Author: Ricardo Gibert
Date: 08:23:35 01/31/02
Go up one level in this thread
On January 31, 2002 at 08:38:31, Uri Blass wrote: >On January 31, 2002 at 08:33:32, Ricardo Gibert wrote: > >>On January 30, 2002 at 12:11:16, Robert Hyatt wrote: >> >>>On January 30, 2002 at 11:00:58, Alexander Kure wrote: >>> >>>>On January 30, 2002 at 10:25:41, Robert Hyatt wrote: >>>> >>>>[..] >>>> >>>>>You can make up all the math you want, but it doesn't prove anything. I >>>>>_know_ that DB's branching factor was roughly 4.0, as was discussed _here_ >>>>>a few years ago after several of us looked carefully at their logs. >>>>> >>>>>to go to depth 18 requires 4^17 as many nodes as searching to one ply. >>>>>4^17 = 2^18, = 262,000 roughly. >>>> >>>>4^17 = 2^34 >>>> >>>>[..] >>>> >>>> >>>>Greetings >>>>Alex >>> >>> >>>You are right. Wasn't thinking clearly at the time, obviously. >>>:) >>> >>>Bob >> >>But at the time, you must have thought you were thinking clearly or you surely >>would not have made the post. This raises the question of, "How do you know you >>are thinking clearly now?" ;-) >> >>Nothing "obvious" about it, yes? >> >>Setting aside my stupid jokes, the serious question now is: "Isn't 2^34 a bit >>too big for Deep Blue?" > >200M nodes/second*180 seconds=36*10^9>2^34 2^34 figure is how many times more nodes must be searched than a 1 ply search (see http://www.icdchess.com/forums/1/message.shtml?210884). If we make the very generous assumption that the BF at the root is only 4 (at least 30 actually. RH assumed 100 for example), then the inequality becomes 3.6E10 < 6.4E10. When you factor in that this assumes iterative deepening is not employed, then it is not even close. I will admit that it is closer than I originally thought, however. > >2^34 nodes is not too big for a machine that can calculate 200M nodes per >second. > >Uri
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