Author: Robert Hyatt
Date: 06:38:02 11/04/00
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On November 04, 2000 at 07:42:00, Ulrich Tuerke wrote: >On November 04, 2000 at 00:48:52, TEERAPONG TOVIRAT wrote: > >>Hi, >>Is fail-soft alpha beta too slow? >>I see most programs prefer fail-hard version. >>Thanks for any comment. >>Teerapong > >IMO, either methods has its benefit. I understand that fail-hard is a bit faster >than fail-soft because "best" is already initialized to alpha, whereas it's "- >infinity" in fail-soft. > >So in case, the search does successfully return a value out of the initial >alpha-beta-window, I expect fail-hard to be a bit less node-consuming. > >However, if you encounter a value outside the initial alpha-beta region, the >fail-soft algo may give you a bound out side alpha-beta, whereas fail-hard can >at most give the bounds alpha or beta itaself. > >Uli I'm not aware of anything that says that when using fail-soft, you _must_ start off at +/- infinity. I don't, for example, yet I still let the search return values outside alpha/beta. I found it slightly better because you get a bit better info out of the hash table. But it was only a "bit" better. Not a huge win. More important if you use mtd(f) of course.
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