OK, thanks to the both of you. It now makes more sense to me why you do all these copying around in PCTELESCOPE, e.g., http://www.mcs.anl.gov/petsc/petsc-current/src/ksp/pc/impls/telescope/telescope.c.html#line469 <http://www.mcs.anl.gov/petsc/petsc-current/src/ksp/pc/impls/telescope/telescope.c.html#line469>.
Pierre > On 10 Sep 2018, at 5:14 AM, Jed Brown <[email protected]> wrote: > > "Smith, Barry F." <[email protected]> writes: > >> It is not possible to do this. When communicating parallel to parallel >> the communicator for both vectors must be the same communicator. > > Note that one can use VecPlaceArray as part of the communication so you > don't need a copy to get it on a different subcommunicator. Perhaps > that could be made automatic at a future date, after the ongoing > VecScatter refactoring has completed.
