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Subject: Re: Aspiration window

Author: Antonio Dieguez

Date: 13:58:05 01/21/02

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On January 21, 2002 at 16:50:21, David Rasmussen wrote:

>On January 21, 2002 at 16:30:22, Bas Hamstra wrote:
>
>>On January 21, 2002 at 15:56:59, Antonio Dieguez wrote:
>>
>>>>It should matter in quiet positions, right?
>>>
>>>Well, It should matter depending on how often the pv changes, so may be more in
>>>unquiet positions.
>>>
>>>>Well, here is data, opening
>>>>position:
>>>>
>>>>Rootwindow <-inf, inf> takes 2404K nodes
>>>>Rootwindow <-50, 50> takes 2420K nodes
>>>>
>>>>...to complete 10 ply.
>>>
>>>strange, I don't know the logic there, i would have guessed a bigger
>>>difference. please don't be angry but if that is what I would get in amyan
>>>regularly I would be sure it has a bug or I made a mistake in the experiment.
>>
>>It is possible of course, but I don't think so. It just don't seem to buy me a
>>lot. As far as I know it has never been proven anyway. Plus (based on only a
>>couple of tests) I simply don't see it here.
>
>I've just tried with my engine. I tested the initial position, wac.epd and
>bk.epd. In all cases, no aspiration window was better! Wow. I am surprised. It
>wasn't a lot better, but it wasn't worse, and it was simpler.
>
>It did surprise me however, that I solved 2 positions less in wac. At first I
>thought I had a bug, but now I don't. I have looked at the searches for the
>relevant position, and it just seems that hash tables are filled with different
>things in the two cases. While scoring two less isn't good, it is only 0.5
>percent or so. I don't know if it matters. I think I will make an engine -
>engine match between the two versions. If I could skip aspiration window, I
>wouldn't have those false fail-highs at the root.
>
>/David

you guys have me puzzled...
do you printf the move when it is failing high?
you obtain the same results in "normal" positions?
...?



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