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Subject: Re: what does "fail high" mean? In the context of iterative deepening/

Author: Russell Reagan

Date: 20:38:44 11/30/02

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On November 30, 2002 at 20:55:54, scott farrell wrote:

>if it was 3.03-3.77 as you suggest, a few things would need to have happened:
>
>Nf6 would have needed to fail low
>Possibly several other moves would have needed to fail low
>Nf4 failed high
>
>So what I am saying is that, for this analysis only, that a wider window would
>reduce the chance of Nf6 to fail low, and hence why I think it was a
>narrow/narrower window.

Ok I'm still learning and trying to understand this better. Let's take an
example. Let's say that in this example from Monsoon, we got the result after 10
plies of Nf6 with a score of +3.02. Now when we do our 11 ply search, what do we
set the aspiration window to? If 'score' is the score from the previous ply
(which is +3.02 in this case), and 'n' is the width of the search window, then
do you set your aspiration window to (score, score+n)? Bob gave the example of
using (0,2*score). Obviously there are a lot of ways you could set your
aspiration window. How do you know what is safe and what is not? For example, I
suggested (3.02,3.77) and you said that it might be unsafe, and other things
would have needed to happen for this to be safe. So how do you determine how to
set the upper and lower bounds for your aspiration window?



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