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Subject: Re: Self-test and others rating stuffs...

Author: Robert Hyatt

Date: 14:45:11 01/02/98

Go up one level in this thread

On January 02, 1998 at 17:05:13, Don Dailey wrote:

>On January 02, 1998 at 16:20:29, Amir Ban wrote:
>>On January 02, 1998 at 14:59:02, Don Dailey wrote:
>>>On January 02, 1998 at 14:03:48, Stuart Cracraft wrote:
>>>>Perhaps not directly related but I'll share this anyway...
>>>>My experience in adding knowledge to the evaluation function
>>>>and its relation to test results is that pure tests like
>>>>Win-at-Chess and other tactically-based tests, including
>>>>rating tests that are more tactical (like Kaufman's) suffer for
>>>>more evaluation knowledge but that non-tactical tests may benefit.
>>>>A recent result was that correcting some pawn structure logic
>>>>in a program that was mis-evaluating passed/doubled/isolated
>>>>pawns dropped the Win-at-Chess score by about 2.66% in total
>>>>problems solved but raised the Louguet rating by 45 ELO points.
>>>>At the same time the Louguet result went up 45 points the
>>>>Kaufman result went down 24 points.
>>You were almost certainly looking at random noise. In a 300 position
>>test-suite, I can get the SAME program scoring 3-6 less on its "bad"
>>day. Test suites like Louguet are so small that no real significance
>>should be attributed to any particular result. Understanding the effects
>>of noise is the key to keeping your sanity in this business. Controlling
>>it is a different question.
>>>>This result came by making only these changes:
>>>>  1. correctly evaluate passed pawns based on rank
>>>>     (previously, no passed pawn logic)
>>An important change for endgames, but cerainly not for the WAC suite.
>>>>  2. correctly evaluate doubled pawns
>>>>     (previously, penalized 2 pawns on file, but ignored more than 2)
>>Isn't this totally insignificant ?
>>>>  3. correctly evaluate isolated pawns based on file
>>>>     (previously did not take file into account.)
>>What's the correct evaluation of isolated pawns based on file ?
>He is a thought on the isolated pawn thing.  Like any pawn structure
>thing a good program will have different values depending on file
>and rank.  For instance a backward 'a' pawn is not nearly as serious
>as a backward d or e pawn.
>-- Don

I'm not sure I agree with this.  Generally an isolated pawn on the edge
is not quite as bad as one in the middle, because it can only be
from the front/back and one side, rather than both sides. but I've lost
plenty of games from a weak a pawn.  (weak = isolated, backward, and
so forth)..

I think the file is less important than other things about the pawn...
is the file half-open and does the opponent have rooks to attack down
file?  etc...

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