> The math escapes me here. I think doubling the playouts gains in the > neighborhood of 70 ELO points. If adding a thread costs 10 ELO, > adding more threads would stop being beneficial after about 14 > threads. Doubling from 7 to 14 would lose 7*10 ELO, equaling the gain > of the extra playouts. After that, adding threads should actually > lose ELO. Yet we see people trying to put together systems with 100s > of CPUs. What am I missing?
Richard Segal (who operates Blue Fuego) has a paper on the upper limit for scaling: http://www.springerlink.com/content/b8p81h40129116kl/ (Sorry, I couldn't find an author's download link for the paper; Richard is on the Fuego list but I'm not sure he is even a lurker here.) I didn't fully understand the methodology, but what I did take away from it (and discussions with Richard) was that though we're satisfied that pure UCT eventually expands all nodes and can solve a position just like minimax, this is not the case once you start adding enhancements such as rave and virtual loss and *parallelizing the algorithm*. Darren -- Darren Cook, Software Researcher/Developer http://dcook.org/work/ (About me and my work) http://dcook.org/blogs.html (My blogs and articles) _______________________________________________ Computer-go mailing list [email protected] http://dvandva.org/cgi-bin/mailman/listinfo/computer-go
