[petsc-users] MUMPS error

[Matthew Knepley]

On Sun, May 17, 2015 at 1:38 AM, venkatesh g <venkateshgk.j at gmail.com>
wrote:

> Hi, Thanks for the information. I now increased the workspace by adding
> '-mat_mumps_icntl_14 100'
>
> It works. However, the problem is, if I submit in 1 core I get the answer
> in 200 secs, but with 4 cores and '-mat_mumps_icntl_14 100' it takes
> 3500secs.
>

Send the output of -log_summary for all performance queries. Otherwise we
are just guessing.

    Matt

My command line is: 'mpiexec -np 4 ./ex7 -f1 a2 -f2 b2 -eps_nev 1 -st_type
> sinvert -eps_max_it 5000 -st_ksp_type preonly -st_pc_type lu
> -st_pc_factor_mat_solver_package mumps -mat_mumps_icntl_14 100'
>
> Kindly let me know.
>
> Venkatesh
>
>
>
> On Sat, May 16, 2015 at 7:10 PM, David Knezevic <
> david.knezevic at akselos.com> wrote:
>
>> On Sat, May 16, 2015 at 8:08 AM, venkatesh g <venkateshgk.j at gmail.com>
>> wrote:
>>
>>> Hi,
>>> I am trying to solving AX=lambda BX eigenvalue problem.
>>>
>>> A and B are of sizes 3600x3600
>>>
>>> I run with this command :
>>>
>>> 'mpiexec -np 4 ./ex7 -f1 a2 -f2 b2 -eps_nev 1 -st_type sinvert
>>> -eps_max_it 5000 -st_ksp_type preonly -st_pc_type lu
>>> -st_pc_factor_mat_solver_package mumps'
>>>
>>> I get this error: (I get result only when I give 1 or 2 processors)
>>> Reading COMPLEX matrices from binary files...
>>> [0]PETSC ERROR: --------------------- Error Message
>>> ------------------------------------
>>> [0]PETSC ERROR: Error in external library!
>>> [0]PETSC ERROR: Error reported by MUMPS in numerical factorization
>>> phase: INFO(1)=-9, INFO(2)=2024
>>>
>>
>>
>> The MUMPS error types are described in Chapter 7 of the MUMPS manual. In
>> this case you have INFO(1)=-9, which is explained in the manual as:
>>
>> "–9 Main internal real/complex workarray S too small. If INFO(2) is
>> positive, then the number of entries that are missing in S at the moment
>> when the error is raised is available in INFO(2). If INFO(2) is negative,
>> then its absolute value should be multiplied by 1 million. If an error –9
>> occurs, the user should increase the value of ICNTL(14) before calling the
>> factorization (JOB=2) again, except if ICNTL(23) is provided, in which case
>> ICNTL(23) should be increased."
>>
>> This says that you should use ICTNL(14) to increase the working space
>> size:
>>
>> "ICNTL(14) is accessed by the host both during the analysis and the
>> factorization phases. It corresponds to the percentage increase in the
>> estimated working space. When significant extra fill-in is caused by
>> numerical pivoting, increasing ICNTL(14) may help. Except in special cases,
>> the default value is 20 (which corresponds to a 20 % increase)."
>>
>> So, for example, you can avoid this error via the following command line
>> argument to PETSc: "-mat_mumps_icntl_14 30", where 30 indicates that we
>> allow a 30% increase in the workspace instead of the default 20%.
>>
>> David
>>
>>
>>
>


-- 
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
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20150517/a21db20e/attachment.html>