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Subject: Hash Depth Question Was Re: Please help with a bug in my program

Author: Brian Richardson

Date: 07:23:31 09/08/02

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On September 08, 2002 at 08:45:12, Robert Hyatt wrote:
snipped
>I am not sure what you mean.  But the answer is to look at your search code,
>and pick a position and ply where you are going to probe the hash table when
>you enter search.  remember that number.  Now assume you don't get a hit, so
>do a normal search, and look at the two ways to get out of search:  (1) you
>get a fail high;  (2) you don't.  Make _sure_ that at each of those two
>places, you store the _same_ depth you used when you probed the table at the
>start of this search.  If not, you have a problem...

Bob:  Could you try to explain why this might be a problem.  The scenario is:
upon entering the search routine at a new (deeper) ply n, the hash table is
probed.  If the search continues, extensions (e) can get added to the depth.
Moves get searched and then the resulting bound or exact value is stored with a
deeper depth n+e than was originally probed.

Ok, the question is, next time this position is probed, even if it is at the
same original (n,  or lower depth), wouldn't the "deeper" n+e hash depth search
value still provide a valid result?  Or, deeper is always better, right?

Thanks.



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