Computer Chess Club Archives




Subject: Re: Artificial Intelligence in Computer Chess

Author: Vasik Rajlich

Date: 02:19:30 04/01/04

Go up one level in this thread

On March 30, 2004 at 17:20:03, Jay Scott wrote:

>On March 29, 2004 at 19:03:22, Uri Blass wrote:
>>On March 29, 2004 at 18:52:52, Jay Scott wrote:
>>>Chess programmers, I've found, are remarkably resistant to changing how they do
>>>certain traditional things. For example, every time I propose calibrating
>>>evaluation not in millipawns but by some standard with a sounder theoretical
>>>motivation, I'm shouted down by everyone who does not ignore me. I don't
>>>understand that.
>>I do not know what you mean but if you mean to evaluation in terms of expected
>>result then
>>I am not against evaluation not by pawns but by expected result.
>Yes, that's an example.
>>The problem is that it is not easy for human to think about defining the
>>evaluation when it is in terms of expected result.
>Hmm, some humans, no doubt. Not the theoretically-minded, who are apparently a
>small minority.  But especially not when the evaluation is tuned by machine
>learning, or even by a human using formal methods (imagine a test suite that
>estimates how accurate each factor in the evaluator is). Then a sound
>theoretical basis behind it all can help us come up with methods that are more
>powerful. This is especially true when it comes to interactions between
>evaluation features.
>Most chess programmers, apparently, find it easier or more satisfying to eyeball
>their results and tune by the seat of the pants.
>  Jay


I would love to hear something a little more concrete.

My own engine (Rybka) is too young to tune yet. I need to capture the right
terms first. You don't want to just tune for example a passed pawn weight -
first you need to discriminate the different types of passed pawns, then as a
last step you determine the weights.

However, I would be very curious to see which of my terms are doing anything.

I do some tests disabling various terms, to see the magnitude of the differences
in scores. However, this doesn't really say anything about how beneficial they


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