<div dir="ltr"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small">Dear Petsc users,</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small">I would like to use BoomerAMG preconditioner for a system of PDEs, but we are interested in setting some of BoomerAMG options to <span style="font-family:arial,sans-serif">use the nodal systems coarsening.</span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small"><span style="font-family:arial,sans-serif"><br></span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small"><span style="font-family:arial,sans-serif">From the HYPRE/BoomerAMG manual, I found out that I have to use the following functions:</span></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small"><span style="font-family:arial,sans-serif"><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">HYPRE_BoomerAMGSetNodal<br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">HYPRE_BoomerAMGSetNumFunctions</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">HYPRE_BoomerAMGSetDofFunc <br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Looking at the source code (src/ksp/pc/impls/hypre/hypre.c) I've found the call to the first one, but not for the other two, where I must specify the ordering of my dofs in my problem.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">I would appreciate any help on this.</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif"><br></div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Best regards,</div><div class="gmail_default" style="font-family:arial,helvetica,sans-serif">Bernardo</div></span></div></div>