FEM_TO_MEDIT
Convert finite element mesh data from FEM to MEDIT format

FEM_TO_MEDIT is a C++ program which reads a set of FEM files defining the node coordinates, boundary nodes, and elements of a finite element mesh, and rewrites the data as a MEDIT mesh file.

The program can convert 2D meshes of triangles, or 3D meshes of tetrahedrons.

Usage:

fem_to_medit prefix

• prefix_nodes.txt is a file containing node coordinates;
• prefix_boundary_node_mask.txt is a file listing a "0" for each interior node and a "1" for each boundary node; (This file can be created by the triangulation_boundary_nodes or tet_mesh_boundary programs.)
• prefix_elements.txt is a file listing the nodes forming each element;
• prefix.mesh is the name of the MEDIT mesh file to be created.

Licensing:

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Languages:

FEM_TO_MEDIT is available in a C version and a C++ version and a FORTRAN77 version and a FORTRAN90 version and a MATLAB version.

Related Data and Programs:

FEM_TO_GMSH, a C++ program which reads FEM files definining a 1D, 2D or 3D mesh, namely a file of node coordinates and a file of elements defined by node indices, and creates a Gmsh mesh file.

FEM_TO_TRIANGLE, a C++ program which reads FEM files defining a 2D mesh of triangles, namely a file of node coordinates and a file of elements defined by node indices, and creates a corresponding pair of node and element files for use by Jonathan Shewchuk's triangle program.

FEM_TO_XML, a C++ program which reads FEM files defining a 1D, 2D or 3D mesh, namely a file of node coordinates and a file of elements defined by node indices, and creates a corresponding XML file for input to DOLFIN or FENICS.

FEM2D, a data directory which contains examples of 2D FEM files, text files that describe a 2D finite element geometry and associated nodal values;

FEM3D, a data directory which contains examples of 3D FEM files, three text files that describe a 3D finite element geometry and associated nodal values.

MEDIT, a data directory which contains examples of files which can be used by the MEDIT program to define a 2D or 3D mesh for use by the finite element method (FEM), using triangles, quadrilaterals, tetrahedrons or hexahedrons.

MEDIT, examples which illustrate the use of medit, an interactive graphics program developed to visualize numerical simulation results on unstructured meshes in two and three dimensions. Scalar, vector and tensor fields can be easily associated and displayed with meshes. The program is by Pascal Frey.

MEDIT_TO_FEM, a C++ program which reads a mesh file created by the MEDIT program and writes a corresponding pair of node and element files that correspond to the FEM format.

TRIANGLE_TO_MEDIT, a C++ program which reads the NODE and ELE files created by triangle() to describe a triangular mesh, and writes a corresponding MESH file for input to medit().

Reference:

1. Pascal Frey,
   MEDIT: An interactive mesh visualization software,
   Technical Report RT-0253,
   Institut National de Recherche en Informatique et en Automatique,
   03 December 2001.

Source Code:

• fem_to_medit.cpp, the source code.
• fem_to_medit.sh, BASH commands to compile the source code.

Examples and Tests:

ELL is a 2D L-shaped region, with a grid of 65 nodes and 96 elements of order 3 triangles.

• ell_nodes.txt
• ell_elements.txt
• ell_elements.png, an image of the triangulation.
• ell_boundary_node_mask.txt
• ell.mesh, the MESH file.

P01 is 3D FEM data for a rectangular channel of dimensions 3x1x1 physical units, using 584 nodes and 2568 tetrahedral elements.

• p01_nodes.txt, defines the FEM nodes.
• p01_elements.txt, defines the FEM elements.
• p01.png, an image of the mesh.
• p01_boundary_node_mask.txt
• p01.mesh, the MESH file.

List of Routines:

• MAIN is the main program for FEM_TO_MEDIT.
• CH_CAP capitalizes a single character.
• CH_EQI is true if two characters are equal, disregarding case.
• CH_TO_DIGIT returns the integer value of a base 10 digit.
• FILE_COLUMN_COUNT counts the columns in the first line of a file.
• FILE_ROW_COUNT counts the number of row records in a file.
• I4MAT_DATA_READ reads data from an I4MAT file.
• I4MAT_HEADER_READ reads the header from an I4MAT file.
• MESH_WRITE writes mesh data to a MESH file.
• R8MAT_DATA_READ reads the data from an R8MAT file.
• R8MAT_HEADER_READ reads the header from an R8MAT file.
• S_LEN_TRIM returns the length of a string to the last nonblank.
• S_TO_I4 reads an I4 from a string.
• S_TO_I4VEC reads an I4VEC from a string.
• S_TO_R8 reads an R8 from a string.
• S_TO_R8VEC reads an R8VEC from a string.
• S_WORD_COUNT counts the number of "words" in a string.
• TIMESTAMP prints the current YMDHMS date as a time stamp.

You can go up one level to the C++ source codes.