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Subject: Re: Unable to improve alpha

Author: Tord Romstad

Date: 06:17:17 07/25/04

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On July 25, 2004 at 09:10:19, Stuart Cracraft wrote:

>So at the root, in the opening position, I play e4.
>At the third ply of iterative deepening, the program
>hits the position after 1 e4, e5; 2 Qh5, Bc5; 3 Qxe5. No
>null move has been played here due to being in check.
>The program now cycles through the only legal black
>replies of 3 ... Ne7, 3 ... Be7, 3 ... Kf8, and 3 ... Qe7.
>Going into this, alpha is -6 from the previous position.
>None of these moves improves alpha and this value is
>returned with no best move stored in the hash table.
>
>My question is: is this a problem or expected given
>the position?

This sounds like the expected behaviour.  At a node where
the search fails low (i.e. no move brings the score above
alpha), there is no way to know which move is best.  If I
understand your description correctly, you have no problem
to worry about.

Tord



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