Author: Uri Blass
Date: 06:56:11 05/22/03
Go up one level in this thread
On May 22, 2003 at 09:48:11, José Carlos wrote: >On May 22, 2003 at 09:06:24, Uri Blass wrote: > >>On May 22, 2003 at 08:41:56, Ulrich Tuerke wrote: >> >>>On May 22, 2003 at 06:08:47, José Carlos wrote: >>> >>>>On May 22, 2003 at 01:01:38, Robin Smith wrote: >>>> >>>>>Often programs will underpromote a pawn in situations where they think capturing >>>>>the (under)promoted piece is still the best reply. Can anyone give an example >>>>>from an actual game where this underspromotion cost the computer a 1/2 point? >>>>> >>>>>Robin >>>> >>>> I can't recall any game with this problem, but it's really easy to fix. I >>>>simply order the promotions so that promoting to queen gets searched first. >>> >>>Isn't everybody doing this anyway ? >>>Uli >> >>I do it and I strongly believe that shredder does it >>but it is not enough to prevent the problem. >> >>Movei does not use hash tables for pruning and I >>think that it may be interesting to read an explanation >>for the behaviour of shredder or another program >>that considers c1R as best. >> >> >>I think that in order to prevent the problem a program >>can ask itself if an underpromotion makes sense before >>considering it and I plan to add it in the future >> >>I do not need hash tables and killer moves >>are enough for it. >> >>I simply need to tell the program that if the killer move of >>queen promotion is capturing it then it should not consider underpromotions. >> >>Uri > > You shouldn't consider captures as killers, because it's a waste, as you're >most probably searching good captures before killers. Promotions should be >considered as captures in this regard. > > José C. Yes You are right and I do not do it. I did not think about what I exactly do in movei when I wrote the post but only about the general idea that killer is the move that refute the opponent move. It is still be possible to remember special killer for promotions that may be captures and to look at the special killer moves before doing under promotions. Uri
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