborting!" << std::endl
+ << "----------------------------------------------------"
+ << std::endl;
+ return 1;
+ }
+ catch (...)
+ {
+ std::cerr << std::endl << std::endl
+ << "----------------------------------------------------"
+ << std::endl;
+ std::cerr << "Unknown exception!" << std::endl
+ << "Aborting!" << std::endl
+ << "----------------------------------------------------"
+ << std::endl;
+ return 1;
+ };
+
+ return 0;
+}
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