Of course, what I was missing was that you can't call ident_zeros on an unfinalized matrix as it depends on MatGetRows with the petsc backend. So calling a routine that adds zeros to the diagonal is necessary before finalizing before calling ident_zeros.
Of course, what I was missing was that you can't call ident_zeros on an unfinalized matrix as it depends on MatGetRows with the petsc backend. So calling a routine that adds zeros to the diagonal is necessary before finalizing before calling ident_zeros.