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Subject: Re: deep blue game 2 analysis finished, question for Dr. Hyatt

Author: Robert Hyatt

Date: 19:53:47 09/13/01

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On September 13, 2001 at 17:26:21, K. Burcham wrote:

>
>
>Question for Dr Hyatt: in the final position, Joel Benjamin said deep blue
> eval was close to +2.00.  shredder5 finds 45...Qe3 in 30 seconds with
>   1500 mhz.  eval starts out at +1.88, with shredder5, and drops quickly.
>in 3 minutes shredder5 eval drops to +1.40. in 15 minutes shredder5 eval
>drops to +1.26. i do not understand how deep blue eval can be +2.00.



Two things.  1.  We have seen several positions where shredder says +5 and
other programs say +2.  There is therefore nothing to say that there are not
also positions where shredder will say +2 and other programs will say +5.  This
fairly small difference in evaluations is hard to speculate on.  IE it is
possible that DB used DT's pawn=1.28, which means a score of +2 is roughly 1.5
pawns ahead.  I don't really know here...





>deep fritz and GT2.0 are similiar in this 45...Qe3 eval. if deep blue
>was so far ahead of these rpograms in kns, it seems in this final position
>that deep blue eval should be somewhat lower than +2.00 for 45...Qe3,
>you would think in this position deep blue could see the drawn position
>  of 45...Qe3. and if you say it could see the draw, then why did Joel
>   say eval was close to +2.00.



It couldn't see the draw.  We already know that the draw requires a search of
60 plies to reach the longest forced drawing position.  I don't think any
program is capable of that in this position.


Don't forget my comment about the value of a pawn.  Some programs use .75,
some use 1.00, and DT even used 1.28.  You can't compare evaluations from
programs that vary the value of a pawn (material score only) that much.

2*.75=1.5, 2*1.28 =2.56.  etc...




>
>
>thanks
>kburcham



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