[dune-pdelab] parallel pdelab for simple problem

[Peter Bastian]

Hello Eike,

YaspGrid can be used as nonoverlapping (overlap=0) and
overlapping grid (overlap>0). Since example4 is a cell-centered scheme
it only makes sense to use overlap>0. Then you have to use the
OVLP... backends, e.g. overlapping Schwarz with some subdomain solver.
As constraints use the P0ParallelConstraints. An example can be found
in the pdelab howto in src/convection-diffusion/transporttest.cc

Sorry, it is a bit confusing.

Best,

Peter



Am 27.09.2011 um 10:39 schrieb Eike Mueller:

> Dear dune-pdelab list,
> 
> I'm trying to adapt my serial code to run in parallel. Basically, I took  example 4 from the pdelab howto (I modified the local operator slightly) and use a 3d YaspGrid. I then modified my code according to section 3.3, i.e. I changed the constraints, use a parallel grid (again, YaspGrid with overlap 0) and changed to solver backend to one of the non-overlapping backends. However, the results are wrong, if I run with 8 cores then the solution is discontinuous across the faces that separate the eight domains. Also, alpha_skeleton of the local operator does not seem to get called for the faces between the domains. Is there an example of how to modify the local operator to make it parallel? Or do I have to choose a non-zero overlap in this case?
> 
> Thank you very much,
> 
> Eike
> 
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------------------------------------------------------------
Peter Bastian
Interdisziplinäres Zentrum für Wissenschaftliches Rechnen
Universität Heidelberg
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email: peter.bastian at iwr.uni-heidelberg.de
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