Author: Uri Blass
Date: 14:40:56 03/13/04
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On March 13, 2004 at 17:07:36, Dann Corbit wrote: >On March 13, 2004 at 15:51:12, Uri Blass wrote: > >>I redesign my alphabeta and I think to start my alphabeta by trying null move >>because checking for repetition or for hash cut off can be done at the end of >>alpha beta. >> >>When I look at Crafty's code I see that Crafty starts not with null move but >>with checking for repetition and hash. >> >>My question is if there is a soecial reason that I do not understand that Crafty >>does it. >>It seems to me a waste of time to call alphabeta with all the parameters when it >>can be avoided. > >Suppose that you have a hash hit. 1/3 of the time it will be true. Then you >are finished. Just return the answer. > >Suppose that there are lots of repetitions. Then a check for that will give you >an eval of 0 quickly if there is a repeated position draw. > >Repetition count is very cheap. Hash lookup is very cheap. Do as little work >as possible. Crafty is doing it the right way. I agree that they are cheap and I think to have less function calls of search(....) and do the things exactly in the same order. search is a recursive function that calls itself and I suggest to check if there is repetition cutoff before calling itself and not after doing it. Uri
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