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Subject: Re: MTD is a big disaster

Author: Dan Homan

Date: 08:25:07 07/20/99

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On July 20, 1999 at 08:52:18, Vincent Diepeveen wrote:

>Let's however write down some facts why my prog is unhappy with MTD.
>It's up to others to generalize it to their progs:
>  - the huge number of researches needed. In DIEP my evaluation is nowadays
>    in 1/1000 of a pawn. For a long time i had 1/200 of a pawn (in the time
>    i experimented with MTD), but now i have 1/1000 of a pawn. So a drop
>    of 0.20 pawn, which is a normal drop in DIEP, is in fact a drop of 200
>    points. Happy researching!

Even if the score dropped a whole pawn (1000 points in DIEP), this would
only be 10 or 11 zero-width searches (2^10 = 1024) assuming that you
bound the score in an efficient manner.  Also,  I can understand having
a high resolution within the eval routine itself, but does it really help
to have the output of the eval be in 1/1000 pawn units?  I wouldn't trust
the sum total of any eval routine to 0.001 pawns! Maybe you could
output the total eval in units of 1/100 of a pawn (or even less).

Actually, that is an interesting question.  Does anyone know what the
optimum eval unit is for searching?  I am talking here only about what
the eval outputs - not the unit used internally for calculating the eval.
I know that most programs use the same unit for both purposes, but I
wonder if that is really optimum.

 - Dan

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