[petsc-users] Irritating behavior of MUMPS with PETSc

[Matthew Knepley]

On Wed, Jun 25, 2014 at 7:09 AM, Gunnar Jansen <jansen.gunnar at gmail.com>
wrote:

> You are right about the queuing system. The job is submitted with a PBS
> script specifying the number of nodes/processors. On the cluster petsc is
> configured in a module environment which sets the appropriate flags for
> compilers/rules etc.
>
> The same exact job script on the same exact nodes with a standard krylov
> method does not give any trouble but executes nicely on all processors (and
> also give the correct result).
>
> Therefore my suspicion is a missing flag in the mumps interface. Is this
> maybe rather a topic for the mumps-dev team?
>

I doubt this. The whole point of MPI is to shield code from these details.

Can you first try this system with SuperLU_dist?

  Thanks,

     MAtt


> Best, Gunnar
>
>
>
> 2014-06-25 15:52 GMT+02:00 Dave May <dave.mayhem23 at gmail.com>:
>
> This sounds weird.
>>
>> The launch line you provided doesn't include any information regarding
>> how many processors (nodes/nodes per core to use). I presume you are using
>> a queuing system. My guess is that there could be an issue with either (i)
>> your job script, (ii) the configuration of the job scheduler on the
>> machine, or (iii) the mpi installation on the machine.
>>
>> Have you been able to successfully run other petsc (or any mpi) codes
>> with the same launch options (2 nodes, 3 procs per node)?
>>
>> Cheers.
>>   Dave
>>
>>
>>
>>
>> On 25 June 2014 15:44, Gunnar Jansen <jansen.gunnar at gmail.com> wrote:
>>
>>> Hi,
>>>
>>> i try to solve a problem in parallel with MUMPS as the direct solver. As
>>> long as I run the program on only 1 node with 6 processors everything works
>>> fine! But using 2 nodes with 3 processors each gets mumps stuck in the
>>> factorization.
>>>
>>> For the purpose of testing I run the ex2.c on a resolution of 100x100
>>> (which is of course way to small for a direct solver in parallel).
>>>
>>> The code is run with :
>>> mpirun ./ex2 -on_error_abort -pc_type lu -pc_factor_mat_solver_package
>>> mumps -ksp_type preonly -log_summary -options_left -m 100 -n 100
>>> -mat_mumps_icntl_4 3
>>>
>>> The petsc-configuration I used is:
>>> --prefix=/opt/Petsc/3.4.4.extended --with-mpi=yes
>>> --with-mpi-dir=/opt/Openmpi/1.9a/ --with-debugging=no --download-mumps
>>>  --download-scalapack --download-parmetis --download-metis
>>>
>>> Is this common behavior? Or is there an error in the petsc configuration
>>> I am using here?
>>>
>>> Best,
>>> Gunnar
>>>
>>
>>
>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
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