Author: Dave Gomboc
Date: 17:06:28 08/07/00
Go up one level in this thread
On August 07, 2000 at 05:58:44, Andrew Williams wrote: >On August 06, 2000 at 20:10:49, Vincent Diepeveen wrote: > >>On August 06, 2000 at 19:17:18, Tom Kerrigan wrote: >> >>>On August 06, 2000 at 16:37:24, Vincent Diepeveen wrote: >>> >>>>On August 06, 2000 at 12:45:11, Dan Andersson wrote: >>>> >>>>>Vincent has had this idea of MTD and never managed/bothered to defend it. I >>>>>believe it to be an unsupported opinion. >>>> >>>>No commercial program uses MTD. End of proof man. >>> >>>I thought the MP version of Fritz does. >>> >>>-Tom >> >>I never saw any MP version of Fritz in the shops so far, >>perhaps someone is gonna state soon that DB used MTD too. > >Oddly enough, this seems to be what Hsu says in his IEEE Micro article. >Unfortunately, he doesn't say quite enough to be clear: > > "The search control does not really implement the regular > alpha-beta search algorithm [Ref: Knuth & Moore 1975]. Rather, > it implements a minimum-window alpha-beta search algorithm > [Ref: Pearl 1984]" > >This is a bit ambiguous, because of course PVS could be called a "minimum >window algorithm". But the rest of the paragraph (which is too long to type >here) does seem to suggest that DB was using something more like MTD than >PVS. I don't know if Bob knows for sure (maybe it's in Hsu's book?). Either >way, I'd recommend looking at the article, "IBM's Deep Blue Chess Grandmaster >Chips", Feng-hsiung Hsu, IEEE Micro March-April 1999. The relevant section >is "Search Control" on page 80. > >Having said all that, I think your argument about commercial programs and MTD >is flawed (whether DB used MTD or not). The problem is that MTD is a relatively >new technique, like bitboards. AFAIK, no commercial program uses bitboards >either. I know you don't like that technique, Vincent, but no sane person >would say that the fact that they're not widely used in commercial programs >"proves" that they're no good as an approach to creating chess programs. > >Andrew Judea Pearl's work was the inspiration for mtd() methods, but I agree, it's not conclusive. Dave
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