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Subject: Re: What approach do you use to handle castling/en passant for repetition?

Author: Robert Hyatt

Date: 10:51:25 02/28/00

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On February 28, 2000 at 09:17:48, Tom Kerrigan wrote:

>On February 28, 2000 at 08:49:06, Robert Hyatt wrote:
>>On February 28, 2000 at 03:25:09, Tom Kerrigan wrote:
>>>On February 27, 2000 at 18:00:32, Robert Hyatt wrote:
>>>>I don't believe this can be safely overlooked, because the wrong repetition
>>>>value is a tiny part of a much bigger problem, that of not correctly hashing
>>>>positions...  the former may not happen often.  The latter happens thousands
>>>>of times every search.  Often enough that it will _definitely_ affect the
>>>>root score enough to make a difference.
>>>I would like to see some numbers to back up your argument.
>>3, 47.5, 2.71828, 3.14159265358979323846264, and -.2
>>All you have to do is run with and without EP hashed into your signature to
>Exactly. I'd like you to do this [again]. And post some test suite scores
>comparing the two, or something.
>I know for a fact that some of the best programs don't hash this stuff, and they
>don't seem to be hurting _nearly_ as much as you suggest.

Who isn't including EP status in the hash signature?  I can't imagine _anyone_
not doing this.  It leads to simple failures that are easy to predict.

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