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Finite Element Toolbox 2.1

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Finite Element Toolbox 2.1

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03 Dec 2002 (Updated )

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

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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).

* QUADSPACE
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)
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Comments and Ratings (31)
26 Apr 2010 Methodist Hospital System Tan

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

26 Apr 2010 Methodist Hospital System Tan  
18 Sep 2009 Pier-Yves

When do you expect the 3.0 version to be available ?

25 Sep 2008 liviu b

...

08 Jul 2008 Didit Nugroho  
14 Jun 2008 alaa taha

thank u

10 Jun 2008 HANAN BAGHDADY

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

13 Apr 2008 hamlet hamlet

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

06 Mar 2008 OSCAR NARDUZZU  
01 Mar 2008 HICHEM HERMI

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

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.

22 Dec 2007 roozbeh Behzadi

Hi,thanks for your help

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.

04 Aug 2005 Hieu Vu Duc

Good!
Thank!

27 Apr 2005 adi sayoga

good

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

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.

05 Mar 2004 Syed Ali

Ex1 does not work
load ex1 gives error.

24 Aug 2003 Zhang Shaozhi

good

16 May 2003 javad Eashraghi  
Updates
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.

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