Author: Christophe Theron
Date: 13:00:32 08/08/00
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]"
The reference "Pearl 1984" clearly indicates that they are using PVS/Negascout.
Christophe
>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
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