NAN : > Dear all, > I created a matrix ( > > MATMPISBAIJ). I want to get the column or row vector after finishing > assemble the matrix. Is there a way to do that in the exist PETSC routine? You can call MatGetRow(). See http://www.mcs.anl.gov/petsc/petsc-as/snapshots/petsc-current/docs/manualpages/Mat/MatGetRow.html Hong