Author: Uri Blass
Date: 04:43:40 10/11/02
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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. > >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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