Go has a bigger branching factor than chess, as it starts with an
empty board of 19x19, versus chess a loaded board of 8x8.
The first few moves in go decide the outcome of the game already, as
the rest is just a 'playout' of the first few moves. So what matters
most is the first few moves in the game.
It is easier to search selective in go than it is in chess. In chess
selective searching is really tough to get to work well.
In go you can throw away majority of the moves with near 100%
sureness, some even with 100% sureness.
Reason why chessprograms play so well is simply money and popularity
of the game.
Chess computers in the 80s and start 90s, used to export to 106
countries. I remember talking about producing a dedicated chesscomputer,
and usually 100000 of them get printed. A minimum of 20000 pieces is
needed to heat up the production line (Hong Kong, China).
There is no go computers AFAIK, for simple reason that the only
nation where you can sell your product is Japan. The 3 main nations
where
go gets played is China, Korea, Japan. So only Japan you could sell
some if you have entrance to its very close market.
In fact there is even a company that claims to have the rights on all
human go games.
At my chat is someone, Gian-Carlo Pascutto, whose program Leela you
can buy.
It is as we speak the strongest commercial go program on planet earth
that you can buy.
His engine focuses upon search, its knowlede is rather simplistic.
He has a normal job just like you have one.
So this is a sparetime written engine.
Computerchess engines used to be fulltime work. When someone is
jobless like me, you again work for a few months fulltime at it.
There is 500 chess engines to compete with or so.
In go the competition is very limited, only recently more engines are
there. Most programmed by non-asian programmers.
Not even from Asian decent.
It's all about how much money you want to put in research. Would go
have been the game been played in 106 nations and chess in just 3
from which only 1 has money and is a closed market, then we would be
speaking now about a computer-go world champion program and wondering
what makes computer chess so hard.
In that case I would write then that if more money had been put at
chess, that those engines would be stronger than the go engines.
Don't count at it that the big supercomputers make any chance in go,
neither in chess. The quality of the program is most important.
As soon as you massively parallellize a strong engine, now *that*
makes sense.
Vincent
On Jun 24, 2008, at 6:20 PM, Peter St. John wrote:
Programming a computer to play Go (an Asian strategy boardgame) has
been difficult; some people say it's proof that Go is better or
harder than chess, since computers can beat masters at chess but
struggle at Go. (I think that statistically a game of go is about
equivalent to a two-game match of chess; both games empty your
brain quickly of course). My view is that while go may be somewhat
harder to reduce to tree-searching, the main advantage of computer
chess was an early start, e.g. von Neumann.
This article:
http://www.usgo.org/resources/downloads/CogApdx%20II-2.pdf
describes recent trends in computer Go and mentions a 32-node
cluster, 8 cores per node. Apparently MPI parallelization is recent
for them and they are making good progress.
Peter
The game Go: http://en.wikipedia.org/wiki/Go_%28game%29
AGA (American Go Association): http://www.usgo.org
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