On Sun, Apr 26, 2015 at 11:26:42PM +0200, Petr Baudis wrote: > On Sun, Apr 26, 2015 at 12:17:01PM +0200, remi.cou...@free.fr wrote: > > Hi, > > > > I thought it might be fun to have a tournament on a very large board. It > > might also motivate research into more clever adaptive playouts. Maybe a > > KGS tournament? What do you think? > > That's a cool idea - even though I wonder if 39x39 is maybe too extreme > (I guess the motivation is maximum size KGS allows). > > I think that actually, GNUGo could become stronger than even the top > MCTS programs at some point when expanding the board size, but it's hard > for me to estimate exactly when - if at 25x25 or at 49x49...
I've let play Pachi (in the same configuration that ranks it as 2d on
KGS, but with 15s/move) to play GNUGo for a few games on 25x25 just to
see how it would go. I'm attaching three SGFs if anyone would like to
take a look, Pachi never had trouble beating GNUGo.
Couple of observations:
(i) The speed is only about 60% playouts in the same time compared
to 19x19.
(ii) GNUGo needs to be recompiled to work on larger boards, modify
the MAX_BOARD #define in engine/board.h. (Same with Pachi.)
(iii) As-is, Pachi might get into stack overflow trouble if ran on
larger boards than 25x25.
(iv) 25x25 is the last board size where columns can be represented by
single English alphabet letters. This is the reason for the GTP
limitation, but might trigger other limitations in debug routines etc.
(v) The very first game (not included), Pachi lost completely.
I discovered that my max playout length was 600 moves; bumping that
to 1200 made things boring again.
(vi) Some typically fast operations take much longer on large boards,
e.g. tree pruning (because much wider tree breadth; on 19x19 it's
rarely more than 100ms but it can take seconds on 25x25 for some
reason); this would actually make Pachi occassionally lose byoyomi
periods by a second or two without a manual time allocation adjustment.
And a conjencture:
(vii) (Even) games against GNUGo still aren't interesting on 25x25.
The same factors that might benefit GNUGo compared to MCTS programs
should also benefit DNN players and the difference might be more
visible because a DNN should be much stronger than GNUGo. I wonder
if the oakfoam or any other effort on building an open source DNN
implementation can already play standalone games and how well it works?
--
Petr Baudis
If you do not work on an important problem, it's unlikely
you'll do important work. -- R. Hamming
http://www.cs.virginia.edu/~robins/YouAndYourResearch.html
z3-0.sgf
Description: application/go-sgf
z4-0.sgf
Description: application/go-sgf
z5-0.sgf
Description: application/go-sgf
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