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Subject: Re: Fail-hard, fail-soft question

Author: Robert Hyatt

Date: 08:58:11 05/06/04

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On May 06, 2004 at 11:38:44, Dan Honeycutt wrote:

>Yet again I apologize for asking a question which I'm sure has been asked many
>times before, but could someone explain the difference between a fail-hard and a
>fail-soft and how does is affect a PVS search?
>
>I made the guess that, ie, if (score >= beta) if I return score it's a fail-hard
>and if I return beta it's a fail-soft.  It would seem that what I return doesn't
>so much matter as what I put in the hash table.  If I put in the (possibly)
>higher value of score then I have a higher lower bound and a greater chance for
>a hash cut if this position arises again.
>
>Thanks in advance.
>Dan H.

That is backward.  But you have the right idea.  Fail-hard never returns a value
outside the initial alpha/beta window.  Fail-soft does.




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