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Subject: Re: When to stop searching?

Author: Bernd Nürnberger

Date: 06:02:52 05/03/04

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Hi Volker,

On May 03, 2004 at 08:18:48, Volker Böhm wrote:

>On April 30, 2004 at 08:26:59, Bernd Nürnberger wrote
[...]
>Hi,
>
>you can nearly never stop searching "earlier" except if and only if there is a
>recapture that proves to be the only move not loosing material.
>Even if alphabeta don´t varry much your engine could just find a tactical
>problem in the next millisecond.
>
In advance, thank you for your answer!

Ok, this sounds reasonable to me. But how does some engines manage it
to play a move really quickly then?  What I mean is, some engines does
some moves *really* fast, when considering the time control.  And the
corresponding moves are recaptures only in fewer cases.

>There are two point where you should search (much) longer.
>
>1. Your best move calculated from the previous interation fails low. At this
>point you should spend enough time to be sure that all other moves are searched
>too.
>2. If after your iteration the result drops below your initial alpha value. Then
>you should spend enough time to search again with a larger window. When the
>result is much smaller than before, you should consider to search the next
>iteration too.

Are these points also important, if I do a search with a -INFINITY, INFINTY
window from the root (the current position)?  So I should never get a fail high
on the first move, shouldn't I?

Greetings, Bernd



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