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Subject: Re: Deeper blue was probably a root processor

Author: Robert Hyatt

Date: 13:13:15 07/22/00

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On July 22, 2000 at 14:11:20, Ed Schröder wrote:

>On July 22, 2000 at 13:28:28, blass uri wrote:
>
>>Deeper blue had a positive evaluation before trading queens.
>>
>>The evaluation of Deeper blue was based on Deeper blue's logfile
>>
>>9(6)  3 T=46  34...Qxf1
>>10(6) 2 T=130 34...Qxf1
>>11(6) 2 T=168 34...Qxf1
>>
>>The evaluation when deeper blue started to ponder (hash guess Rxf1) was
>>
>>7  (4) -30
>>7  (6) -66
>>8  (6) -50
>>9  (6) -50
>>10 (6) -50
>>11 (6) -48
>>
>>Deeper blue lost 0.5 pawn in the evaluation and the only reason that I can
>>explain it is that it is a root processor.
>>
>>I guess that something like this cannot happen to Deep Junior because it is
>>probably more knowledge based program.
>>
>>Uri
>
>The behavior you describe is quite normal. After a queen exchange in the
>next move often other more accurate tables are used which may cause such
>score differences. I do the same in Rebel. That doesn't make the program
>a root processor. A root processor is a program that totally (or to a
>great extend) relies on the evaluation on the root. If you read the IBM
>pages it is said DB has something similar (a short investigation at the
>root). That makes DB no root processor.
>
>Ed


The only root processing they do is to make a decision about which set of
evaluation weights to download to the chess processors.  This decision is
made once at the start of a search.  So there might be a bit of what you
would call root processing, perhaps.  But it isn't what I would consider a
very accurate description.  I have different tables of values I select at
the root.  But all my evaluation work is done at the tips, just like DB
did...



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