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Subject: Re: Chessmaster selectivity

Author: Brian Smith

Date: 11:19:04 08/09/99

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On August 09, 1999 at 09:13:54, Shep wrote:

>On August 09, 1999 at 07:48:22, Harald Faber wrote:
>
>
>>Don't forget there is danger to overlook some good move the higher the
>>selectivity is...
>>Genius and Shredder have 12...
>
>I think there is a difference to CM.
>
>For Genius and Shredder, the formula is
>   MaxDepth = Brute Force Depth + Selective Depth
>Therefore, if you set Shredder's selectivity to "12" and it is currently
>searching ply 9, it will not look at any line deeper than 21=9+12 ply.
>
>The same is not true for Chessmaster.
>Even with SS=0, when at ply 6, it is looking deeper than 6=6+0 ply as you can
>see by its search display.
>I rather believe that the SS setting is some more abstract number, like "don't
>use this extension if SS less than 7" or "follow capture extensions to at least
>SS/2+5 ply" or something...
>
>---
>Shep



I think the Selective Search works this way:

Example:  Search at 4/12 ply
	This means that CM searches all possible moves for the next 4 moves (brute
force) and then selective search (not all possible moves) to the 12th ply--4
brute force + 8 selective search.  Of course, like any other program CM uses
extensions.  If there is a capture for example, or a mate threat, or whatever
else extensions there are in TheKing (the extensions, of course, are pretty
complex) then it extends the search beyond the 12th ply.

I'm pretty sure this is the way it works, not by interpreting the "thinking
lines" but also by interpreting the things Johan de Koning has said.



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