[petsc-users] Automatically re-solving after MUMPS error

[Matt Landreman]

PETSc developers,

I tried implementing a system for automatically increasing MUMPS ICNTL(14),
along the lines described in this recent thread. If SNESSolve returns ierr
.ne. 0 due to MUMPS error -9, I call SNESDestroy, re-initialize SNES, call
MatMumpsSetIcntl with a larger value of ICNTL(14), call SNESSolve again,
and repeat as needed. The procedure works, but the peak memory required (as
measured by the HPC system) is 50%-100% higher if the MUMPS solve has to be
repeated compared to when MUMPS works on the 1st try (by starting with a
large ICNTL(14)), even though SNESDestroy is called in between the
attempts. Are there some PETSc or MUMPS structures which would not be
deallocated immediately by SNESDestroy?  If so, how do I deallocate them?

Thanks,
Matt Landreman


On Tue, Sep 15, 2015 at 7:47 AM, David Knezevic <david.knezevic at akselos.com>
wrote:

> On Tue, Sep 15, 2015 at 7:29 PM, Matthew Knepley <knepley at gmail.com>
> wrote:
>
>> On Tue, Sep 15, 2015 at 4:30 AM, David Knezevic <
>> david.knezevic at akselos.com> wrote:
>>
>>> In some cases, I get MUMPS error -9, i.e.:
>>> [2]PETSC ERROR: Error reported by MUMPS in numerical factorization
>>> phase: INFO(1)=-9, INFO(2)=98927
>>>
>>> This is easily fixed by re-running the executable with
>>> -mat_mumps_icntl_14 on the commandline.
>>>
>>> However, I would like to update my code in order to do this
>>> automatically, i.e. detect the -9 error and re-run with the appropriate
>>> option. Is there a recommended way to do this? It seems to me that I could
>>> do this with a PETSc error handler (e.g. PetscPushErrorHandler) in order to
>>> call a function that sets the appropriate option and solves again, is that
>>> right? Are there any examples that illustrate this type of thing?
>>>
>>
>> I would not use the error handler. I would just check the ierr return
>> code from the solver. I think you need the
>> INFO output, for which you can use MatMumpsGetInfo().
>>
>
>
> OK, that sounds good (and much simpler than what I had in mind), thanks
> for the help!
>
> David
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20150930/8e85f7e1/attachment.html>