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Subject: Re: Drawish situations / we need some update in crafty code ! ;)

Author: Robert Hyatt

Date: 08:42:50 09/17/99

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On September 17, 1999 at 07:06:21, Georg v. Zimmermann wrote:

>>
>>Something to experiment with is folding the score in toward zero based upon the
>>50-move counter.  If pieces are coming off and pawns are moving, it is likely
>>that progress is being made.  Once they stop coming off and pawns stop moving,
>>it's very possible that you're headed for a 50-move draw.  I'm not talking about
>>5 or 10 moves, that seems to happen in middlegames, but maybe around 15-20 it
>>should start kicking in slowly.
>
>I like that idea better than my original idea (reducing overall score towards 0
>if all part-evaluation stay the same).
>I would like to see it (as experiment) implemented in Crafty to see the effect.
>I don't think thats hard to do.

I already have lots of draw folding going on.  Chess 4.x and Nuchess were the
first to do what was suggested above... Slate called this a "weariness factor"
in that if the score wasn't slowly going up, getting closer to the 50-move rule
would pull it slowly down.

I don't do this now, but did for a long time way back (in Crafty).  You might
check the comments in main.c to see when it was added and when it was removed,
I don't recall the circumstances when/why now...

But it is definitely a _very_ old idea dating back to the middle 70's at
least...



>
>
>>
>>It's not necessarily true that the draw is going to happen if you just let the
>>program play.  When you get near 50-moves, the program will hit a brick wall --
>>it will see 50-move draw scores.  At this point it might not have enough horizon
>>to try something new, it might allow a draw, or try to make some progress out of
>>panic.  It would be nice to have the program program panic more gradually, so
>>perhaps it can do something before it's had to put its pieces on dumb squares in
>>order to avoid repetitions.
>
>Exactly, there are 2 drawbacks to how it works now:
>
>1.) We humans have to wait 42 moves :-(
>
>2.) Sometimes, in many endgames, the remaining 8 moves arn't enough to try
>something new.



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