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Subject: Re: Interpreting my analysis of the Fine 70 position.

Author: Paul Clarke

Date: 07:51:07 07/15/04

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On July 14, 2004 at 13:24:53, Stuart Cracraft wrote:
[snip]
>Hi Dieter,
>
>Please see if you see anything obvious with my basic search.
>Any comment you make is welcome.
>
>search(depth,alpha,beta)
>   if draw-rules-met return draw
>   if extensions-met depth+=1
>   if depth <= 0 return quiesce()
>   try to retrieve hash position of current position
>     if length retrieved >= depth then
>       if flag is VALID, return score from hash table for position
>       if flag is LOWERBOUND, set alpha to MAX(score-from-table,alpha)
>       if flag is UPPERBOUND, set beta to MIN(score-from-table,beta)
>       if alpha>=beta return score
>       set flag meaning hashed

Shouldn't you be setting this flag regardless of the length retrieved? Otherwise
when you do an iteration at depth n you won't use the move found by the depth
n-1 iteration as the first move to search. (Probably just confusion in the
pseudo-code rather than a bug in the real code.)

>     endif
>    if null-move-ok, do it (not endgame, not incheck, not 2 in a row already)
>    if hashed flag above is set, add a value to make hashed move be searched 1st
>    generate moves
>    if hashed flag was set add value to make hashed move 1st

[snip the rest of the algorithm]



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