> On Jun 22, 2016, at 2:06 PM, Barry Smith <bsm...@mcs.anl.gov> wrote: > > > I suggest focusing on asm. Having blocks that span multiple processes seems > like over kill for a smoother ? (Major league overkill) in fact doesn't one > want multiple blocks per process, ie. pretty small blocks.
And with lots of small blocks, remember to configure with --with-viewfromoptions=0. :-) -- Boyce > > Barry > >> On Jun 22, 2016, at 7:51 AM, Mark Adams <mfad...@lbl.gov> wrote: >> >> I'm trying to get block smoothers to work for gamg. We (Garth) tried this >> and got this error: >> >> >> - Another option is use '-pc_gamg_use_agg_gasm true' and use >> '-mg_levels_pc_type gasm'. >> >> >> Running in parallel, I get >> >> ** Max-trans not allowed because matrix is distributed >> ---- >> >> First, what is the difference between asm and gasm? >> >> Second, I need to fix this to get block smoothers. This used to work. Did >> we lose the capability to have blocks that span processor subdomains? >> >> gamg only aggregates across processor subdomains within one layer, so maybe >> I could use one layer of overlap in some way? >> >> Thanks, >> Mark >>
