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Subject: Re: Static evaluation after sac, how about asymmetry?

Author: Vincent Diepeveen

Date: 18:31:09 12/03/99

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On December 03, 1999 at 18:10:03, Will Singleton wrote:

>On December 03, 1999 at 08:49:19, Andrew Williams wrote:
>>Over the last few days, I have been fascinated by the discussions on CCC
>>about positional sacrifices. Some of the discussion has centred on the value
>>assigned to the attack that is obtained after the sacrifice and I was wondering
>>how other programs evaluated the position after Hossa's sac:
>>r3q1k1/ppp1rp2/2n1b2Q/8/2P5/3B4/PPP2RPP/5RK1 b - - 0 2
>>This is after 1. Bxh6 gxh6 2. Qxh6 from the original position posted by
>>Peter McKenzie. PostModernist's static evaluation of the position is presented
>>below. Essentially, it thinks that White is winning by 0.71. The ATTACKTOTAL
>>score is generated by analyzing the squares around the King to see how many of
>>them are attacked and what sorts of pieces are attacking them. Please note that
>>not all the factors that contribute to PM's score are included in the output
>>Could other programmers post similar information? I believe that even an
>>overall static evaluation would be interesting.
>>Andrew Williams
>>BLACK to move
>>MATERIAL -137 (Positive means WHITE has more material) W:19086 B:19223
>>Game stage M
>>Actual moves played: 1 (halfMoves=1)
>>Fifty move counter: 0
>>r=547      #       #       #    q=1040     #    k=15939    #
>>o=103   o=106   o=103      #    r=565   o=94       #       #
>>   #       #    n=346      #    b=346      #       #    Q=1022
>>   #       #       #       #       #       #       #       #
>>   #       #    P=101      #       #       #       #       #
>>   #       #       #    B=344      #       #       #       #
>>P=103   P=103   P=98       #       #    R=553   P=103   P=115
>>   #       #       #       #       #    R=555   K=15993    #
>>HCW=1   HCB=1
>>cannotCW=1      cannotCB=1
>>CCRW=0  CCRB=0
>>Piece Bonuses White=4   Piece Bonuses Black=-34
>>EVALUATION : 71 (positive means WHITE is winning)
>For Amateur:
>r3q1k1/ppp1rp2/2n1b2Q/8/2P5/3B4/PPP2RPP/5RK1 b - -
>Using a static eval, I get different results if it is White or Black doing the
>evaluating.  I guess this is a result of my asymmetrical king-safety.
>White says +0.73, Black says +1.29 (+ is good for white).  Does anyone else do
>this asymetrically?

Except for an experiment giving the side to move a bonus to some extend
i've never been assymmetric. When I threw out this bonus too, then
diep improved a lot in level.

Logical one would say a bonus for having the side to move is good,
but it never worked for DIEP.

Never figured out why. Did i have a bug?

Apart from this discussion, from which i don't know whether it's good to have,
being assymetric becasue white might be a human and black a computer,
i am against using an assymmetric evaluation function for that.

Contempt factor should already prevent getting a draw namely. No need
to underestimate the opponent somehow or favour open position for the
computer a lot more, though at the icc server this means obviously
you lose a lot of points to draws in closed positions.

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