[dune-pdelab] Reg: terminal freezes at vtk output

[Steffen Müthing]

Hi Shubhangi,

that version contains the fix that makes sure you always get an error message. Does your
program also hang in sequential runs? My next step would probably be to run a debug build
and see if that hangs as well. If it does, I'd attach a debugger to the hanging process to see
where exactly the problem is happening.

Steffen

> Am 10.10.2018 um 13:07 schrieb Shubhangi Gupta <sgupta at geomar.de>:
> 
> Hi Stefan,
> 
> I am running version 2.5. The program just silently freezes. There are no error messages.
> 
> 
> On 10.10.2018 13:05, Steffen Müthing wrote:
>> HI Shubhangi,
>> 
>>> Am 09.10.2018 um 21:35 schrieb Shubhangi Gupta <sgupta at geomar.de>:
>>> 
>>> Hi Steffen,
>>> 
>>> Thanks a lot for your reply! This is happening on my laptop, and also on the cluster... hmmm... I am not sure what to do next... DO you maybe have any suggestions?
>> what version of Dune are you running? Errors before the start of VTK output are often related to missing
>> directories for the files, and there were some bug fixes in recent Dune versions. Do you get any kind
>> of error message, or does the program just silently freeze?
>> 
>> Steffen
>> 
>>> Thanks again, and best wishes, Shubhangi
>>> 
>>> 
>>> On 09.10.2018 21:02, Steffen Müthing wrote:
>>>> Hi Shubhangi,
>>>> 
>>>>> Am 09.10.2018 um 16:32 schrieb Shubhangi Gupta <sgupta at geomar.de>:
>>>>> 
>>>>> Dear all,
>>>>> 
>>>>> I am currently experiencing a really strange problem during the execution of my dune program... When I run the problem in parallel, the program execution freezes in the terminal just before writing the vtk output file... the freeze occurs randomly, sometimes right before the first output, but sometimes after 5, 20, or even 500 outputs, even though I don't change anything about my problem setting! I am really puzzled, and I'll be very thankful for suggestions for solving/debugging this!
>>>> that really sounds strange. The one explanation I can think of is a race condition. Are you running this on a cluster with a network file system?
>>>> In that case, there might be an issue where one rank tries to write to a per-timestep subdirectory before the creation of that subdirectory has
>>>> been flushed from rank 0 to the file server and the other compute nodes, but that’s just guessing right now (but that might explain the freeze if
>>>> the program crash is not properly propagated by your MPI / batch system).
>>>> 
>>>> Steffen
>>>> 
>>>>> Thanks in advance, and best wishes, Shubhangi
>>>>> 
>>>>> PS: So far, this problem occurs only in parallel. I write vtk output as follows:
>>>>>         int subsampling = 0;
>>>>>         typedef Dune::SubsamplingVTKWriter<GV> VTKWRITER;
>>>>>         VTKWRITER vtkwriter(gv,subsampling,(int)0);
>>>>>         typedef Dune::VTKSequenceWriter<GV> VTKSEQUENCEWRITER;
>>>>>         VTKSEQUENCEWRITER vtkSequenceWriter(    std::make_shared<
>>>>> 	VTKWRITER (vtkwriter), fileName, pathName,""    );
>>>>>         .....
>>>>>         .....
>>>>>         vtkSequenceWriter.write(time,Dune::VTK::appendedraw);
>>>>> 
>>>>> 
>>>>> --
>>>>> Dr. Shubhangi Gupta
>>>>> Marine Geosystems
>>>>> GEOMAR Helmholtz Center for Ocean Research
>>>>> Wischhofstraße 1-3,
>>>>> D-24148 Kiel
>>>>> 
>>>>> Room: 12-206
>>>>> Phone: +49 431 600-1402
>>>>> Email:
>>>>> sgupta at geomar.de
>>>>> 
>>>>> 
>>>>> 
>>>>> _______________________________________________
>>>>> dune-pdelab mailing list
>>>>> dune-pdelab at lists.dune-project.org
>>>>> https://lists.dune-project.org/mailman/listinfo/dune-pdelab
>>> --
>>> Dr. Shubhangi Gupta
>>> Marine Geosystems
>>> GEOMAR Helmholtz Center for Ocean Research
>>> Wischhofstraße 1-3,
>>> D-24148 Kiel
>>> 
>>> Room: 12-206
>>> Phone: +49 431 600-1402
>>> Email: sgupta at geomar.de
>>> 
>>> 
> 
> --
> Dr. Shubhangi Gupta
> Marine Geosystems
> GEOMAR Helmholtz Center for Ocean Research
> Wischhofstraße 1-3,
> D-24148 Kiel
> 
> Room: 12-206
> Phone: +49 431 600-1402
> Email: sgupta at geomar.de
> 
> 

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