Author: Ed Schröder
Date: 23:46:42 04/16/99
Go up one level in this thread
>Posted by Dave Gomboc on April 15, 1999 at 18:29:11: > >In Reply to: Re: The best program of all the times posted by Milton Zucker >on April 15, 1999 at 12:35:57: > >On April 15, 1999 at 12:35:57, Milton Zucker wrote: > >> >>On April 15, 1999 at 09:45:53, Bruce Moreland wrote: >> >>> >>>On April 15, 1999 at 09:34:12, Christophe Theron wrote: >>> >>>>On April 15, 1999 at 09:27:03, Bruce Moreland wrote: >>> >>>>>What is "knowledge based" ? >>>>> >>>>>bruce >>>> >>>>Good remark, Bruce. Here is another one that has no idea of what he is >talking >>>>about. >>> >>>It's an interesting term and I'd like to explore its meaning. I am not >trying >>>to blast anyone. >>> >>>The programs that have this term applied to them are either extremely weak >>>ancient research programs, or very strong commercial programs that nobody >knows >>>anything about. >>> >>>bruce >> >>I will propose a naive definition of a "knowledge-based" chess program, >which I >>invite others to knock down. If two programs A and B have the same >rating, the >>slower program that searches less ply per unit of time is the more "knowledge >>based" in the sense that it plays at the same strength as the faster program >>without seeing the longer term tactical consequences of its move. >Presumably its >>decisions are based on more positional knowledge and less on tactical >>consequences. >>...Milton... > >Alright, here's the truck to knock it down with. :) > >The proposal measures the amount of knowledge in software by search depth. >This >has some intuitive appeal, the logic behind it being that programs that "know >more" will take longer at each node, so they will search less deep. >Unfortunately, there are several difficulties with the proposal: > >1) Search depth is not uniform throughout a search tree. >2) Programs search differently-shaped trees, so their search depths are not >(usefully) directly comparable. >3) What is considered "knowledge" is left unclear. Does this include measures >such as futility pruning -- the understanding that one's position is so good >that there is no need to finish expanding the last couple of ply here? This >"knowledge" increases the speed of your search. >4) The purpose of chess-specific terms in the evaluation is to guide the >search. > This has no more claim to knowledge than non-chess-specific features that >guide >the search. A hash table has nothing to do with chess, but it does more to >guide the iteratively deepening search than any chess-specific term. >5) Software that searches less ply per time unit may be doing so because they >are extending certain continuations further. So, they might well >understand the >long-term tactical consequences of a move even though their reported depth is >shallow relative to some other chess software. >6) What constitutes a "node" for reporting purposes varies from program to >program. Therefore, node count is not an acceptable substitute for search >depth >as a measurement of knowledge. > >I could go on, but the point has (I hope) been made. No doubt, a correlation >between search depth and search effort exists, but this relationship is >individual to within a program, and should not be misleadingly generalized. > >With regards to the state of the art in computer chess today, "Knowledge-based" >is a marketing buzzword, nothing more. IMO, M-Chess, Hiarcs, Rebel, >CSTal2, and any other mainstream commercial chess product have about as >much claim to "knowledge-based" as a hole in the ground. > >Dave This issue is spelled out on my pages at: http://www.rebel.nl/ches2010.htm Special attention to the Chris Whittington point of view, it's a beauty. There is no marketing involved just my point of view about the current state of art of computer chess. Then have a look at the POLL results as they speak for themselves. Ed Schroder
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