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Subject: Re: Hash tables vs alpha/beta

Author: Ernst A. Heinz

Date: 08:31:14 01/17/00

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Hi Peter,
> [...]
>
>That doesn't work well with my program which has a PVS-based alg.
>When re-searching a move, the A/B-window will be narrowed down in
>the tree based on the 3L and 3U cases above and a FailHigh together with
>a cut PV-line will be the result.

If I understood your problem correctly, you have to add a second
"upper" bound value to your code that the search respects on
subsequent fail highs. You initialize this "upper" value with the
upper bound drawn from the hash table. See my article about
"Efficient Interior-Node Recognition" in the ICCA Journal 21(3),
pp. 156-167, Sept. 1998 for more details.

A preprint of the article is available on the WWW pages of
"DarkThought" at URL http://supertech.lcs.mit.edu/~heinz/dt/.
The subsection on "Recognizer Results" should be of specific
interest for you.

Hope this helps,

=Ernst=

P.S.
BTW, you will find more information about this topic in my new
book about "Scalable Search in Computer Chess" which is now
available at Amazon.de and MKP online.

http://www.amazon.de/exec/obidos/ASIN/3528057327/
http://www.mkp.com/books_catalog/3-52805-732-7.asp

Visit http://supertech.lcs.mit.edu/~heinz/node1.html for more
information about the book.



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