Author: Robert Hyatt
Date: 20:39:45 01/15/02
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On January 15, 2002 at 22:16:20, Derek Mauro 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? > >Your hashtable should have a value in it from the first time you used the >evaluation function. If the position repeats, you just have search return 0. >You don't record scores in the hashtable that are the result of a repetition, >you leave the original score. > >Derek >> That leads to results just as wrong as what he described... you fail to recognize draws... >>cheers >> martin
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