Author: Robert Hyatt
Date: 06:22:55 01/16/02
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On January 16, 2002 at 00:08:19, martin fierz wrote: >On January 15, 2002 at 23:38:54, Robert Hyatt wrote: > >>On January 15, 2002 at 21:50:52, martin fierz wrote: >> >>>aloha, >>> >>>i have a question about repetitions, and it's only about the search itself, not >>>about the game history: in my checkers program, to find repetition draws i keep >>>track of the hash keys of the current variation, and if i find that the key for >>>the current position has already ocurred before in the search, i return zero >>>without searching further. i think this is the standard implementation?! >>>anyway, i am wondering about the following problem: imagine you are searching a >>>variation, and in the end you make a repetition. the program will stop searching >>>there in the tree and assign the position a value of 0. now imagine that you >>>have a different path of moves without a repetition which ends up at that node, >>>probes the hashtable and returns 0. is this just my imagination, or can this >>>happen and can it be bad? >>> >>>cheers >>> martin >> >> >>It can happen. As can the inverse, where you retrieve a real score from the >>hash table but you can never reach the position because there is a three-fold >>repetition between where you are and where you are going... > >so... is there a solution to this problem? or is it just tacitly assumed that it >"never happens"? > >cheers > martin You can disable hashing. Or you can hash all path information which will effectively disable transpositions which will disable hashing. :)
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