Author: Dave Gomboc
Date: 18:22:02 03/03/00
Go up one level in this thread
On March 03, 2000 at 17:16:04, Robert Hyatt wrote: >On March 03, 2000 at 15:18:09, Dave Gomboc wrote: > >>On March 03, 2000 at 08:09:47, Robert Hyatt wrote: >> >>>On March 03, 2000 at 03:44:48, Dave Gomboc wrote: >>> >>>>On March 02, 2000 at 18:26:09, Robert Hyatt wrote: >>>> >>>>>On March 02, 2000 at 01:42:43, Ed Schröder wrote: >>>>> >>>>>>On March 01, 2000 at 20:52:52, Jonathan Lee wrote: >>>>>> >>>>>>>Thanks, Pete on IBM's logic on their selling of chess software. If their >>>>>>>software was awesome, they already would have a large share against the top >>>>>>>guns. >>>>>>> >>>>>>>Someday said every 18 months the hardware doubles in speed. >>>>>>>Someone else said IBM's hardware "DB" is 1000 times faster than the 500MHZ PIII. >>>>>>>In the year 2015, (what a bold prediction) PC's will be as fast as Deep Blue. >>>>>>>Do the math: >>>>>>>2 ^ 10 = 1024 (twice the speed 10 times equals about 1000 times faster) >>>>>>> >>>>>>>18 * 10 = 180 (18 months multiplied by ten times equals 180 months) >>>>>>> >>>>>>>180 months equals 15 years >>>>>>> >>>>>>>2000 + 15 = 2015 (We are now in the year 2000; add 15 years and you will get >>>>>>>2015) >>>>>> >>>>>>What about today? >>>>>> >>>>>>Nowadays programs hit a deeper ply depth than DB. See the log files >>>>>>on the IBM site. >>>>>> >>>>>>Ed >>>>> >>>>> >>>>>No... you are mis-reading the logs. When you see depth=10/5, that means >>>>>10 ply (full width + extensions) in the software, another 5 plies + everything >>>>>but singular extensions in the chess engine. When you look at those numbers, >>>>>we are getting crushed in search depth. 10(5) means 15 plies full-width, no >>>>>null-move or anything, + their extensions. >>>>> >>>>>This was covered when we were discussing the DB logs. I confirmed this >>>>>point with two different DB team members to be sure we were understanding the >>>>>(n) number correctly. Looking at the logs, the hardware searches 4-6 plies >>>>>depending on the base software search depth. When you see 11(6) that is a >>>>>full-width 17 ply search, which is awesome. >>>> >>>>Double-check that. 11(6): 17-ply search, yes. _full-width_ 17-ply search, I >>>>don't think so. The top of the software search is full-width, the bottom of the >>>>software search is selective, and the hardware search is full-width again. At >>>>least, that is my understanding. The interesting question is how many of the 11 >>>>in software were full-width... and my recollection is that the answer is not 11. >>>> >>>>Dave >>> >>> >>>There is _no_ selective search in DB. They do "selective extensions" in the >>>software, but _every_ move is searched to at least the depth given. IE if you >>>see 11(6), then *every* move at the root is searched to at _least_ 17 plies >>>deep, not counting the capture search. And most are searched deeper due to the >>>extensions. >>> >>>_None_ are searched to less than that depth. DB _never_ had any sort of forward >>>pruning in the normal search, although it did have a sort of futility cutoff in >>>the capture search only. >>> >>>This is all well-documented. Hsu didn't believe in selectivity at all when >>>applied to pruning. >>> >>>The answer to your question _is_ "11". >> >>It's well-documented for DT. Where is it well-documented for DB? I know Hsu >>didn't like pruning, but by itself that doesn't mean that they didn't do any in >>DB. Does he say so in his book? >> >>My recollection of a conversation with a member of the DB team in 1997 is that >>there was some selectivity going on in the software search, in the manner that I >>described above. >> >>Dave > > >All I can say is what I have been told, which is that "the only selectivity >we do is in the extensions, _not_ in forward pruning." In his book (or in >something he posted somewhere, maybe the IEEE article) he mentioned that he >would like to try something selective (like null-move) in his _next_ chip, >when he was talking about doing one. That suggests to me that he isn't in >the current DB... Okay, but remember that I did agree that the _chip_'s search was full-width. ;-) Dave
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