[Nek5000-users] outpost parallel error

[nek5000-users at lists.mcs.anl.gov]

My userchk is structured this way:

...
        call pdnaupd(...)
...
c   here call to nek subroutines
c   for matrix-vector products
...
c    if outpost is called here, it works (serial and parallel)
c   call to Arpack postprocessing routine:
        call pdneupd(...,zz,...)
c   zz is a matrix storing the eigenvectors
c   call to arpack to nek format conversion, then
        call outpost(v1,v2,...)      ! this gets stuck in parallel

note that with 1 rank this code is working well. If I comment out the 
call to pdneupd, then it works in parallel, although it will not give 
any useful results.
Giuseppe


On 26/10/2014 14:36, nek5000-users at lists.mcs.anl.gov wrote:
> If you comment out the arpack call, does it work?
>
> ________________________________________
> From: nek5000-users-bounces at lists.mcs.anl.gov [nek5000-users-bounces at lists.mcs.anl.gov] on behalf of nek5000-users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov]
> Sent: Sunday, October 26, 2014 2:36 AM
> To: nek5000-users at lists.mcs.anl.gov
> Subject: Re: [Nek5000-users] outpost parallel error
>
> Hi Paul,
> thank for the answer.
> I tried both removing the .sch file before each run and using outpost
> instead of outpost2.
> Unfortunately none of these solved my problem.
> I have checked that outpost works in parallel before the Arpack pdneupd
> subroutine is called, so my guess is that the Arpack subroutine is
> modifying some flags forcing outpost to write the .sch file, only when
> called by 2 or more ranks.
> If somebody has further comments, please let me know.
> Best,
> Giuseppe
>
>
>
> On 25/10/2014 20:39, nek5000-users at lists.mcs.anl.gov wrote:
>> Hi Giuseppe,
>>
>> It looks as though you didn't remove the .sch file prior to the start
>> of your run?
>>
>> Nek is designed to not clobber the .sch file because they can contain
>> information that might have resulted from very long runs.  The onus
>> is thus on the user to manage those files.   The usual nek scripts move
>> those files to blah.sch1  if there is already a blah.sch file.
>>
>> It's possible, however, that something is messed up in the logic of outpost2().
>> That rarely gets exercised.   Is there a reason to not use outpost()?
>>
>> Paul
>>
>> ________________________________________
>> From:nek5000-users-bounces at lists.mcs.anl.gov  [nek5000-users-bounces at lists.mcs.anl.gov] on behalf ofnek5000-users at lists.mcs.anl.gov  [nek5000-users at lists.mcs.anl.gov]
>> Sent: Saturday, October 25, 2014 8:58 AM
>> To:nek5000-users at lists.mcs.anl.gov
>> Subject: [Nek5000-users] outpost parallel error
>>
>> Dear Neks,
>> in the usr file, after doing some manipulations on a known solution
>> (loaded from file with load_fld(...)), I save the computed values with a
>> call to outpost, like:
>>             call outpost2(u1(1,1,1,1),v1(1,1,1,1),
>>         &  w1(1,1,1,1),p1(1,1,1,1),
>>         &  p1(1,1,1,1),1,'arp')
>> While this is working correctly with 1 rank, in parallel it fails,
>> returning only the error message:
>> schfile:/.../myrun.sch
>> then it hangs for a while, with all processes consuming all the cpu time
>> until they are killed (so the .sch file is empty).
>> Does anybody have an idea on how this could be solved?
>> Best,
>> Giuseppe
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