[dune-fem] parallel solver issue

[Andreas Dedner]

I found the mistake. No idea why that ever worked....
I'll test and commit later today
Andreas


On 11/04/15 12:56, Radcliffe, Alastair wrote:
> Hi fellow Dune-femers,
>
> I've come across an interesting issue with the non-convergence of the parallel solvers (istl or fem) for the (latest on the "stokes" branch) fem-howto example 04 when using Dirichlet boundary conditions on a dgf mesh i generated recently, see below.
>
> dune-fem version 1.4, and version 2.3 for the dune core modules
>
> Any feedback from someone who knows how the parallel solvers work would be gratefully received ...
>
> Thanks,
>
> Alastair
>
>
> ________________________________________
> From: Dedner, Andreas
> Sent: Friday, April 10, 2015 11:49 PM
> To: Radcliffe, Alastair
> Subject: Re: Fw: bug in alu or fem
>
> Hi Alastair.
> I can't figure out anything at the moment.
> You should perhaps report the bug to the dune-fem mailinglist with that
> dgf file.
> Andreas
>
>
> On 10/04/15 19:15, Radcliffe, Alastair wrote:
>> Hi,
>>
>> 'it' was a non-convergence of the solver, and the fem solvers didn't work either i think ... and of course, there are very few dune preconditioners that work in parallel to try ...
>>
>> the only way i've found to get it to 'solve' is to set the required residual to something e+3 or so ... then at least you can get paraview output to check it has "ranked" (ie: divided) the geometry up nicely ...
>>
>> i was hoping howto example 04 would do as a "minimal working example" for debugging ... but is it an alu or a dune-fem bug, so i can post it on the correct bug list ?
>>
>> Ta,
>>
>> Alastair
>>
>> ps: see you monday?, tuesday?, wednesday ? ...
>>
>> ________________________________________
>> From: Dedner, Andreas
>> Sent: Friday, April 10, 2015 4:18 PM
>> To: Radcliffe, Alastair
>> Subject: Re: Fw: bug in alu or fem
>>
>> Hi Alastair.
>> Yes I can conform it - whatever 'it' was in your case. You really have
>> to learn to write
>> meaningful and helpful error reports! In my case the program got stuck -
>> but is that the
>> same behaviour you saw? Also: what sort of tests did you do? For
>> example, did you see if
>> there is an endless loop in the solver (setting the verbosity flag to
>> 1)? I did do that and the
>> solver then printed "nan" for the residual. It starts off ok but then
>> goes bad. Did you test a
>> different solver, i.e., change the flag in Makefile.am to not use istl.
>> Anything else you tried/
>> Best
>> Andreas
>>
>>
>>
>> On 08/04/15 12:18, Radcliffe, Alastair wrote:
>>> mpiexec -np 2 main
>
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