Author: blass uri
Date: 00:57:13 11/11/99
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On November 10, 1999 at 22:15:59, Robert Hyatt wrote: >On November 09, 1999 at 19:41:02, Dann Corbit wrote: > >>On November 09, 1999 at 10:51:00, Ed Schröder wrote: >>[snip] >>>It's indeed more complex than that. Set [Chessknowledge = 500] and NPS >>>will go down, set [Selective Search = 001] and NPS will drop even more. >>> >>>Changing one parameter in Rebel (which isn't available for the user) and >>>NPS will go up with a factor 3-4 which means Rebel would go over 1,000,000 >>>NPS on a fast PC. >>> >>>The bottom line is that NPS (like ply-depth) is pretty meaningless. >>I think that ply depth is an excellent indicator of understanding of the >>position unless the program has bugs. That is to say, if one program finds a >>best move at ply 10, so will the other most of the time. Certainly, if we have >>a complete search (no special pruning) and two programs complete the same ply, >>they will have very similar answers most of the time (given that the eval is >>half-decent or better). >> >>If one program gets two piles deeper all the time, I think it will even beat a >>program with a somewhat better eval. > > > >This isn't always true. IE a null-move program using R=2 will generally search >2 plies deeper than a program that doesn't use null-move. And it will generally >take 2 more plies to see some tactical shots that the R=2 searches 'hide'. And >then there are programs (Deep Blue comes to mind) that not only doesn't use >null move at all, but they do extensions that the rest of us don't consider >because of the expense. IE they reported on "singular extensions". I have now >seen Hsu mention a new form of this they used, which basically says "If one >move is clearly the best, extend a bunch, if two moves are clearly better than >the rest, extend, but not so much..." So their 8 ply search likely will see >things that everybody else's 12-14 ply searches won't see. I am not sure about everybody else because I believe that chessmaster usually does brute force search of only few plies. something like 4/10 is typical to chessmaster and I understand that it says that it looks for 4 plies brute force depth,it looks almost at everything at depth 10 plies and does a lot of extensions(can be many plies of extension) Uri
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