Re: [computer-go] Dynamic komi in commercial programs

2009-07-11 Thread terry mcintyre
The go-playing literature offers a bit of advice: when ahead, make moves which 
simplify the game and preserve your advantage. When behind, take some risks to 
grab more than you are "entitled" to - but not too many. Computer programs seem 
bizarre in this regard, they tend to play quite unsatisfactory moves when 
behind. It would be more attractive to see the computer preserve its advantage, 
the better to spring when one's opponent lapses.


A complex seki was recently posted. Magnus explained that his program does not 
understand the seki per se, but finds the correct move through several 
intricately-meshed rules which prune bad moves. He's not entirely sure of the 
correctness of those rules - that is, whether they apply to all cases, or 
merely most cases. At the single-digit-kyu level, inducing sekis is not 
unusual; it is basic for dan-level players.

Some high-dan players prefer to give a large negative komi instead of handicap 
stones; the game mechanics are closer to those of an even game. The stronger 
player gains incrementally with every suboptimal move by the weaker; 
eventually, the advantage of the negative komi dissipates.

When can we train our programs, instructing them "don't do that, it will only 
hurt you?"



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Re: [computer-go] Dynamic komi in commercial programs

2009-07-11 Thread Don Dailey
I think we should open up to other ideas, not just dynamic komi
modification.   In fact that has not proved to be a very fruitful technique
and I don't understand the fascination with it.

First we identify what it is we are trying to accomplish.  You mentioned
improving the strength of MCTS go programs in handicap games,  but many
people point to the ugly style of play.

Here is something to think about in more theoretical terms.   Define what
good play is.   To me there is no satisfying definition - the CORRECT
definition is not the one that we intuitively expect.   For instance,   if
you are in a dead lost position,  every move you play is a losing move.
How can you say any particular move is better?To me a good move is any
move that preserve the best game theoretic result possible at this point in
the game.   That means in a lost position ALL moves are good moves because
they all preserve the loss.It's an odd way to look at it, but it makes
more sense in won positions, as only a few or even 1 move preserves a
win.

The intuitive definition that we really mean when we talk about good play is
to play in such a way as to increase our chances of winning against fallible
opponents.In fact,  what is good is technically (and practically)
defined by WHO your opponent is.

It appears that dynamic komi modification does not even help you win against
fallible opponents,  so we should probably look to opponent modeling (since
that is really what we are asking for - especially with handicap games.)

Another definition for good play is one that could be added to our MCTS
programs.   Play the move which preserves the best possible total point
score. That means even in a dead lost position we will fight for every
point on the board.

Why doesn't this code up well with go programs?   From a purely theoretical
view, it is a "perfect" goal in the sense that if it is followed perfectly,
it will perform the same as simply playing for the win against perfect
opponents. Part of the answer may be that it requires more skill.
There are fewer moves (in general) that will accomplish this goal than there
is in winning the game.

It would not suprise me, although I haven't specifically tested this,  if
this led to stronger play than dynamic komi modification.

Then there is the possibility of a hybrid between the two. A fourth
possibility is to gently impose some higher order knowledge on the search -
try to make the tree branch out with moves that WE consider stronger (by the
practical defintion, not the correct definition.) Probably with only a
little help, moves which are other equal but we like better can  be coerced
into being the ones expanded on first and thus end up being the ones chosen
by the MC program.We could do this by letting some conventional program
choose the best move(s) and give them a few bogus wins to make the tree
begin with the moves we would prefer.

There a probably tons of possibilities. What does Many Faces do?   Does
it play more naturual?  I ask because I know that Dave is more concerned
about the marketability of the program and is interested and concerned about
such things.

- Don




On Sat, Jul 11, 2009 at 10:26 AM, "Ingo Althöfer" <3-hirn-ver...@gmx.de>wrote:

> One of the difficult questions is if (or better how)
> dynamic komi can be used to improve the strength of
> MCTS go programs in handicap games (both cases being
> "interesting": computer on strong side - and -
> computer on weak side).
>
> Especially, there are several normal go players
> ("non-programmers") who are interested in this topic
> and who feel that the current non-activity on this
> question is unsatisfactorily.
> Stefan Kaitschick (German 5-dan amateur, EGF-rating
> 2439) is in some sense the most prominent amongst them.
>
> I think that it would be a real chance for the programmers
> to use the interest and creativity of such people. This might
> happen for instance in the following way: include a
>
>"simple komi-modification button"
>
> in your program (or a pair of buttons, one for +, one for -)
> which can be used by simple mouse clicks. Of course, all the
> time the true value of komi should also be shown. You programmers
> would probably be surprised to see what creative users would find
> out when playing around with such a feature.
>
> Ingo.
> --
> Neu: GMX Doppel-FLAT mit Internet-Flatrate + Telefon-Flatrate
> für nur 19,99 Euro/mtl.!* http://portal.gmx.net/de/go/dsl02
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[computer-go] Dynamic komi in commercial programs

2009-07-11 Thread Ingo Althöfer
One of the difficult questions is if (or better how)
dynamic komi can be used to improve the strength of 
MCTS go programs in handicap games (both cases being
"interesting": computer on strong side - and -
computer on weak side).

Especially, there are several normal go players
("non-programmers") who are interested in this topic
and who feel that the current non-activity on this
question is unsatisfactorily.
Stefan Kaitschick (German 5-dan amateur, EGF-rating
2439) is in some sense the most prominent amongst them.

I think that it would be a real chance for the programmers
to use the interest and creativity of such people. This might 
happen for instance in the following way: include a 

"simple komi-modification button" 

in your program (or a pair of buttons, one for +, one for -) 
which can be used by simple mouse clicks. Of course, all the 
time the true value of komi should also be shown. You programmers 
would probably be surprised to see what creative users would find 
out when playing around with such a feature.

Ingo.
-- 
Neu: GMX Doppel-FLAT mit Internet-Flatrate + Telefon-Flatrate
für nur 19,99 Euro/mtl.!* http://portal.gmx.net/de/go/dsl02
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