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Subject: Re: Writing a meta-language to describe eval function

Author: Matthew White

Date: 11:42:36 07/02/03

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On July 02, 2003 at 14:25:13, Andrei Fortuna wrote:

>On July 02, 2003 at 14:07:36, Matthew White wrote:
>
>>For example, I once heard a lecture stating that in the opening, a pawn is worth
>>three tempi, meaning that if you can get a three developing move advantage on
>>your opponent, then a gambit is generally okay. It would seem, then, that in an
>>eval, a program could assign a value of 0 for a minus one pawn, plus three tempi
>>situation (absent any other contributing factors). However, if you only have a
>>two tempi and you give the opponent a pawn, does that mean you are -0.33? I
>>don't think that the rule is so hard-and fast... A one tempo advantage is VERY
>>different than a three tempo advantage. An exchange can often be used to regain
>>one tempo, but regaining three tempi requires considerably more work. So is it
>>fair to say that each tempo is worth the same amount? I don't think so. Just
>>something to think about, I hope that all made sense.
>
>I don't think tempi have much use in an eval function.  IMHO they look a bit
>artificial and anyway if you are ahead 1-2-3 tempi then your program will have
>to find a way to transform those tempi into another type of advantage in a
>number of plies.
>
>Andrei

How do you get a program to develop its pieces if you ignore time? Yes,
piece-square tables are helpful, but how do you keep a program from chasing a
piece that it thinks it can exchange, but which will result in letting the
opponent develop his pieces comfortably and start an attack? I realize that we
use opening books specifically to avoid having to think about these issues, but
sometimes when opening books end early, I have seen engines un-develop a piece
that the book just finished developing!

Matt



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