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Subject: Re: outline for alpha beta

Author: Peter Kappler

Date: 12:39:45 05/12/00

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On May 12, 2000 at 13:34:39, John Coffey wrote:

>My evaluation function is partially complete.
>I have move generation done, so now it is time to add the
>alpha beta search.
>
>I have seen pseudo code for alpha beta before but can no longer
>find it.  Could someone please direct me to a source.
>
>I have been confused by the terms "fail high" and "fail low"
>although I think that I understand the principles behind it.
>
>I would also like to see pseudo code for null move pruning.
>
>Thanks in advance,
>
>John Coffey

Hi John,

"Fail high" and "fail low" are only meaningful if your initial alpha/beta window
for a search is non-infinite.  This is commonly called "windowed-search" or
"aspiration-search".

For your first try I strongly recommend that you just forget about that stuff
and implement a vanilla alpha/beta search, with initial values of -MAXINT for
alpha and +MAXINT for beta for every iteration of your search.

Same advice for null-move pruning.  Leave that out until your basic search is
working.  Good luck, and have fun!!


--Peter






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