Computer Chess Club Archives




Subject: Re: likelihood instead of pawnunits? + chess knowledge

Author: Vincent Diepeveen

Date: 11:34:58 10/25/02

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On October 25, 2002 at 12:39:38, Ingo Lindam wrote:

Seemingly your idea is a good one, but in fact chess engines
do this.

If you have a set of probabilities say you use 2 criteria.

Now for move P1 you get back:
   A  0.75
   B  1.00

Now for move P2 you get back:
   A  0.60
   B  1.20

*somewhere* in the program you must have a function that's
deciding which is better. P1 or P2.

In short most likely you convert with a formula P1 to
a value V1 and P2 to a value V2.

Then you compare V1 with V2.

Chess engines already do that. Their evaluation function already
combines (A,B) to a V'.

Then you just give back a single value V1 or V2.

So in essence your thing is already getting done in the evaluation
function of a program.

You just make it yourself more difficult when you use 2 or 3 values.

Best regards,

>I repost my former post under this new title just hoping to encourage
>more people to join the discussion:
>I am new at the Computer-Chess Club and would like to discuss some
>suggestions for (a new generation of) chess knowledge using (and
>generating?) chess engines. During my time at the university and at my
>first job after making my exams in computer science I was involved in
>statistical speech/pattern recognition and machine translation. That
>might atleast a reason for some of my ideas.
>I am not sure whether these suggestions have never been made or just
>named to be impossible to implement. (I am sure they are not.)
>I would really like to see the computers measure a position rather in a
>set of probabilities e.g. (P+,P=), where
>P+ = Probability in the position to evaluate white/player to move will
>win and
>P= = Probability that position will end in a draw
>P- = Probability in the position to evaluate white/player to move will
>with P+ + P= + P- = 1
>(also a confidation measure about the Probabilities might be useful)
>Ofcourse out of the set of probabilities a single measure could obtained
>to be optimization criteria in an search algorithm. A simple one would
>be P+ + 1/2P=, but also different formulas considering strength of
>opponent, standing of the match or just an increasing influence of P=
>when position is weak might be interesting.
>Even more important seems to me to demysticize terms like "chess
>knowledge", "experience", "plans", "positional criteria".
>There is such a huge amount of chess games and analysis in a computer
>readable/usable format and what else should be a source of chess
>knowledge than games and results? Yes, there are books and ideas of
>great human chess thinkers as Nimzowitsch. But also his ideas are
>experiences from his own analysis and games and should also be
>verifyable by modern pratical chess. And where not, they might be no
>longer of any use.
>A chess engine that is able to calculate 3 Million positions per second
>should have no problems with dealing with less than 2 Million. As more
>as a lot of conclusions out of the "experience" of 2 Million chess games
>may be drawn rather in preperation of a match than during a game.
>"Positional pattern" (another mysticized term reserved for human beings
>especially GMs) may easily formulated and efficiently retrieved on the
>basis of low level chess position items and clusters of those. Computer
>scientists may argue that there is a too huge amount of possible
>patterns. But a chess engine as well as a GM (not less a normal human
>chess player) should first of all be interested in patterns that often
>apear in practical chess.
>I expect that a CD (or DVD) full of positional chess patterns drawn out
>of a suitable number and choice of chess games (out of a permanently
>growing number) will have a much greater effect on the play and results
>of a chess knowledge using chess engine than 4 or 5  pieces tablebases
>have nowadays on the results of tablebases using chess engines.
>This suggestions or ideas or statements are no critisism of the current
>methods of chess engines. I have great respect of the ability of chess
>engines like ... (we know them all and I don't dare to bring them in an
>order or to leave a talented engine out).
>I just wonder if my suggestion or questions may cause a fruitful

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