Author: Ricardo Gibert
Date: 04:23:24 05/30/05
Go up one level in this thread
On May 30, 2005 at 06:21:14, Pallav Nawani wrote: >On May 30, 2005 at 02:02:49, Amir wrote: > >>Deep Blue could calculate 200 million moves per second. According to what I have >>read, Hydra calculates 40 million moves per second. How then is Hydra sees >>deeper or is faster than Deep Blue, as is claimed by the authors?? > >According to the logs that I saw, deep blue was searching 12 plies deep in the >K-DB match. My program can match that depth on a 1.1Ghz PC. This is because of >search techniques that were not used in deep blue. Eg: Null move, Rebel style >reductions, aggressive pruning. Hydra is obviously using such search techniques, >and given its higher processing power, it will easily outsearch Deep Blue. In >fact, in Shredder-Hydra match, shredder was searching to 16 ply (I think, but I >could be wrong) which was almost the same as Hydra (Again, not sure). > >Also, Deep Blue was using Singular Extensions, which increases the number of >nodes required in search. But which also reduces EBF. You should have left out this paragraph. > >Also note that 9 plies of program 1 are not the same as 9 plies of program 2. >These programs may be using different search techniques/extensions etc, and >therefore on basis of plies searched you cannot guess the relative strength of >programs. For instance, singular extensions are reputed to increase tactical >strength quite a bit, but they may decrease the depth of search. > >Pallav I better though still imperfect comparison uses: effective_depth = log(nodes)/log(EBF) If given 2 programs where one reports a lower depth, because it does a lot of extentions and another that reports a higher depth, because it does a lot of pruning, but they otherwise generate the same search tree, then the above will return the same effective_depth.
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