petsc and x-fem

[Matthew Knepley]

On Mon, Aug 4, 2008 at 6:49 AM, Techas <techas at gmail.com> wrote:

> Hi Matthew,
>
> I'm Sergio (X-FEM), we meet some weeks ago in Davis.
> I'm playing a little bit with petsc to evaluate how much work will
> take me mount my x-fem code on petsc.


Sorry I am just replying now. I returned from Norway yesterday.


>
> My first question is: can you tell me a good example of the assembly
> of a global finite element matrix (distributed in n procs) based on a
> distributed mesh?


The answers is in two parts. If you have a structured grid, then the DA
construct can do everything and is very simple. You just call
MatSetValuesStencil()
as in KSP ex2.

If you have an unstructured grid, we have new functionality (only in the
development version) in a Mesh object. This will be in the upcoming release,
but you can see it now in src/dm/mesh/sieve/problems/Bratu.hh. The function
to examine is Rhs_Unstructured() which forms the residual for this equation
on an unstructured mesh. Unfortunately, this is new and has little
documentation.
Before the release, I will write some, but until then you will have to ask
me
questions if you want to try it out.

  Thanks,

     Matt


>
> If you want me to write to the petsc list just tell me.
>
> thank you!
> Sergio.
>
> --
> Sergio Zlotnik, PhD
> Group of Dynamics of the Lithosphere -GDL-
> Department of Geophysics & Tectonics
> Institute of Earth Sciences - CSIC
> Sole Sabaris s/n
> Barcelona 08028 - SPAIN
>
> Tel: +34 93 409 54 10
> Fax: +34 93 411 00 12
> email: szlotnik at ija.csic.es
>
> Web page http://www.ija.csic.es/gt/sergioz/
>



-- 
What most experimenters take for granted before they begin their experiments
is infinitely more interesting than any results to which their experiments
lead.
-- Norbert Wiener
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-dev/attachments/20080812/ea4e1a33/attachment.html>