[Computer-go] replacing dynamic komi with a scoring function
stefan.kaitschick at hamburg.de
Sun Jan 8 16:22:26 PST 2012
The most successful scoring function sofar is the win/lose function.
Sigmoid functions and other schemes have been tried, but none have
surpassed or even equaled the simple step function.
dynamic komi is widely used by bots in handicap games.
An initial artificial komi burden is placed on black which is incrementally
reduced to zero during the game.
This gives the bot a "more realistic" goal as white, and a motivation not
to play slackly as black.
One of the traps of dynamic komi is that the bot will be willing to
simplify as white, if only he is catching up quickly enough, as specified
by the dynamic komi.
The bot can then find itself in a played out position, where catching up
the final margin proves impossible.
Conceptually, it would be nice to search at several different komi levels,
from the komi needed for a 50% winrate(honest play), to the correct komi.
If these values are added up(possibly weighted in some way), the result
should be the most honest move that still has long term perspective.
Doing this would have an obvious drawback though: less playouts per komi
level, probably resulting in an overall weaker game.
So here is my idea: introduce a scoring function that has the 0-border at
the komi needed for a 50% winrate, and the 1-border at +1(as in the step
(this would be if the bot is trailing, otherwise from 0 to komi)
I have no idea what would be the proper function between those points,
maybe a half sigmoid function, possibly just a straight line.
The idea is not to maximize the score, but to capture the results of
different komi levels in a single search, so as not to lose playouts.
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