[petsc-users] [petsc-maint] petsc ksp solver hangs

[Stefano Zampini]

In my experience, an hanging execution may results from seterrq being
called with the wrong communicator. Anyway, it would be useful to get the
output of -log_trace .

Also, does it hang when -pc_type none is specified?

Il Sab 28 Set 2019, 16:22 Zhang, Junchao via petsc-users <
petsc-users at mcs.anl.gov> ha scritto:

> Does it hang with  2 or 4 processes? Which PETSc version do you use (using
> the latest is easier for us to debug)?  Did you configure PETSc with
> --with-debugging=yes COPTFLAGS="-O0 -g"  CXXOPTFLAGS="-O0 -g"
> After attaching gdb to one process, you can use bt  to see its stack trace.
>
> --Junchao Zhang
>
>
> On Sat, Sep 28, 2019 at 5:33 AM Michael Wick <michael.wick.1980 at gmail.com>
> wrote:
>
>> I attached a debugger to my run. The code just hangs without throwing an
>> error message, interestingly. I uses 72 processors. I turned on the ksp
>> monitor. And I can see it hangs either at the beginning or the end of KSP
>> iteration. I also uses valgrind to debug my code on my local machine, which
>> does not detect any issue. I uses fgmres + fieldsplit, which is really a
>> standard option.
>>
>> Do you have any suggestions to do?
>>
>> On Fri, Sep 27, 2019 at 8:17 PM Zhang, Junchao <jczhang at mcs.anl.gov>
>> wrote:
>>
>>> How many MPI ranks did you use? If it is done on your desktop, you can
>>> just attach a debugger to a MPI process to see what is going on.
>>>
>>> --Junchao Zhang
>>>
>>>
>>> On Fri, Sep 27, 2019 at 4:24 PM Michael Wick via petsc-maint <
>>> petsc-maint at mcs.anl.gov> wrote:
>>>
>>>> Hi PETSc:
>>>>
>>>> I have been experiencing a code stagnation at certain KSP iterations.
>>>> This happens rather randomly, which means the code may stop at the middle
>>>> of a KSP solve and hangs there.
>>>>
>>>> I have used valgrind and detect nothing. I just wonder if you have any
>>>> suggestions.
>>>>
>>>> Thanks!!!
>>>> M
>>>>
>>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20190928/5f1ea2b1/attachment-0001.html>