Author: Robert Hyatt
Date: 18:57:34 10/11/02
Go up one level in this thread
On October 11, 2002 at 17:51:27, Omid David wrote: >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. However, they have _never_ said they didn't use forward pruning. They have only said "we don't use null-move for forward pruning" and nothing else. And they have slowly leaked details. But they pretty much had to since I had gone over their log files and discovered that theyt had a _very_ good branching factor, too good for pure alpha/beta alone... > > > >> >> >> >>> >>>> >>>>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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