> On Mar 20, 2017, at 6:07 PM, Daralagodu Dattatreya Jois, Sathwik Bharadw > <[email protected]> wrote: > > Hey all, > > I am using AIJ matrix to solve Laplace problem in finite element framework. > To apply Neumann boundary conditions I need to obtain values of first and > last few columns and subtract it with the corresponding right hand side > vector. I understand that MatGetColumnVector andMatGetValues are not > collective. Is there any other alternative petsc calls to achieve this in > parallel?
Hmm, I think you mean non-zero Dirichlet boundary conditions. In that case the recommended approach is calling MatZeroRows() or if you want to preserve symmetry MatZeroRowsColumns(). There are also MatZeroRowsLocal() and MatZeroRowsColumnsLocal() and a few other variants. Barry > > Thanks, > Sathwik
