> On Nov 21, 2011, at 8:01 AM, Jed Brown wrote: > >> On Mon, Nov 21, 2011 at 04:52, Hui Zhang <buyong.huier at gmail.com> wrote: >> When using DMDAGlobaltoLocal, how can I communicate only the boundary of the >> ghosted domain (with stecil width larger than one)? >> >> Only the ghost values are communicated. The interior is all local. > > I think Hui means DMDALocalToLocalBegin() and DMDALocalToLocalEnd() but > normally one doesn't need this with the PETSc solvers, one only needs the > DMGlobalToLocalBegin/End() > > Barry >
Thank you all! I'm actually implementing domain decomposition methods with restricted communication. From my understanding, DMDALocalToLocalXX is also communicating all ghost values of the second Vec. However, in a restricted way, only the ghost points most far away from the interior are communicated.
