>The purpose of a handicap games is to allow a 50% chance of either
>contestant winning. .. Programs do not care,
Are you sure?-) I haven't got round to moving beyond a plain MC bot yet,
where the effect is rather striking, but less naive bots also depend on win-rate
for their move evaluations.
The effect is that the bot is only "interested" in a narrow range of fairly
balanced games: if it gets too far behind, or too far ahead, its play becomes
fairly random. The reason being that small differences in score may not
sufficiently affect the win/lose ratio to be distinguishable (it would take
longer sequences of such better moves to change the win/lose outcome),
so good and bad moves are getting lumped together in the evaluation.
However, handicap games are rather different from non-handicap games,
and bots don't care how a balance is achieved, so one might simply use
numeric handicaps. Only that a large numeric handicap will have a bad
effect on win-rate-based bots' evaluation abilities - the weaker bot,
seeing a large numeric advantage, will play even more weakly. So one
might have to phase in awareness of handicap gradually, adjusting it
during the game (as the stronger bot gets ahead in the game, more of the
handicap gets added to keep the evaluation and gameplay interesting).
Which does sound rather complicated. But it reminds me of a suggestion
I made a long time ago for human games(*), which might be easier to adopt
in this context: when a player/bot is far enough ahead that even a double
move by its opponent will at best catch up, the stronger player can simply
pass. At the end of the game, any difference in the number of passes is
counted as handicap, and recorded together with the plain score/result.
It would allow stronger bots to keep weaker bots in play for longer,
when the remainder of the game would otherwise be a continued
sigh "oh, if its programmer had only implemented early resign..".
It would also allow weaker bots and their authors to get more out of
playing stronger bots (provided that authors actually study game
records, not just result statistics) - instead of "that game was really
lost, but my bot didn't know, so it just kept playing random moves"
it would be "hmm, to make that game even close, our opponent
had to pass 5 times, lets look at the pass moves and what went
wrong to make them possible".
Just another idea,
Claus
(*) the context was "teaching" games: being rather a beginner myself,
and trying to interest newcomers to play the game, I never felt
confident in guessing useful handicaps, let alone explaining the
different play required to make use of handicap stones. Not to
mention that beginner strengths are rather variable.
So what I did instead was to start out evenly, then deliberately
throw in less efficient moves when I thought I was getting too far
ahead (an entirely new source of blundering opportunities, btw;-).
This was often accompanied by trying to explain to my opponent,
within the limited range of my game knowledge, why I thought
that their moves weren't as efficient as mine, and what they
might have tried instead to achieve their aims.
The discussions were really useful and interesting (the target
audience at the time being academics with incurable affinity
for discussing and reasoning), but the slow-downs kept the
games going for longer (also: realistic for long stretches, and
highlighting opportunities for discussions in between, at the
slow-down points). The approach also seemed to take the
emphasize away from winning, towards learning/thinking/
having fun with exploring the game.
_______________________________________________
computer-go mailing list
computer-go@computer-go.org
http://www.computer-go.org/mailman/listinfo/computer-go/
