[Computer-go] MCTS playouts per second

Hideki Kato hideki_katoh at ybb.ne.jp
Wed Oct 26 16:42:43 PDT 2011

Zen has very slow (but very smart) heavy playout, about 1 kpo/s on a 3 
GHz Intel Core2 core.  One important "tenuki" for speed-up is to check 
the legality of moves _after_ selecting a move, i.e., don't check the 
legality of all moves before choosing a move.


Scott Christensen: <CAHuTwaxAW=44AXc6hhrtbYMxfJ079u=jxVjp=yrWcRB6j-Vy9A at mail.gmail.com>:
>Just want to check what the expected playout performance is of well
>tuned monte-carlo engines?  My MCTS engine is averaging apx 3,500
>lightweight playouts per second on a single i5 32 bit cpu.  Any
>suggestions on very efficient source code examples for fast
>monte-carlo playouts?
>I've spent a lot of time comparing recursive group formation vs
>non-recursive but it doesn't seem to make a big difference.  It seems
>that updating the list of likely moves after every play with something
>similar to the mogo probability rules is the most time consuming part
>as I currently recalculate the probabilities of moves at every empty
>point on the board each turn. It seems necessary if one doesn't want
>to handle all the exceptions to keeping the previous turn's play
>Also any thoughts on combining pattern scoring and other conventional
>techniques together with a UCT tree?   If two branches have very
>similar simulated win ratios could one use other factors to choose the
>best branch?  It seems if there is a very wide branching such as at
>the beginning of the game, there is a lot of room to add other
>heuristics to choosing the best move when monte-carlo scores are
>within range of expected error.
>Computer-go mailing list
>Computer-go at dvandva.org
Hideki Kato <mailto:hideki_katoh at ybb.ne.jp>

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