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Subject: Re: Problem: knowing nothing about a position = score 0??

Author: José Carlos

Date: 15:09:54 10/28/02

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On October 28, 2002 at 14:54:58, Aaron Tay wrote:

>On October 27, 2002 at 18:41:22, José Carlos wrote:
>
>>On October 27, 2002 at 18:25:32, Ingo Lindam wrote:
>>
>>>On October 27, 2002 at 18:01:30, José Carlos wrote:
>>>
>>>>  There's a difference between:
>>>>  a) my knowledge doesn't fit the position (ie no open lines where I have a
>>>>bonus for open lines).
>>>>  b) the sum of weights is zero (I have one open line and my opponent has one
>>>>open line).
>>>>
>>>>  In the first case, you're right that zero eval is misleading and dangerous.
>>>>  In the second, the position is probably balanced (if this applies to many
>>>>parameters, of course, not just one), so the zero is correct.
>>>
>>>
>>>You are right about that difference... but I want to give you a realistic
>>>example for the programm evaluate near 0 for the few things he can
>>>evaluate...and another 0 for all the things it doesn't know anything about.
>>>My problem still isn't solved. You wouldn't play towards a position you just
>>>know it is ballanced in the aspect of open files, but in all the other aspects
>>>you can't judge it at all, would you?
>>
>>  I know what you mean, but I'm afraid I wasn't clear myself.
>>  Suppose I'm a program who has 50 eval terms (open lines, knights in the center
>>of the board, doubled pawns, pawn protection around the king...).
>>  I look for those 50 patterns on the board:
>>  a) I find them all there. The final sum is near zero. In this case, I can only
>>conclude that the position is balanced.
>>  b) I only find 10 and they seem to be balanced. In this case, your idea is
>>totally correct: I might want to go to that position thinking it's drawn, but I
>>would be going into an unknown (for me) position.
>
>Why the cutoff at 10?


  Just an example :)

  José C.


>>  If b happens, the program should be able to assess a negative score for
>>itself, but: b happens very seldom, if ever; if a happens it is possible that
>>the program is simply not understanding the position, but that might be true no
>>matter what the score is.
>
>It also seems to me that it might not understand the position, but in fact might
>even be winning in a few moves! It would be sheer irony, for the program to
>avoid those positions.
>
>
>>  So my point is that your idea is correct, but extremely difficult to detect.
>
>Maybe it can be studied, by logging positions where such occurances happen, and
>study the positions after and see whether it is true, the theory that such
>positions are bad.
>
>>  José C.



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