Hi, I always liked idea of a *simple* parallel FEM code in Petsc, which shows most of tricks used in various programs, like parallel assembly of elements and imposing Dirichlet BCs in a proper way. I think this can eliminate many of "How should I do that" questions from newbies like me. I think this is almost a series of copy-paste's for you. With a little documentation this would be a great help.
Best regards, Farshid Mossaiby --- On Tue, 8/12/08, Barry Smith <bsmith at mcs.anl.gov> wrote: > From: Barry Smith <bsmith at mcs.anl.gov> > Subject: Re: petsc and x-fem > To: petsc-dev at mcs.anl.gov > Cc: "Techas" <techas at gmail.com> > Date: Tuesday, August 12, 2008, 7:48 PM > There is also one other example that is a lower level then > sieve > where the application more directly manages the mesh data > structure. > This is example is src/snes/examples/tutorials/ex10d. It is > not really > a complete example but gives the outline of how one can > write > such a code. > > Barry > > On Aug 12, 2008, at 6:28 AM, Matthew Knepley wrote: > > > 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