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Subject: Re: Assymetry & Bonus in Static Eval? Black apples and white pears?

Author: Dave Gomboc

Date: 17:40:02 12/05/99

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On December 05, 1999 at 19:50:15, Vincent Diepeveen wrote:

>On December 04, 1999 at 22:09:41, Eelco de Groot wrote:
>
>>Steve:
>>Do I understand correctly--for each static evaluation of a single position (leaf
>>node, I guess), the program evaluates based on material and positional factors
>>without regard to which side is on the move?  Then, some programmers like to add
>>a bonus for the side to move?
>>
>>Vincent:
>>It's an heuristic that's true in 99% of the positions that my program
>>searches obviously.
>>
>>If a position is bad then usual programs nullmove. If a program nullmoves
>>then the other side has the move so gets the bonus.
>>
>>So the sword cuts on 2 sides. Where you can nullmove normally to prevent
>>getting into a worse position, you now suddenly cannot as your opponent
>>gets the bonus instead of you.
>>
>>
>>Me:
>>Now I have never done any chessprogramming, but it seems fairly straightforward
>>to say that you only need to think about such a bonus if you are comparing
>>positions with White to move and positions with Black to move, right?
>>Intuitively something tells me that is not without dangers. Isn't that a lot
>>like comparing apples and pears? Wouldn't it be a lot better if only even plies
>>were evaluated if possible? A recent discussion between Ed and Christophe about
>>the early Rebel comes to mind... That way you can focus much more on plans ,
>>weaknesses, etc. of your own. You could save a lot of time time that way! Of
>>course you can't ignore the opponent regardless, but you could use a different
>>evaluation for uneven plies, looking more for tactical threats for instance?
>>That would be relatively safe to do as long as you have the initiative..
>>
>>If this isn't possible because of nullmove, isn't that a weakness of normal
>>nullmove? Vincent I understand you are working on something you call double
>>nullmove and that you are going to publish in ICCA journal about it. Has this
>>anything to do with these even/uneven effects. Has double nullmove replaced the
>>bonus in Diep? I must confess nullmove is hardly my expertise, but maybe others
>>can follow better if you have anything to say about this.
>>
>>Thanks for any comments, by anybody
>
>Having a passed pawn can be seen as a risky bonus too.
>It might be hung!
>

It might be well-hung!

;-)

Dave



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