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Subject: Re: What means lazy/plain alpha bounding?

Author: Robert Hyatt

Date: 15:16:53 02/07/01

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On February 07, 2001 at 16:22:12, Severi Salminen wrote:

>Hi!
>
>Thanks for detailed explanation.
>
>>1.  You might start the next iteration without a PV to guide the search.
>>Internal iterative deepening helps.
>
>Oh, a new term again: internal iterative deepening. I think this was the thing I
>wondered in Crafty's search.c. Do you use IID in other places than when you are
>in PV node and don't have a move to try? Has anyone ever tried to use IID in
>_every_ node? If it helps in the root why wouldn't it help in other nodes as
>well...

I use it at _any_ PV node (node where beta != alpha+1) that does not have a
hash move to search first.  If you use it at non-pv nodes, you will burn way
too much CPU time.




>
>>I don't do this in Crafty for lots of reasons.  Null-move + hashing can cause
>>false fail-highs on a null-window search, and if you automatically assume that
>>move is better, you will make horrible mistakes every now and then.  In crafty,
>>if the null-window search fails high and the re-search immediately fails low,
>>I pretend the fail-high never happened.
>
>I also think I'll skip the lazy alpha bounding and stick with the plain alpha
>bounding I seem to be using. I want to keep things as simple as possible.
>
>Severi



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