[petsc-users] Error using Metis with PETSc installed with MUMPS

[Barry Smith]

  Pierre,

   Sorry, I was not clear. What I meant was that the PETSc code that calls MUMPS could change the value of ICNTL(6) under certain conditions before calling MUMPS, thus the MUMPS warning might not be triggered. I am basing this on a guess from looking at the MUMPS manual and the warning message that the particular value of ICNTL(6) is incompatible with the given matrix state. But I could easily be wrong.

  Barry


> On Nov 1, 2023, at 1:33 PM, Pierre Jolivet <pierre at joliv.et> wrote:
> 
> Victoria, please keep the list in copy.
> 
>> I am not understanding how can I switch to ParMetis if it does not appear in the options of -mat_mumps_icntl_7.In the options I only have Metis and not ParMetis.
> 
> 
> You need to use -mat_mumps_icntl_28 2 -mat_mumps_icntl_29 2
> 
> Barry, I don’t think we can programmatically shut off this warning, it’s guarded by a bunch of KEEP() values, see src/dana_driver.F:4707, which are only settable/gettable by people with access to consortium releases.
> I’ll ask the MUMPS people for confirmation.
> Note that this warning is only printed to screen with the option -mat_mumps_icntl_4 2 (or higher), so this won’t show up for standard runs.
> 
> Thanks,
> Pierre
> 
>> On 1 Nov 2023, at 5:52 PM, Barry Smith <bsmith at petsc.dev> wrote:
>> 
>> 
>>   Pierre,
>> 
>>    Could the PETSc MUMPS interface "turn-off" ICNTL(6) in this situation so as to not trigger the confusing warning message from MUMPS?
>> 
>>   Barry
>> 
>>> On Nov 1, 2023, at 12:17 PM, Pierre Jolivet <pierre at joliv.et> wrote:
>>> 
>>> 
>>> 
>>>> On 1 Nov 2023, at 3:33 PM, Zhang, Hong via petsc-users <petsc-users at mcs.anl.gov> wrote:
>>>> 
>>>> Victoria,
>>>> "** Maximum transversal (ICNTL(6)) not allowed because matrix is distributed
>>>> Ordering based on METIS"
>>> 
>>> This warning is benign and appears for every run using a sequential partitioner in MUMPS with a MATMPIAIJ.
>>> (I’m not saying switching to ParMETIS will not make the issue go away)
>>> 
>>> Thanks,
>>> Pierre
>>> 
>>> $ ../../../../arch-darwin-c-debug-real/bin/mpirun -n 2 ./ex2 -pc_type lu -mat_mumps_icntl_4 2
>>> Entering DMUMPS 5.6.2 from C interface with JOB, N =   1          56
>>>       executing #MPI =      2, without OMP
>>> 
>>>  =================================================
>>>  MUMPS compiled with option -Dmetis
>>>  MUMPS compiled with option -Dparmetis
>>>  MUMPS compiled with option -Dpord
>>>  MUMPS compiled with option -Dptscotch
>>>  MUMPS compiled with option -Dscotch
>>>  =================================================
>>> L U Solver for unsymmetric matrices
>>> Type of parallelism: Working host
>>> 
>>>  ****** ANALYSIS STEP ********
>>> 
>>>  ** Maximum transversal (ICNTL(6)) not allowed because matrix is distributed
>>>  Processing a graph of size:        56 with           194 edges
>>>  Ordering based on AMF 
>>>  WARNING: Largest root node of size        26 not selected for parallel execution
>>> 
>>> Leaving analysis phase with  ...
>>>  INFOG(1)                                       =               0
>>>  INFOG(2)                                       =               0
>>> […]
>>> 
>>>> Try parmetis.
>>>> Hong
>>>> From: petsc-users <petsc-users-bounces at mcs.anl.gov> on behalf of Victoria Rolandi <victoria.rolandi93 at gmail.com>
>>>> Sent: Tuesday, October 31, 2023 10:30 PM
>>>> To: petsc-users at mcs.anl.gov <petsc-users at mcs.anl.gov>
>>>> Subject: [petsc-users] Error using Metis with PETSc installed with MUMPS
>>>>  
>>>> Hi, 
>>>> 
>>>> I'm solving a large sparse linear system in parallel and I am using PETSc with MUMPS. I am trying to test different options, like the ordering of the matrix. Everything works if I use the -mat_mumps_icntl_7 2  or -mat_mumps_icntl_7 0 options (with the first one, AMF, performing better than AMD), however when I test METIS -mat_mumps_icntl_7 5 I get an error (reported at the end of the email).
>>>> 
>>>> I have configured PETSc with the following options: 
>>>> 
>>>> --with-cc=mpiicc --with-cxx=mpiicpc --with-fc=mpiifort  --with-scalar-type=complex --with-debugging=0 --with-precision=single --download-mumps --download-scalapack --download-parmetis --download-metis
>>>> 
>>>> and the installation didn't give any problems.
>>>> 
>>>> Could you help me understand why metis is not working? 
>>>> 
>>>> Thank you in advance,
>>>> Victoria 
>>>> 
>>>> Error:
>>>> 
>>>>  ****** ANALYSIS STEP ********
>>>>  ** Maximum transversal (ICNTL(6)) not allowed because matrix is distributed
>>>>  Processing a graph of size:    699150 with      69238690 edges
>>>>  Ordering based on METIS
>>>> 510522 37081376 [100] [10486 699150]
>>>> Error! Unknown CType: -1
>>> 
>> 
> 

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