Hi Etienne,

as Christoph points out, the effect you see is that a problem occurs on one 
process and other processes are waiting. I don't expect the linear solver to 
cause the deadlock, since quite some care is taken there to avoid exactly that. 
I recommend that you recompile with debug options. This might give you a more 
meaningful error message. If not, you have to enter the joy of parallel 
debugging.

It is very unusual that the AMG is so much slower. As Christoph says, solving 
directly on the coarsest level can be important. You can try to make a minimal 
example on top of a standard Dumux model so that we can take a look.

Kind regards
Bernd


 Tue, 13 Dec 2016 16:09:25 +0100
 Christoph Grüninger    <[email protected]> wrote:
>Hi Etienne,
>as I did never parallel runs with DuMuX myself, I can only guess.
>
>My guess is, that your linear solver does not converge and you don't see
>the error because some process is waiting for the result from a process
>that terminated due to the failed convergence. So it will never
>show the error or terminate.
>
>> For the AMG solver, are there some additional parameters to give?
>
>Do you use SuperLU or UMFPack or an iterative method after you
>preconditioned with AMG? Markus Blatt often advises to use the direct
>methods as the iterative ones are prone to breakdown. Might be worth a try…
>
>Bye
>Christoph
>
>-- 
>AddressSanitizer is not expected to produce false positives.
>If you see one, look again; most likely it is a true positive!
>[http://clang.llvm.org/docs/AddressSanitizer.html]
>

_______________________________________________________________

Bernd Flemisch                         phone: +49 711 685 69162
IWS, Universitaet Stuttgart              fax: +49 711 685 67020
Pfaffenwaldring 61            email: [email protected]
D-70569 Stuttgart            url: www.hydrosys.uni-stuttgart.de
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