<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Jun 22, 2016, at 2:06 PM, Barry Smith <<a href="mailto:bsmith@mcs.anl.gov" class="">bsmith@mcs.anl.gov</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><br class=""> 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.<br class=""></div></blockquote><div><br class=""></div>And with lots of small blocks, remember to configure with --with-viewfromoptions=0. :-)</div><div><br class=""></div><div>-- Boyce</div><div><font color="#f5f5f5" face="Menlo" size="2" class=""><span style="background-color: rgb(0, 0, 0);" class=""><br class=""></span></font><blockquote type="cite" class=""><div class=""><br class=""> Barry<br class=""><br class=""><blockquote type="cite" class="">On Jun 22, 2016, at 7:51 AM, Mark Adams <<a href="mailto:mfadams@lbl.gov" class="">mfadams@lbl.gov</a>> wrote:<br class=""><br class="">I'm trying to get block smoothers to work for gamg. We (Garth) tried this and got this error:<br class=""><br class=""><br class=""> - Another option is use '-pc_gamg_use_agg_gasm true' and use '-mg_levels_pc_type gasm'.<br class=""><br class=""><br class="">Running in parallel, I get<br class=""><br class=""> ** Max-trans not allowed because matrix is distributed<br class=""> ----<br class=""><br class="">First, what is the difference between asm and gasm?<br class=""><br class="">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?<br class=""><br class="">gamg only aggregates across processor subdomains within one layer, so maybe I could use one layer of overlap in some way?<br class=""><br class="">Thanks,<br class="">Mark<br class=""><br class=""></blockquote></div></blockquote></div><br class=""></body></html>