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Subject: Re: How I store and handle bounds

Author: Martin Giepmans

Date: 10:30:39 04/19/04

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On April 19, 2004 at 13:11:59, Andrew Wagner wrote:

>Some have suggested this could possibly be a problem with how I store and
>retrieve the bounds in my hash table, so let me explain what I do and see if the
>logic is right. Much of it comes from Bruce Moreland's web site.
>
>My Search function calls a function called ProbeHash(). Probehash looks in the
>Transposition table to see if the position has an entry stored there already. If
>so, and the leaf distance of the hash entry is >= the current leaf distance, it
>looks at the score and at what type of entry it is. If it's a beta entry (stored
>when the move fails high), and the score is >=beta, Probehash returns beta. if
>it's an alpha entry (stored after a fail high), and the score is <=alpha, alpha
>is returned. If it's an exact score (the first time it was searched, the score
>was between alpha and beta), the score itself is returned. If none of this is
>true, it passes back a best move as a parameter. Once we arrive back at
>Search(), if any of the above three cases with scores (alpha, beta, or the hash
>entry score) were returned, Search immediately returns that score. Otherwise, it
>continues on.
>
>I hope this makes sense. Does this sound correct to the rest of you? Dan, is
>this similar to the logic of how you do it? Thanks! Andrew


Looks okay to me. Just to be sure, what happens if you don't use the alpha-score
and treat the exact score as if it were a beta score (or don't use it at all)?
It might not find Kb1 fast in that case, so let it run for a while ...



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