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Subject: Re: Q: Singular extensions

Author: Bas Hamstra

Date: 16:24:31 01/05/04

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On January 05, 2004 at 08:48:23, José Carlos wrote:

>  Hi, I'd like to try singular extensions in my program. I've been trying to
>think about it and all my tries so far result in worse performance. After some
>web search I haven't been able to find anything but the general idea described.
>  Is there any good description somewhere? Some pseudo-code? I guess there must
>be something interesting in the archives but I can't download all of them.
>  Thanks in advance,
>
>  José C.

Here is what I tried (idea from Bruce I believe):

Before you search all moves (after nullmove) you search all moves (unsorted)
with D-R and check if there is one and only one move with a score above alpha
*and* above Alpha-Margin. If so, in the normal search to depth D extend that
move. I did not do this in nullwindow searches, or else performance crashed. No
great results. In particular I didn't see much spectacular long pv's show up.

I am interested in refinements or other approaches. And are there good
testpositions to check the effect of SE?


Best regards,
Bas.












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