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

[Barry Smith]

  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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