Author: Sune Fischer
Date: 05:18:19 12/05/01
Go up one level in this thread
On December 05, 2001 at 07:49:39, David Rasmussen wrote: >I will count them if you want me to (when I get around to it :), but I don't >really see the point. The point is, that if you have millions of positions, then I would _expect_ the kind of collision numbers you talk about. Right now I don't even know if we agree or not, it depends on this number entirely. It's only if it is very low that 32 bits will work. >Even if there is a lot of positions or even if I have >overlooked something, the fact still remains that a bogus value is returned from >the pawn evaluation when such a collision occur. Do you disagree with that? It sounds right, but are you positive that it should return the same score? I mean what if you have changed from midgame evaluation to endgame evaluation (if you do something like that), then you can't expect the new eval eval() to match an old one. There could be all sort of these changes in the evaluation (or search) as the game develops, it's too complicated for me to say. Instead compare if the 32 bit keys are identical when the 64 keys differ, then that would have been a collision. >I'm >not only talking about Chezzz here, but also about Crafty. I haven't heard of >anybody else in here making the same experiment with their programs, and >reporting the results. Maybe the results are similar for all programs that use >32-bit keys. That is what I suspect. Yes, I too would like someone else (someone more hardcore;) to frase their opinion here, couldn't hurt... :) >>>And whether this rate is "high" or "low", I don't know. Until I >>>am sure it is not "too high", I will stick with a rate of zero. Your argument >>>that there is about 1% chance of collision per game is all well and good. It >>>just doesn't matter, since Crafty have more than 1 collision a second with appx. >>>150 kn/s from the initial position. I am asking several questions: >You don't comment on this. Why? It is pretty essential :) If you really get 300 collisions out of say 10000 positions, then that has to hurt. However I don't think that is what happening at all. -S.
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