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Date: 23 Oct 2007 06:54:07
From: Harald Korneliussen
Subject: Question related to Zobrist keys
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Hi, I'm looking for literature on certain algorithms, or perhaps you
could say I'm looking for algorithms for a certain task. It's not
directly related to computer chess, but I thought maybe people here
could give me a hint where to look.

I read about the technique of Zobrist keys, where you generate a
random 64-bit key for each square/piece combination, and combine them
to generate good hashes for chess positions. Now I wondered: would it
be possible to make this technique symmetry-aware, so that it
recognizes a given position even if rotated or mirrored?

It would not do much good in chess, I admit. But there are other games
where it would be a huge help.

I've done attempts at working out schemes for it, but with little
success. I suspect that it could be worked out (or perhaps be proven
impossible?) with some abstract algebra, but I unfortunately haven't
studied abstract algebra... Anyway, I'm sure this opportunity has
occurred to other programmers with interest in strategy board games?
Anyone know of any good articles, links, books?

- -Harald Korneliussen

(I sign because some lowlife is currently posting under my
credentials. All my posts should be signed with this key.)
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Date: 23 Oct 2007 23:23:27
From: Harald Korneliussen
Subject: Re: Question related to Zobrist keys
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On Oct 23, 4:28 pm, David Richerby <[email protected] >
wrote:

> That doesn't work. You could be the fake, trying to convince us that
> you're real by signing posts with a key that the real Korneliussen has
> never seen.
>

Would it make a difference to you, who don't know me? You know I'm the
same as last time, which should be enough.
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Date: 23 Oct 2007 15:28:23
From: David Richerby
Subject: Re: Question related to Zobrist keys
Harald Korneliussen <[email protected] > wrote:
> (I sign because some lowlife is currently posting under my
> credentials. All my posts should be signed with this key.)

That doesn't work. You could be the fake, trying to convince us that
you're real by signing posts with a key that the real Korneliussen has
never seen.


Dave.

--
David Richerby Flammable Boss (TM): it's like a
www.chiark.greenend.org.uk/~davidr/ middle manager but it burns really
easily!