Dear PETSc developers I got an error with MatZeroRowsColumns, which said there was one missing diagonal entries
This is the full log message that I got: Mat Object: 2 MPI processes type: mpiaij rows=41064, cols=41064, bs=4 total: nonzeros=5.66069e+06, allocated nonzeros=1.28112e+07 total number of mallocs used during MatSetValues calls =0 using I-node (on process 0) routines: found 5647 nodes, limit used is 5 [0]PETSC ERROR: --------------------- Error Message -------------------------------------------------------------- [0]PETSC ERROR: Object is in wrong state [0]PETSC ERROR: Matrix is missing diagonal entry in row 7 [0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting. [0]PETSC ERROR: Petsc Release Version 3.6.3, Dec, 03, 2015 [0]PETSC ERROR: python on a arch-linux2-cxx-opt named bermuda by hbui2 Wed Jan 13 10:27:42 2016 [0]PETSC ERROR: Configure options --with-shared-libraries --with-debugging=0 --with-pic --with-clanguage=cxx --download-fblas-lapack=yes --download-ptscotch=yes --download-metis=yes --download-parmetis=yes --download-scalapack=yes --download-mumps=yes --download-hypre=yes --download-ml=yes --download-klu=yes --download-pastix=yes --with-mpi-dir=/opt/openmpi-1.10.1_thread-multiple --prefix=/home/hbui/opt/petsc-3.6.3 [0]PETSC ERROR: #1 MatZeroRowsColumns_SeqAIJ() line 1901 in /media/NEW_HOME/sw2/petsc-3.6.3/src/mat/impls/aij/seq/aij.c [0]PETSC ERROR: #2 MatZeroRowsColumns() line 5476 in /media/NEW_HOME/sw2/petsc-3.6.3/src/mat/interface/matrix.c [0]PETSC ERROR: #3 MatZeroRowsColumns_MPIAIJ() line 908 in /media/NEW_HOME/sw2/petsc-3.6.3/src/mat/impls/aij/mpi/mpiaij.c [0]PETSC ERROR: #4 MatZeroRowsColumns() line 5476 in /media/NEW_HOME/sw2/petsc-3.6.3/src/mat/interface/matrix.c [1]PETSC ERROR: --------------------- Error Message -------------------------------------------------------------- [1]PETSC ERROR: Object is in wrong state [1]PETSC ERROR: Matrix is missing diagonal entry in row 7 [1]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting. [1]PETSC ERROR: Petsc Release Version 3.6.3, Dec, 03, 2015 [1]PETSC ERROR: python on a arch-linux2-cxx-opt named bermuda by hbui2 Wed Jan 13 10:27:42 2016 [1]PETSC ERROR: Configure options --with-shared-libraries --with-debugging=0 --with-pic --with-clanguage=cxx --download-fblas-lapack=yes --download-ptscotch=yes --download-metis=yes --download-parmetis=yes --download-scalapack=yes --download-mumps=yes --download-hypre=yes --download-ml=yes --download-klu=yes --download-pastix=yes --with-mpi-dir=/opt/openmpi-1.10.1_thread-multiple --prefix=/home/hbui/opt/petsc-3.6.3 [1]PETSC ERROR: #1 MatZeroRowsColumns_SeqAIJ() line 1901 in /media/NEW_HOME/sw2/petsc-3.6.3/src/mat/impls/aij/seq/aij.c [1]PETSC ERROR: #2 MatZeroRowsColumns() line 5476 in /media/NEW_HOME/sw2/petsc-3.6.3/src/mat/interface/matrix.c [1]PETSC ERROR: #3 MatZeroRowsColumns_MPIAIJ() line 908 in /media/NEW_HOME/sw2/petsc-3.6.3/src/mat/impls/aij/mpi/mpiaij.c [1]PETSC ERROR: #4 MatZeroRowsColumns() line 5476 in /media/NEW_HOME/sw2/petsc-3.6.3/src/mat/interface/matrix.c The problem is, before calling MatZeroRowsColumns, I searched for zero rows and set the respective diagonal: PetscInt Istart, Iend; MatGetOwnershipRange(rA.Get(), &Istart, &Iend); // loop through each row in the current partition for(PetscInt row = Istart; row < Iend; ++row) { int ncols; const PetscInt* cols; const PetscScalar* vals; MatGetRow(rA.Get(), row, &ncols, &cols, &vals); PetscScalar row_norm = 0.0; for(int i = 0; i < ncols; ++i) { PetscScalar val = vals[i]; row_norm += pow(val, 2); } row_norm = sqrt(row_norm); if(row_norm == 0.0) { for(int i = 0; i < ncols; ++i) { PetscInt col = cols[i]; if(col == row) { MatSetValue(rA.Get(), row, col, 1.0, INSERT_VALUES); } } } MatRestoreRow(rA.Get(), row, &ncols, &cols, &vals); } // cached the modification MatAssemblyBegin(rA.Get(), MAT_FINAL_ASSEMBLY); MatAssemblyEnd(rA.Get(), MAT_FINAL_ASSEMBLY); This should set all the missing diagonal for missing rows. But I could not figure out why the error message above happen. Any ideas? Regards Giang