Computer Chess Club Archives




Subject: Re: Hashing double bounds

Author: Vasik Rajlich

Date: 01:44:24 06/21/05

Go up one level in this thread

On June 20, 2005 at 16:58:19, Dieter Buerssner wrote:

>On June 20, 2005 at 16:55:26, Robert Hyatt wrote:
>>This is more common for mtd(f) programs, since the same position may fail high
>>one search, and low the next, as the window passes over the true score.  For
>>non-mtd(f) programs, two bounds is worthless.
>We could read here, that Fabien is using 2 bounds for a non MTD(f) engine. I
>myself tried it, and I failed to make progress by it. Actually, the contrary
>happened :-( For a while, I tried hard to find out, why this happened - then I
>just gave up.

I also use two bounds together with PVS, it seems simpler. There might be some
_extremely_ rare difference in cases where you do three re-searches from the
root, but if your driver opens the window completely after an initial fail
low/high at the root, then I guess it make absolutely no difference.

The real reason I do this is I still have some secret hopes to later use smaller
aspiration windows from the root (or even MTD (f) :)).


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