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Subject: Re: New stuff on Ed's page

Author: Vincent Diepeveen

Date: 08:35:25 12/30/02

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On December 30, 2002 at 03:49:40, Ed Schröder wrote:

>On December 29, 2002 at 19:35:52, Martin Giepmans wrote:
>
>>On December 29, 2002 at 19:05:51, Tony Werten wrote:
>>
>>>http://members.home.nl/matador/chess840.htm
>>>
>>>Tony
>>
>>The formula for reductions 2b and 2c look strange:
>>"alpha < score + threat + margin --> reduce depth ..."
>
>The formula is okay, read the purpose of the reduction:
>
>"The idea is, reduce the depth in case the score plus the (material) threat plus
>an extra margin still does not get it to ALPHA the future of this subtree isn't
>very promising, thus reduce."
>
>
>
>>This would imply that a bigger threat gives more reductions ...
>>Should be score - threat - margin?
>
>No. But maybe you we have a different understanding about ALPHA? Maybe you mixup
>ALPHA with BETA? It wouldn't be the first time :)
>
>Ed

I guess the mistake Martin makes is that he is too much busy
reducting at the top of his search. whereas you reduce directly *after*
making a move. After making a move is in general smarter unless you know
what you do at top of the search.

At top of the search alpha becomes beta and < becomes >  :)



>>Martin



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