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

[Pierre Jolivet]

> 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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