FEM_TO_XML
Convert Mesh Data from FEM to DOLFIN XML Format

FEM_TO_XML is a C++ program which reads FEM files of node coordinates and element connectivity, which define a mesh of a 1D, 2D, or 3D region and creates a corresponding DOLFIN XML file.

These mesh files can be used as input to DOLFIN or FENICS.

Usage:

fem_to_xml prefix

where prefix is the common filename prefix:

'prefix'_nodes.txt contains the node coordinates,
'prefix'_elements.txt contains the element definitions.
'prefix'.xml will contain the DOLFIN XML mesh file.

Licensing:

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

Languages:

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

Related Data and Programs:

DOLFIN-CONVERT, a Python program which can convert mesh file from Gmsh, MEDIT, METIS or SCOTCH format to an XML format suitable for use by DOLFIN or FENICS, by Anders Logg.

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_MEDIT, a C++ program which reads a pair of FEM files defining node coordinates and elements, and creates a corresponding MEDIT 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.

FENICS, programs which illustrate the use of a collection of free software with an extensive list of features for automated, efficient solution of differential equations.

MITCHELL_FENICS, examples which illustrate the implementation of the Mitchell 2D elliptic partial differential equation (PDE) test problems using FENICS.

TET_MESH, a C++ library which carries out various operations on tetrahedral meshes.

TRIANGULATION, a C++ library which performs various operations on order 3 (linear) or order 6 (quadratic) triangulations.

XML, a data directory which contains examples of XML files, a standard, general datafile format.

XML_TO_FEM, a Python program which reads an XML file created by FENICS or DOLFIN, describing a mesh in 1D, 2D, or 3D, and creates corresponding FEM files, namely, a file of node coordinates, and a file of element connectivities.

Reference:

Anders Logg, Kent-Andre Mardal, Garth Wells,
Automated Solution of Differential Equations by the Finite Element Method: The FEniCS Book,
Lecture Notes in Computational Science and Engineering,
Springer, 2011,
ISBN13: 978-3642230981,
LC:

Source Code:

fem_to_xml.cpp, the source code.
fem_to_xml.sh, commands to compile the source code.

Examples and Tests:

BATTERY is a rectangular region which was subdivided into 7 faces which were meshed together by MESHFACES.

battery_nodes.txt, the node coordinates.
battery_elements.txt, the elements.
battery.png, a PNG image of the triangulation.
battery.xml, the corresponding DOLFIN XML mesh file.

CHANNEL/b> is a 3D region, [0,3]x[0,1]x[0,1] [-1,+1], containing 63 nodes and 144 elements.

channel_nodes.txt, the node coordinates.

channel_elements.txt, the elements.

channel.xml, the corresponding DOLFIN XML mesh file.

CHEBY9 is a 1D interval, [-1,+1], containing 9 nodes and 8 elements.

cheby9_nodes.txt, the node coordinates.

cheby9_elements.txt, the elements.

cheby9.xml, the corresponding DOLFIN XML mesh file.

CIRCLE is a 2D circular region which was meshed by MESH2D.

circle_nodes.txt, the node coordinates.

circle_elements.txt, the elements.

circle.png, a PNG image of the triangulation.

circle.xml, the corresponding DOLFIN XML mesh file.

RECTANGLE is a rectangular region which has been divided into 3 rows and 4 columns of squares, each then split into two 3-node triangles.

rectangle_nodes.txt, the node coordinates.

rectangle_elements.txt, the elements.

rectangle.png, a PNG image of the triangulation, created by TRIANGULATION_PLOT.

rectangle.xml, the corresponding DOLFIN XML mesh file.

List of Routines:

MAIN is the main program for FEM_TO_XML.

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.

I4_MAX returns the maximum of two I4's.

I4_MIN returns the minimum of two I4's.

I4MAT_DATA_READ reads data from an I4MAT file.

I4MAT_HEADER_READ reads the header from an I4MAT file.

I4MAT_TRANSPOSE_PRINT prints an I4MAT, transposed.

I4MAT_TRANSPOSE_PRINT_SOME prints some of an I4MAT, transposed.

MESH_BASE_ZERO ensures that the element definition is zero-based.

R8MAT_DATA_READ reads the data from an R8MAT file.

R8MAT_HEADER_READ reads the header from an R8MAT file.

R8MAT_TRANSPOSE_PRINT prints an R8MAT, transposed.

R8MAT_TRANSPOSE_PRINT_SOME prints some of an R8MAT, transposed.

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.

XML_WRITE writes the triangulation data as a DOLFIN XML mesh file.

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

Last revised on 06 October 2014.

FEM_TO_XML Convert Mesh Data from FEM to DOLFIN XML Format