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Subject: Re: DEEP BLUES AVERAGE PLY?

Author: Gian-Carlo Pascutto

Date: 02:31:40 08/22/02

Go up one level in this thread


On August 21, 2002 at 22:35:53, Robert Hyatt wrote:

>On August 21, 2002 at 14:51:17, Gian-Carlo Pascutto wrote:
>
>>On August 21, 2002 at 14:44:37, Robert Hyatt wrote:
>>
>>>>Please look at page 5 very carefully 12.2 ply it says.
>>>
>>>Yes.  And take the logs and add up the _first_ number from each iteration
>>>and divide by N.  Guess what you get?  12.2...
>>>
>>>Which was the software part of their search.
>>
>>They certainly don't say the last.
>>
>>A bit further, you can see that a nominal depth of 12 compromised 8 ply
>>nominal in software. Add 4-5 hardware ply and you get 12-13 ply.
>>
>>8 ply in software, plus hardware plies. Not 12 ply in software plus
>>hardware plies.
>>
>>The paper is pretty conclusive that they were not searching 18 ply
>>nominally, but only 12 ply. They even literally wrote it.
>>
>>--
>>GCP
>
>
>It doesn't read like what the team said, that is for sure.  But there are two
>key pieces of data that I _personally_ know to be true:
>
>(1) deep thought searched 10-11 plies in 1989 at the WCCC in Alberta.  It
>continued to search that deep thru the 1994 ACM event in Cape May, New Jersey.
>I was there.  I watched their monitor as we sat around the table watching their
>games.  So there is absolutely no doubt about that 10-11 ply number as I _know_
>what was happening in those games.
>
>(2) deep blue was claimed to be 100X faster.  That should turn into 4-5 plies
>at their EBF as shown in the logs...
>
>More than that I won't speculate on.  But Cray Blitz was searching 9-10 plies
>at 400K nodes per second, and I _know_ DT was out-searching us at _least_ a
>ply, plus their singular extensions that we were not using in 1989.

I think Uri already sufficiently addressed this question above. Loss of
efficiency, more extensions, and the bad branching factor all contribute to
a minimal gain.

--
GCP



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