Author: Uri Blass
Date: 14:54:14 01/31/02
Go up one level in this thread
On January 31, 2002 at 16:34:52, Dann Corbit wrote: >On January 31, 2002 at 16:19:51, Uri Blass wrote: > >>On January 31, 2002 at 14:36:04, Dann Corbit wrote: >> >>>On January 31, 2002 at 14:31:38, David Rasmussen wrote: >>> >>>>On January 31, 2002 at 13:13:57, Dann Corbit wrote: >>>> >>>>>On January 31, 2002 at 06:58:28, David Rasmussen wrote: >>>>>[snip] >>>>>>>Just like "ply" means 20 different things to 20 different programmers. Even >>>>>>>"nodes" does not always mean the same thing. >>>>>>> >>>>>> >>>>>>Agree with you on nodes, but ply? Ply is pretty well defined, I think. >>>>> >>>>>For sure it is not. In fact, even when we agree, we disagree. Every single >>>>>chess program will have a tree of a different shape. So even when we count >>>>>plies the same way, the actual search can be incredibly different (with the >>>>>number of nodes visited differing by several orders of magnitude). Compare, for >>>>>instance, Mchess with Goliath. >>>>> >>>>>Junior [for instance] does not count plies the same way as other programs. >>>>> >>>>>Ply is ill defined. In fact, I think it is actually impossible to define it >>>>>accuracy, except in the brute force sense. And absolutely nobody exhausts a ply >>>>>when doing chess games with an engine. >>>>>[snip] >>>> >>>>That is bull. A ply is a half move and that is that. What you are talking about >>>>is: what does it mean when we say a program searches 8 ply? Of course if that is >>>>the question, the answers are as many as there are programs. But in this thread >>>>we are talking about a full width alpha-beta tree (at least, since DB had >>>>singular extensions, which requires extra searches), of some fixed depth search >>>>in a given program (that is, move ordering and evaluation forms the tree). >>> >>>I suggest that you lookup with the CCC search engine the dozens of posts that >>>shot *ME* down when I tried to insist that a ply is a ply is a ply. >>> >>>The thorough and convincing arguements against it showed that I was clearly >>>wrong. >>> >>>As you are clearly, unmistakeably, and totally wrong right now. >> >>He is not wrong if we talk about full width alpha beta. > >Which is the same as saying "If we all wore giant balsa-wood shoes, we could >walk on water." >Nobody wears them, as far as I know. > >There is no chess program on the planet that does that. (Except -- of course -- >for the rankest sort of amateur program). No commercial program but it does not mean that deeper blue did not do it. I agree that plies do not mean the same for top programs but the discussion is about deeper blue and not about the top programs. Thanks to posts of Ed and Andrew It is known that deeper blue searched deep force depth of only 12 plies and the reason that they searched only 12 plies was the fact that they used more extensions than the top program of today. other programs do not use brute force and use less extensions so 12 plies of deeper blue are usually more than 12 plies of other programs. My opinion is that 11-12 plies that were searched by deeper blue may be eqvivalent to 13-14 plies of Crafty. Uri
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