Author: Amir Ban
Date: 13:03:59 07/22/00
Go up one level in this thread
On July 22, 2000 at 15:32:26, Ed Schröder wrote: >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 I disagree. Even if only a small part is preprocessed, the effect here is huge: half a pawn. DB played 37... Qxf1+ into an even position and woke up a move later into a half-pawn disadvantage. This means that according to its own evaluation Qxf1 is a blunder and would never have been played if not for preprocessing. DB switched from Qe2 (-21) to Qxf1+ (+2) and then learned that it's actually Qxf1+ (-48). So Qe2 was clearly better by DB evaluation. Junior evaluates Qe2 and Qxf1+ as equals. Amir
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