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Subject: Re: Deeper blue was probably a root processor

Author: Ed Schröder

Date: 12:32:26 07/22/00

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On July 22, 2000 at 14:16:51, Andrew Dados wrote:

>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
>
>What you just said is pretty much confirmation of preprocessing to me:
>'After a queen exchange in the next move often other more accurate tables are
>used []'...
>If it is done in the search - then no score differences should be seen; if it is
>done at root then it is clear preprocessing...
>
>-Andrew-

Yes such ticks are preprocessing. And it helps. But note that in Rebel
only a few things are done this way not more than being < 0.5% of the
total knowledge. That makes Rebel not a root processor and DB neither
which was my reply to header of the subject.

Ed




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