Gian-Carlo Pascutto: <[EMAIL PROTECTED]>: >Olivier Teytaud wrote: > >> Also, there are probably other people interested in combining >> UCT and mpi; I don't know if some people have a more precise idea >> of the level of the MPI+UCT combination than us. Someone ? > >MPI is just a parallel programming model/library, right? > >So the only thing to know is the effective[1] speedup of the MPI >version, and how well UCT scales with increasing timecontrols/speed.
No. Remember UCT is a sequential algorithm. Parallelizing UCT make playouts ineffective. Increasing the number of threads and/or communicating delay decreases the effectiveness of the playouts. With my experiments on a symmetrical threads implementation on a four core SMP system, winning rate against GNU Go decreases from 50.4+-1.1% to 46.7+-1.1%, which corresponds to -25 ELO, where 1.1% are the standard deviations [1]. [1] "A Study on Implementing Parallel MC/UCT Algorithm", GPW 2007 (in Japanese). http://www.geocities.jp/hideki_katoh/publications/gpw2007/gpw07-private.pdf -Hideki >I believe Don has data on the latter and you should have data on the former. > >[1] How much faster you find the correct move. Not interesting is: how >many positions you search per second or how many playouts you do per second. -- [EMAIL PROTECTED] (Kato) _______________________________________________ computer-go mailing list [email protected] http://www.computer-go.org/mailman/listinfo/computer-go/
