On Aug 9, 2008, at 4:16 AM, terry mcintyre wrote:
----- Original Message ----
I still have this theory that when the level of the program is in
the high-dan reaches, it can take proper advantage of an opening
book. Alas, it may be a few years before enough processoring power
is routinely available to test this hypothesis. I know that we
duffers can always ruin a perfectly good joseki just as soon as we
leave the memorized sequence.
Steve:
why would this be the case?
and where would the book come from?
A thousand years of Go experience? There are many good books on
fuseki and joseki. The challenge is encoding that knowledge flexibly
and using the information appropriately. Compared to earlier
programs, this is one area where the MC programs have taken a step
backwards (or rather, a step toward the center).
my thinking is that unless mogo created the book itself, playing
games like these, against opponents like these, at time controls
like this one, then it couldn't possibly be helpful. and even
then it might not be helpful.
There is an obvious need for adding features to Go programs to make
them play more like humans. The public won't buy programs that play
too strangely, even if they are objectively stronger. The challenges
to MC programs are to:
1. Play more normal looking fuseki.
2. Play joseki moves when available, and use appropriate joseki for
the current board situation.
3. Correct seki detection and evaluation.
4. Some sort of sliding komi so programs still play reasonably when
far ahead or far behind.
4. Toward the endgame, switch to greedier evaluations that maximize
points.
6. Pass instead of filling in territory when all dame are filled.
As far as we could see, Mogo was essentially re-creating book
knowledge the hard way - using millions of playouts times many
seconds to do so. The opening is the same in every game: you start
with an empty board or a given number of handicap stones; why spend
minutes figuring out the best first move, instead of precalculating
that information? As for where it would come from, observation of
thousands of pro games would reveal what they do in a variety of
standard sequences. This information is not useful if the program
cannot play at that level -- lower-level players often botch the
followup to joseki, or choose the wrong joseki for the given whole-
board situation. But a program which uses joseki to guide search
could optimize search.
There have already been programs that have used pro game databases
for opening moves. Howard Landman's Poka springs to mind.
You can reliably say that in certain situations, when you play
move A, even the strongest pro is very likely to respond with one
of a handful of plays; if this knowledge is part of the search
strategy, the search is much more efficient. If you choose to play
some other move, it needs to be demonstrably better than the
standard replies.
A more efficient opening would enable more time to be spent on the
complex middle-game situations.
Indeed. That is especially beneficial for scalable search algorithms.
For example, Orego had a simplistic yet effective fuseki: try to play
on all the star points for the first nine moves. That saved quite a
lot of time and still obtained a reasonable looking opening.
Ian
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