[Dune] Trouble with matrix distribution

[Markus Blatt]

Hi,

On Wed, Oct 11, 2017 at 02:07:28PM +0200, Kumar, Paras wrote:
> I'am working on a problem which involves solving a linear equation
> system(arising out of an FE discretization) in parallel.
> 
> The matrix A is created in serial on the master process and is then to be
> redistributed on the slave processes. For this task I adopt the technique as
> described by here:
> 
> https://www.dr-blatt.de/blog/posts/creating_a_parallel_istl_matrix/
> 
> 
> The code compiles and run without any segmentation faults but the
> redistribution doesn't seem to happen. I get the following message when I
> run the code on 4 MPI processes.
> 
> PARMETIS ERROR: Poor initial vertex distribution. Processor 3 has no
> vertices assigned to it!
> PARMETIS ERROR: Poor initial vertex distribution. Processor 1 has no
> vertices assigned to it!
> PARMETIS ERROR: Poor initial vertex distribution. Processor 2 has no
> vertices assigned to it!
> 

I am sure that I never tested this ParMETIS as it is not free
software. The error message sounds like it needs at least one vertex
per process. Maybe you can check that in the documentation or as the
ParMETIS guys.

Have you tried using PT-Scotch? If the errro is there too, then I
might be able to help you.

Cheers,

Markus
-- 
Dr. Markus Blatt - HPC-Simulation-Software & Services http://www.dr-blatt.de
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