[petsc-users] MatFindOffBlockDiagonalEntries error

[Eda Oktay]

Hi all,

I am trying to find off block diagonal entries of a matrix and I am
trying to use MatFindOffBlockDiagonalEntries. However, although my
matrix is not NULL, I am getting an error message as follows:

1]PETSC ERROR: --------------------- Error Message
--------------------------------------------------------------
[1]PETSC ERROR: [2]PETSC ERROR: --------------------- Error Message
--------------------------------------------------------------
[2]PETSC ERROR: Null argument, when expecting valid pointer
[2]PETSC ERROR: Null Object: Parameter # 1
[2]PETSC ERROR: See
http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble
shooting.
[2]PETSC ERROR: Petsc Release Version 3.11.1, Apr, 12, 2019
[2]PETSC ERROR: [3]PETSC ERROR: --------------------- Error Message
--------------------------------------------------------------
[3]PETSC ERROR: Null argument, when expecting valid pointer
[3]PETSC ERROR: Null Object: Parameter # 1
[3]PETSC ERROR: See
http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble
shooting.
[3]PETSC ERROR: Null argument, when expecting valid pointer
[1]PETSC ERROR: Null Object: Parameter # 1
[1]PETSC ERROR: See
http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble
shooting.
[1]PETSC ERROR: Petsc Release Version 3.11.1, Apr, 12, 2019
[1]PETSC ERROR:
./approx_cut_deneme_clustering_son_final_edgecut_without_parmetis on a
arch-linux2-c-debug named b342.wls.metu.edu.tr by edaoktay Fri Jun 19
18:19:11 2020
[1]PETSC ERROR: Configure options --download-mpich --download-openblas
--download-slepc --download-metis --download-parmetis --download-chaco
--with-X=1
[1]PETSC ERROR: #1 ISGetSize() line 510 in
/home/edaoktay/petsc-3.11.1/src/vec/is/is/interface/index.c
[1]PETSC ERROR:
./approx_cut_deneme_clustering_son_final_edgecut_without_parmetis on a
arch-linux2-c-debug named b342.wls.metu.edu.tr by edaoktay Fri Jun 19
18:19:11 2020
[2]PETSC ERROR: Configure options --download-mpich --download-openblas
--download-slepc --download-metis --download-parmetis --download-chaco
--with-X=1
[2]PETSC ERROR: #1 ISGetSize() line 510 in
/home/edaoktay/petsc-3.11.1/src/vec/is/is/interface/index.c
[2]PETSC ERROR: #2 MatFindOffBlockDiagonalEntries_MPIAIJ() line 211 in
/home/edaoktay/petsc-3.11.1/src/mat/impls/aij/mpi/mpiaij.c
[2]PETSC ERROR: #2 MatFindOffBlockDiagonalEntries_MPIAIJ() line 211 in
/home/edaoktay/petsc-3.11.1/src/mat/impls/aij/mpi/mpiaij.c
[1]PETSC ERROR: #3 MatFindOffBlockDiagonalEntries() line 10502 in
/home/edaoktay/petsc-3.11.1/src/mat/interface/matrix.c
#3 MatFindOffBlockDiagonalEntries() line 10502 in
/home/edaoktay/petsc-3.11.1/src/mat/interface/matrix.c
Petsc Release Version 3.11.1, Apr, 12, 2019
[3]PETSC ERROR:
./approx_cut_deneme_clustering_son_final_edgecut_without_parmetis on a
arch-linux2-c-debug named b342.wls.metu.edu.tr by edaoktay Fri Jun 19
18:19:11 2020
[3]PETSC ERROR: Configure options --download-mpich --download-openblas
--download-slepc --download-metis --download-parmetis --download-chaco
--with-X=1
[3]PETSC ERROR: #1 ISGetSize() line 510 in
/home/edaoktay/petsc-3.11.1/src/vec/is/is/interface/index.c
[3]PETSC ERROR: #2 MatFindOffBlockDiagonalEntries_MPIAIJ() line 211 in
/home/edaoktay/petsc-3.11.1/src/mat/impls/aij/mpi/mpiaij.c
[3]PETSC ERROR: #3 MatFindOffBlockDiagonalEntries() line 10502 in
/home/edaoktay/petsc-3.11.1/src/mat/interface/matrix.c

And the program is still running.

The part of my program is :

  Mat Ais;
  MatCreateSubMatrix(A,idUi,idUi,MAT_INITIAL_MATRIX,&Ais);
  ISSetPermutation(idUi);
  MatPermute(Ais,idUi,idUi,&PL);
  IS offd;
  MatFindOffBlockDiagonalEntries(PL,&offd);

Since there isn't any examples for this function, I couldn't
understand what should I do. Since it says in the error that it is
about parameter 1, the matrix, I don't know how to solve the problem.
My matrix PL is parallel sparse. I know there shouldn't be any problem
in PL since I can view PL by using MatView.

Thanks!

Eda