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Subject: Re: Crafty - Forward vs. Backward Analysis

Author: Steve Coladonato

Date: 16:13:52 06/10/02

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Maria,

Yes, I have Chess Tiger (Chess Assistant) and Shredder (Shredder 6).  However, I
have all but gotten rid of Windows and switched over to SCID and Crafty on
Linux.  I still have a couple of old Oracle Power Objects programs to convert to
JDeveloper or Oracle Forms and then it's good-bye Windows and I gain another 10G
of disk for Linux.

Steve

On June 10, 2002 at 11:38:50, maria clara benedicto wrote:

>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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