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Subject: Re: Root Search Question

Author: Gian-Carlo Pascutto

Date: 04:17:22 12/27/99

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On December 27, 1999 at 00:07:47, William Bryant wrote:

>If your search fails low on the root PV move.
>(IE. the full alpha beta window for the PV move returns a score <= alpha
>and nothing is backed up into the PV array).
>
>Do you?
>4) Do Nothing?
>	Continue the rest of the root moves within the -alpha-1, -alpha PVS >window.
>	Only search moves outside the PVS window for the rest of this iteration
>	if they return a score > alpha on the PVS search.  Hope that if the
>	every root move is going to fail low, that this will speed up the
>	search until the window is lower.

I do it like this.(*) This has the additional advantage that a non-PV node may
fail high, so you only have to research that move, and nevermind about the
fail-low earlier in the list.

>Fail low on the root move seem to bring my search to a crawl and I'm looking
>for a way to be more efficient.
>

A fail-low on your PV move is always going to be bad, no matter how you handle
it.


(*) That is, since yesterday.

--
GCP



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