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Subject: Re: Criteria for Good Test Positions = ?

Author: Bob Durrett

Date: 17:04:10 12/10/02

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On December 10, 2002 at 15:47:19, Mike S. wrote:

>On December 09, 2002 at 19:37:17, Bob Durrett wrote:

<snip>  [Hope I didn't snip too much.  : (  ]

>>My thinking now is that it may be good to let a chess engine analyze the entire
>>GM game.  The average analysis time per move could be set to approximate
>>tournament time controls.  The key to success of this method would be to use
>>extremely high quality games, with equally extremely high quality GM analyses.
>>
>>Then the computer's understanding of the positions of the game could be
>>compared to the GM analyses.
>
>You could try that using Fritz' "Full Analysis" feature or a similar feature of
>another program. If there is a threshold value (like in Fritz) to be set, which
>controls how big the difference of the evaluations has to be to produce a
>commentary variant, then I'm afraid it would have to be set to a small value for
>positional things. I would expect that positional observations are - most often
>- about much smaller eval differences that i.e. a blunder which looses a pawn or
>the like.

Wouldn't that depend on how the chess engine performed its evaluations?  If the
chess engine only does tactical evaluations, then that would always be true.
But cannot someone create position evaluation software that examines positional
as well as tactical features of the position?  I actually believe that modern
chess engines do that already.

Anyway, it is interesting that you say that.  I believe that was the essence of
what Rolf was saying too, before he became frustrated and ran away.  As I
understood it, he saw "positional" positions as being those that a chess engine
would "think" to be equal and quiet.  Any tactics would be beyond the chess
engine's horizon, for any reasonable analysis time.

The idea that "positional" positions could not yield high position evaluation
scores is something that should be examined closely.  It is not clear to me that
it is impossible or highly improbable that chess engines would assign
significant values to some "positional" positions.  [I guess Uri would say I
should give a position to illustrate this point, but I cannot think of one.]

There may be two difficulties here:

(1)  Impossibility of producing a "positional" position which is completely
non-tactical, and

(2)  A possible problem with uncertainty:  Position evaluation software may not
always be able to produce an answer to "Which is the best move?" with *absolute*
certainty.  Maybe "positional" positions necessarily contain too much
uncertainty. [?]  If significant searching is required to determine the best
move, then my intuition tells me we are back to square one, but that could be
wrong.

Forced move sequences are normally thought of as tactical, but I can see the
possibility of "forced" move sequences of positional moves too. [The only truly
forcing sequence is a sequence of checks or mate threats.]


>In result of that, you will get comments and variants for very many
>moves, and again, you would have to analyze what really makes sense for the
>intended purpose...
>
>I usually start all analysis with a non-automatic :o) manual browsing through
>the game, more or less quick, where I'd already spot things like above (also
>some less simple one's :o) That can be more effective IMO than let run long
>time-consuming automatic analysis proceedures, whereafter one has to analyse
>manually anyway again, to choose the really interesting things from all the
>stuff the engine has produced.

Yes, that's what I do whenever beginning analysis of a new game.  I use a series
of successively deeper looks.  In my personal games, identifying the blunders is
usually sufficient, but when analyzing GM games, that's a different story!  : )

Bob D.

>
>Regards,
>M.Scheidl



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