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Subject: Re: Crafty - Forward vs. Backward Analysis

Author: maria clara benedicto

Date: 08:38:50 06/10/02

Go up one level in this thread


yes. consistency is kool. looks better than hit-&-miss.

even free-rebel use forward style analysis.

but if you have chess tiger, shredder, why not use it too?

let loose - open mind.

meaning. compare forward-backward analysis of your games.

you get diffrent view about your game. improve your game.

regards

maria

On June 10, 2002 at 10:58:41, Robert Hyatt wrote:

>On June 10, 2002 at 08:30:01, Steve Coladonato wrote:
>
>>Is there any significance in the quality of the analysis that is produced when a
>>program (Crafty) performs its analysis forward, i.e. starting at move 1, through
>>the game vs a program(s) (Chess Tiger, Shredder) that perform analysis backward,
>>i.e. starting at the last move.  >
>
>Here is the "thinking" about going backward:
>
>as you back up thru the game, scores from later searches are stored in the
>hash table and they propagate back up the game as a result, letting the program
>often see some tactical flaw earlier in the game (because it knows about the
>tactical problems that occur later in the game first).
>
>I don't like it.  And here is the "why"...
>
>When you go thru a game in the forward direction, the program will spot any
>tactical oversight its search is capable of finding.  When it complains that
>you made a worse move than necessary, this will be based on its search, and it
>will be repeatable across games.
>
>When you go backward, you hope that the important tree search results stick
>around long enough to be used a few moves back in the game, giving you better
>scores.  But this is based on a lot of serendipity (luck).   If key table
>entries survive, you get better analysis.  If they don't, you don't.  This
>means that the "analysis" by the engine has a strong luck component in how
>accurate it is.
>
>I personally prefer "consistency" to "spotty genius-like" analysis because
>I want the same quality of analysis for each of my games...  It makes it easier
>to understand what the machine sees.
>
>Remember that the computer will produce some analysis at the point in the game
>where it sees the score drop.  Going forward, it will happen at about the
>same "depth" each time.  Going backward, it will vary significantly...



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