FEM_IO
Read or Write a Finite Element Model

FEM_IO is a library of MATLAB routines for reading or writing the data that defines a finite element model.

The finite element model is assumed to include three items:

• Node coordinates;
• Elements defined by a sequence of node indices;
• Node data;

Related Data and Programs:

FEM is a data directory which contains a description of the data files that can be used to describe a finite element model.

FEM_50 is a MATLAB finite element program in just 50 lines of code.

FEM_50_HEAT is a modified version of FEM_50 suitable for solving the heat equation.

FEM_BASIS_T3_DISPLAY is a MATLAB program which displays a basis function associated with a linear triangle ("T3") mesh.

FEM_BASIS_T6_DISPLAY is a MATLAB program which reads a quadratic triangle mesh and displays any associated basis function.

FEM_IO is also available in a C++ version and a FORTRAN90 version.

FEM_SAMPLE is a MATLAB library of routines for evaluating a finite element function defined on an order 3 or order 6 triangulation.

FEM_TO_TEC is a MATLAB program that can convert an FEM model into a TEC graphics file.

FEM1D, is a MATLAB program which applies the finite element method, with piecewise linear basis functions, to a linear two point boundary value problem;

FEM1D_ADAPTIVE is a MATLAB program that applies the finite element method to a linear two point boundary value problem in a 1D region, using adaptive refinement to improve the solution.

FEM1D_NONLINEAR is a MATLAB program that applies the finite element method to a nonlinear two point boundary value problem in a 1D region.

FEM1D_PMETHOD is a MATLAB program that applies the p-method version of the finite element method to a linear two point boundary value problem in a 1D region.

FEM2D_HEAT is a MATLAB program that solves the time dependent heat equation in the unit square.

FEM2D_POISSON is a MATLAB program for solving Poisson's equation on a square, using the finite element method.

FEMPACK is a MATLAB library of routines for finite element calculations.

FREE_FEM_HEAT is a MATLAB program that solves the time dependent heat equation in an arbitrary triangulated 2D region.

FREE_FEM_POISSON is a MATLAB program for solving Poisson's equation on a triangulated region, using the finite element method.

FREE_FEM_STOKES is a MATLAB program for solving the Stokes equations on a triangulated region, using the finite element method.

HOT_PIPE is a sample problem that can be run with FEM_50_HEAT.

HOT_POINT is a sample problem that can be run with FEM_50_HEAT.

PLTMG_SINGLE is a FORTRAN77 library of routines for solving elliptic partial differential equations using the finite element method with piecewise linear triangles and the multigrid approach.

TABLE is a file format which is used for the input and output files used by FEM_IO.

TABLE_IO is a MATLAB library of routines for reading and writing TABLE files.

Reference:

1. Hans Rudolf Schwarz,
   Methode der Finiten Elemente,
   Teubner Studienbuecher, 1980,
   ISBN: 3-519-02349-0.
2. Gilbert Strang, George Fix,
   An Analysis of the Finite Element Method,
   Cambridge, 1973,
   ISBN: 096140888X,
   LC: TA335.S77.
3. Olgierd Zienkiewicz,
   The Finite Element Method,
   Sixth Edition,
   Butterworth-Heinemann, 2005,
   ISBN: 0750663200.
4. Daniel Zwillinger, editor,
   CRC Standard Mathematical Tables and Formulae,
   30th Edition,
   CRC Press, 1996,
   ISBN: 0-8493-2479-3.

Tar File:

A GZIP'ed TAR file of the contents of this directory is available. This is only done as a convenience for users who want ALL the files, and don't want to download them individually. This is not a convenience for me, so don't be surprised if the tar file is somewhat out of date.

• fem_io_m_src.tar.csh the commands used to create the GZIP'ed TAR file.
• fem_io_m_src.tar.gz the GZIP'ed TAR file.

Source Code:

• fem_read.m reads the node coordinate, element and node data files defining a finite element model.
• fem_write.m writes the node coordinate, element and node data files defining a finite element model.
• file_column_count.m counts the number of columns in a file.
• file_name_specification.m determines the names of the input files.
• file_row_count.m counts the number of rows in a file.
• i4mat_transpose_print.m prints an I4MAT, transposed.
• i4mat_transpose_print_some.m prints some of an I4MAT, transposed.
• itable_data_read.m reads a table from an integer table file.
• itable_data_write.m writes a table to an integer table file.
• itable_header_read.m reads the header from an integer table file.
• itable_header_write.m writes the header of an integer table file.
• r8_epsilon.m returns the machine roundoff for an R8.
• r8mat_transpose_print.m prints an R8MAT, transposed.
• r8mat_transpose_print_some.m prints some of an R8MAT, transposed.
• r8table_data_read.m reads data from an R8TABLE file.
• r8table_data_write.m writes data to an R8TABLE file.
• r8table_header_read.m reads the header from an R8TABLE file.
• r8table_header_write.m writes a header to an R8TABLE file.
• s_len_trim.m returns the length of a string to the last nonblank.
• s_word_count.m counts the number of words in a line.
• timestamp.m prints the current YMDHMS date as a timestamp.
• timestring.m stores the current YMDHMS date in a string.

Examples and Tests:

FEM_IO_TEST is a test program which tests the routines that read and write finite element data.

• fem_io_test.m runs all the tests.
• fem_io_test01.m tests FEM_READ by reading the ELL data.
• fem_io_test02.m tests FEM_WRITE by writing the TINY data.
• fem_io_test.out, the output from the tests.

ELL is an example of a 2D finite element model in which a scalar value is stored. This data was computed by the FREE_FEM_POISSON program and is read by FEM_READ.

• ell_node_coord.txt
• ell_element.txt
• ell_node_data.txt

TINY is a "tiny" example of a 2D finite element model in which a vector value is stored. This data was written by the FEM_WRITE routine.

• tiny_coord.txt
• tiny_element.txt
• tiny_node_data.txt

You can go up one level to the MATLAB source codes.