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Subject: Re: Fractional search depth

Author: Tony Werten

Date: 05:16:27 11/26/02

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On November 26, 2002 at 06:15:11, Vladimir Medvedev wrote:

>There can be two ways to implement fractional search depth (very useful in
>extensions, for example):
>
>AlphaBeta( int remain_depth, ...)
>{
>   if( remain_depth <=0 ) return QSearch();
>   ...
>   for(...){
>      AlphaBeta( remain_depth - HALFMOVE, ... )
>   }
>}
>
>or
>
>AlphaBeta( int remain_depth, ...)
>{
>   if( remain_depth <HALFMOVE ) return QSearch();
>   ...
>   for(...){
>      AlphaBeta( remain_depth - HALFMOVE, ... )
>   }
>}
>
>In the first case, when we increase search depth by extension = 0.7 * HALFMOVE
>(at each depth), we get one additional ply the first time, then no additional
>ply.
>
>In the second case, the search depth (in full) plies will not be increased
>immediately, but we'll get extension on depth+1.
>
>I suspect these two methods both are correct, but which one is more idiomatic?

Second one, since the first one will start a new search when remain_depth = 1
thousands of a pawn.

If you want the behaviour with 0.7*HALFMOVE being a full ply the first time then
at the first ply use (searchdepth+ 0.5*HALFMOVE )

Tony




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