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Subject: Re: Some facts about Deep Thought / Deep Blue

Author: Robert Hyatt

Date: 07:32:58 08/30/01

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On August 30, 2001 at 05:43:41, Uri Blass wrote:

>On August 30, 2001 at 05:28:14, Gian-Carlo Pascutto wrote:
>
>>On August 29, 2001 at 23:10:56, Robert Hyatt wrote:
>>
>>>The "weights" don't always reveal what they stand for.  I've had the DT
>>>code for at least 2 years.  It isn't new.  But I can give you the weights I
>>>use in Crafty and they don't tell you _what_ I am actually doing with them,
>>>only the numbers I am using.  Their bishop of opposite color + pawn ending
>>>evaluation was _very_ good.  Once Hsu explained it to me at an ACM event.
>>>You won't find that explanation of how it works in the stuff you reference.
>>>
>>>Which is a shame, actually.  There's a lot in the thing that we won't ever
>>>know in great detail.
>>
>>The code includes the full eval itself. You can check it out and see
>>how they did kingsafety, bad bishops, passed and blocked pawns, etc...
>>
>>The tuner has that code because it is useless without it. You can't
>>tune an eval if you haven't got any.
>>
>>What I don't see is the endgame stuff you talk about. I see two possible
>>explanations:
>>
>>a) they thought it was so great that it shouldnt leak out and carefully
>>removed all references from it from the tuner
>>
>>b) they simply didnt _have_ it yet at the 1988 US Open. Perhaps it was
>>added afterwards in DT, DT2 or DB, and you are confused about when they
>>talked about it to you or implemented it.
>>
>>Make your pick.
>>
>>I think what the code shows is that in the 1988 US Open, Deep Thought
>>did not have great sophisticated evaluation. An ok one yes, but it's
>>certainly been surpassed by the micros in the meantime.
>>
>>Which doesn't mean anything about the evaluation of DT after 1988 or
>>of its succesors, but I find it awkward to be making much fuss about
>>DT's supposed evaluation if you can _look_ at it and see what they
>>did and did not do.
>>
>>--
>>GCP
>
>I remember that  I read that Deep thought lost a match 2.5-1.5 against bent
>larsen(I am not sure if it was in 1992 or 1993) and I read that deep thought
>could probably win by trading queens because the opposite color bishop endgame
>when deep thought has 2 passed pawns is not a draw.
>
>Deep thought did not know about it at that time and I remember that they
>admitted that they need good chess players with knowledge about chess to help
>them.
>
>Uri


That sounds like the event that triggered their adding the new knowledge into
the program.  But I am not certain.



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