### Highlights from Finite Element Toolbox 2.1

4.05556
4.1 | 20 ratings Rate this file 25 Downloads (last 30 days) File Size: 132 KB File ID: #2808 Version: 1.0

# Finite Element Toolbox 2.1

### Rasmus Anthin (view profile)

03 Dec 2002 (Updated )

Piecewise linear Galerkin method with piecewise constant coeffs for static PDE probelms.

File Information
Description

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
I've discovered that the piecewise coefficients method I'm using is wrong. To get correct results use constant coefficients. This will be corrected in the next version. This will make the release for the next version a bit more delayed than expected. I'm also writing a paper on how FEM works that will be included in the toolbox (as a tutorial).

Version 3.0 will contain:
* 3D FEM
* improved function documentations
* introduction to applied linear Galerkin (document)
* correction of the piecewise constant coefficients
* correction on how to enter Robin condition in the 1D case
* improved syntax

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

This is a toolbox for computing ODEs or PDEs in BVPs using FEM in 1D, 2D (and 3D, yet to come).

* FEM1
this is the main routine for solving ODE BVPs using any combination of Dirichlet, Neumann or Robin conditions.

* GENMAT1
called by FEM1 and is the core of the program. It generates the matrices used for solving the linear equation system for the ODE. Uses alytical results of the integration of basis functions (for sake of efficiency).

* REFINE1
with this routine you can refine the mesh over certain critical grid points. The the gridpoints will become nonuniformly linearly spaced.

* TEST1
this is a test for the 1D case of FEM. Look through this example carefully in order to fully understand how FEM1 works.

* PLOTGRID2
plot mesh/triangulation in 2D and put a number in each corresponding element (triangle).

generates quadratically spaced vectors. That is, the spaces are linearly decreasing/increasing.

* FEM2
this is the main routine for solving PDE BVPs using any combination of Dirichlet, Neumann or Robin conditions.

* GENMAT2
called by FEM2 and is the core of the program. It generates the matrices used for solving the linear equation system for the PDE.

* TEST2
test for the 2D case of FEM. Test this for better learning how to use FEM2 and other utilities.

Both FEM1 and FEM2 uses the sparse class in order to become more efficient (since the matrices generated are in general tridiagonal).

These routines may be useful for solving electrostatic problems with strange geometries and with spatially changing dielectric constants (or similar).
Of course the elliptical problem is universal and can be used for a lot of other applications such as the classical heat equation, etc...

Unfortunately, the FEM solvers does not support parabolic nor hyperbolic problems "yet".

the FEM1 and FEM2 routines should be fairly user friendly, and not much knowledge about finite elements ought to be required to operate them.

Remark: in the FEM1 routine you have to enter the neumann/(robin)-condition as

U'(a)+gamma*U(a)=R

rather than

alpha*U'(a)+gamma*U(a)=R

and I will correct this minor inconsistency for future versions.

Have fun!

More toolboxes and assorted m-files can be found at:
http://www.etek.chalmers.se/~e8rasmus/eng/matlab_programs.html

MATLAB release MATLAB 5.2 (R10)
26 Apr 2010 Methodist Hospital System Tan

### Methodist Hospital System Tan (view profile)

by the way, i can not reach you via the email you offered.

Comment only
26 Apr 2010 Methodist Hospital System Tan

### Methodist Hospital System Tan (view profile)

18 Sep 2009 Pier-Yves

### Pier-Yves (view profile)

When do you expect the 3.0 version to be available ?

Comment only
25 Sep 2008 liviu b

...

08 Jul 2008 Didit Nugroho
14 Jun 2008 alaa taha

thank u

????? ???? ????

Comment only
13 Apr 2008 hamlet hamlet

probleme de stabilité des plaques la matrice
de geometrie et element finis par matleb

Comment only
06 Mar 2008 OSCAR NARDUZZU
01 Mar 2008 HICHEM HERMI

ASSEMBLER DES TRIANGLES 2D PAR L4EQUATION ELLIPTIQUES ET PAR LE LANGUAGE MATLAB

Comment only
30 Jan 2008 yuga gautama

GOOD

28 Jan 2008 yuga gautama

good

28 Jan 2008 yuga gautama
21 Jan 2008 arash shabani

tanks for useful helps.

Comment only
07 May 2007 david Zeitoun
18 Apr 2007 joao gouveia
17 Oct 2006 kyun wo

none of the links (chalmers.se) you provided are working.

18 Mar 2006 osmar monteagudo
09 Feb 2006 phuong nguyen
05 Sep 2005 Rasmus Anthin

Ok... this project has been on ice for some time and it is uncertain when I can pick it up again. Perhaps within a year or two. If you are interested in the theory behind Galerkin finite elements, you can read my article about it:
http://www.etek.chalmers.se/~e8rasmus/eng/facts/galerkin(1).pdf
it is not yet completed though. The article will be included in the next version of this toolbox.
/the author.

Comment only
04 Aug 2005 Hieu Vu Duc

Good!
Thank!

good

Comment only
12 Apr 2005 Johnny C.

Great package, works well and runs fast. More comments in the source code would help students taking a FEM course understand how the included functions work. This, of course, isn't needed for just using the package.

14 Mar 2005 Hossein Kazemi

Thanks

Comment only
18 Dec 2004 abbassi ammar
14 May 2004 lalu PP
23 Mar 2004 (author) Rasmus Anthin

It'll be fixed for next version. There might be some incompability with the mat-files somehow, that I do not understand :). Another explanation could be that it have been corrupted in the packing or unpacking process of the toolbox. Seems that mat-files are sensitive to compression.

Comment only
05 Mar 2004 Syed Ali

Ex1 does not work

Comment only
24 Aug 2003 Zhang Shaozhi

good

03 Sep 2003

Only changed the packing format from tar.gz to zip since many people seems to have problems with corrupted mat-files. The tar.gzipped file can still be found on my homepage.

23 Oct 2003

Updated information/description.

17 Nov 2003

Updated information/description.