Author: Uri Blass
Date: 08:05:50 10/16/02
Go up one level in this thread
On October 16, 2002 at 09:40:21, Jeremiah Penery wrote: >On October 16, 2002 at 07:31:01, Vincent Diepeveen wrote: > >>On October 15, 2002 at 13:31:07, James Swafford wrote: >> >>There is 2 things >> >> a) theoretic branching factor without nullmove >> >>that's true for the last so many plies of deep blue and >>the theoretic truth. >> >> b) branching factor with hashtable. >> >>You will see that deep blue is somewhere, like all software programs >>in the middle of this. >> >>126 mln nodes a second. And it got like 12 ply with a bit more >>than 3 minutes. >> >>that's like total branching factor = 12th root from >>126 mln * 180 seconds = 6.0 > >If you mean (180*126m)^(1/12), that equals 7.294. > >>So the real overall b.f. which was achieved was 6.0 >> >>that's lower than the theoretic branching factor of sqrt(40^18) > >If a decent program didn't have a lower number than the 'theoretic branching >factor...' I'd be very surprised. I believe that it is possible to get a good program with branching factor of 6 and a lot of extensions. I see no contradiction plies do not have to be eqvivalent. > >BUT, if you insist on this number, and you think they only got 12 plies, they >need to search 4096000000 nodes for 12 plies. They can accomplish that in 32.5 >seconds with 126M n/s. 12.2 plies takes 47 seconds. In 180 seconds, they can >do 12.93 plies, in fact. sqrt(40) is a branching factor of 6.32. With a >branching factor of 6, they can reach 13.3 plies in 180 seconds based upon your >formula. No You forget that there is also a constant. If the number of nodes to get depth n is a*6.32^n I see no problem. Uri
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