Author: Sune Fischer
Date: 10:06:32 09/25/01
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On September 25, 2001 at 11:57:36, Robert Hyatt wrote: >>>>See, if you make a hash the size of 2^64 and fill it (!) >>>>then you have no free keys left! >>>>The next position key you generate will match one >>>>of those in the table with 100% certainty! > > >That is correct. But the way zobrist works, it is far more likely that >that position is a _real_ match rather than a false match... So that once >you fill the table, you can't assume that _every_ probe from that point >forward is a false match. very few will be in fact... Well no, see my other post: http://www.icdchess.com/forums/1/message.shtml?190349 You forget that the problem here is, that you would not be able to update any entries, and so as the game evolves, new positions will occur and old ones will never be re-seached. This will lead to collisions. I think this discussion is a waste of our time now. Can we agree to the following: 1) Double the hash size and you double the probability of a collision. 2) With current computers it is still _extremely_ unlikely to have a collision, much less one that would lead to a bad move. It's just I have not seen you agree to number 1 anywhere. Do you agree to number 1? -S.
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