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Subject: Thank you :)

Author: Edward Seid

Date: 15:32:50 09/29/03

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On September 29, 2003 at 12:46:29, Gian-Carlo Pascutto wrote:

>On September 29, 2003 at 12:42:24, Edward Seid wrote:
>
>>A couple of questions:
>>1 - should it read alpha > beta or alpha >= beta?
>
>alpha >= beta, see my self-correction
>
>>2 - some pseudocode examples initialize score = NEGATIVEINFINITY before
>>generating the moves.  I haven't done this in my code.  Is it necessary?
>
>In the current version it is not needed. You need to set score to -inf
>only if you return score instead of alpha at the end, which you don't do.

Thanks for pointing out the error in the command order of my alpha-beta
algorithm.
Using a test position, my flawed version evaluated 304,789 nodes, while the
corrected version evaluated 170,040 nodes.  In general, I'm seeing around a 40%
improvement using the corrected version.



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