Author: Omid David
Date: 14:51:27 10/11/02
Go up one level in this thread
On October 11, 2002 at 11:51:13, Robert Hyatt wrote: >On October 11, 2002 at 07:43:40, Uri Blass wrote: > >>On October 11, 2002 at 07:12:34, Vincent Diepeveen wrote: >> >>>On October 11, 2002 at 04:08:49, Uri Blass wrote: >>> >>>Isn't his article clear enough yet? >> >>Bob Hyatt still claims that it was 12 plies software and 6 plies hardware >>so I prefer to hear an answer directly from Hsu. > >I agree. But _I_ don't claiam _anything_ except that members of the DB team >specifically told me that 12(6) means 12 plies in hardware, 6 in software. I >even posted the excerpt from the email that specifically said this... > >That is _all_ I have said about it... > No matter what they say, even under extreme theoretical conditions it is *impossible* to search 18 plies of brute force in chess, without any type of forward pruning whatsoever, and no hash tables. > > > >> >>> >>>reporting a 12.2 average search depth fullwidth. >>>I guess you never searched with a decent program fullwidth >>>with extensions. If you did, you would understand that >>>getting 12.2 ply fullwidth with loads of extensions is already nearly >>>impossible. Every extended line is searched to the full depth, >>>no pruning happens! >> >>I agree that 12.2 plies with a lot of extensions and no pruning is impossible >>for normal programs and also is impossible for deep blue in case that >>there were real 6 more plies in the hardware. >> >>The only case when it may be possible is if the 6 more plies in the hardware are >>real selective search and it means more pruning than null move with R=3 and in >>this case the 6 plies in the hardware may be eqvivalent to only 2 plies in >>software because of big probability to miss things. >> >>> >>>The interesting 2 questions are >>> a) did DB use 'no-progress pruning' in SOFTWARE (we know >>> already it used it in hardware). >> >>They explained in the article that they did not want to take risks of missing >>something in the first plies so it is clear that they did no pruning in the >>first 12 plies. >> >>If they did some pruning in the software it is clearly after it. >> >>I do not know what is exactly no progress pruning. >>Is there a difference between it and null move pruning? >> >>Is no progress pruning more aggresive than null move pruning? >> >>Uri
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