Author: Robert Hyatt
Date: 05:09:47 03/03/00
Go up one level in this thread
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".
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