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Subject: Re: Crafty question

Author: Robert Hyatt

Date: 06:43:15 04/25/01

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On April 25, 2001 at 04:30:11, Alvaro Jose Povoa Cardoso wrote:

>Does Crafty use fail-soft, fail-hard or a mix of the two?
>From the source code I understand that is a mix between the two.
>In a fail high it returns the higest score instead of BETA so this is fail-soft.
>In the hash table probing it adjusts ALPHA and BETA in a fail-soft manner.
>But in a fail low it returns ALPHA so this is a fail-hard.


Not quite.  It first sets alpha or beta to the bound from the hash table,
so it is still fail-soft.  _BUT_, when I fail high or low at the root, I do
not use this new bound to set the bound for the next search.  I did fail-soft
as it was needed when I played around with mtd(f) a couple of years ago...

I see no benefit to a normal PVS search.



>I'm I correct?
>
>Thank you
>Alvaro Cardoso



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