Author: Uri Blass
Date: 08:09:16 12/26/02
Go up one level in this thread
On December 26, 2002 at 10:55:55, Robert Hyatt wrote: >On December 26, 2002 at 01:34:46, Miguel A. Ballicora wrote: > >>On December 25, 2002 at 15:18:29, Robert Hyatt wrote: >> >>>On December 25, 2002 at 10:46:17, Dieter Buerssner wrote: >>> >>>>On December 24, 2002 at 23:05:09, Robert Hyatt wrote: >>>> >>>>>[...] Why don't you go read Knuth/Moore's paper on >>>>>alpha beta. There you will find that move ordering does _not_ affect the >>>>>final score, only the size of the tree. Something every senion-level computer >>>>>science student should know. >>>> >>>>I think, in most modern chess programs, move ordering can affect the final >>>>score. Reasons can be extensions/pruning/hash tables. >>>> >>>>Regards, >>>>Dieter >>> >>>If move ordering affects extensions or pruning, _something_ is broken. As >>>that violates the basic premise of alpha/beta... >> >>I am really surprised by this statement. Any pruning or extension that depends >>on alpha will be affected by the move ordering. With different move ordering, >>the same position might face different bounds, hence, different extensions could >>be triggered. >> >That is the point. Do you want to find something by serendipity? I don't. >I want consistent behavior every time. And if something is dependent on move >ordering, it is dependent on luck. IE do you overwrite a position that >eliminates a hash move which eliminates an extensions? > >_not_ a good design, IMHO. Ok You say in other words: It is not a good design to make programs use null move pruning. It is not a good design to make programs better. For some reason I prefer to be dependent on move ordering and better. I do not care about instability if it makes my program better. Uri
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