[Computer-go] Kas Cup - results and prizes

Petr Baudis pasky at ucw.cz
Fri Aug 10 12:46:52 PDT 2012


On Fri, Aug 10, 2012 at 09:26:31AM -0700, David Fotland wrote:
> Because my current approach seems to work just as well (or maybe better),
> and I haven't had time to code up a shared try and tune it up to validate
> that assumption.  Chaslot's paper indicates perhaps that not having a shared
> tree is stronger.  My guess is that they are about the same, so it's not
> worth the effort to change.

In Pachi, having a shared tree makes all the difference when scaling up
to more threads. See the graph (really awful one, sorry, it's old!) at

	http://pachi.or.cz/root-vs-shared.png

If you have some information sharing near the root, I imagine it might
be similar to Pachi's distributed engine performance (or just slightly
better). But that is still far behind in scaling compared to the shared
tree in our experience.

P.S.: There are two important things, virtual loss (not necessarily 1
simulation but possibly more) and mainly lockless updates. The latter
also means that sane code should be really easy to modify to use single
shared tree instead of multiple trees.

				Petr "Pasky" Baudis



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