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Subject: Re: Question about Bit storage

Author: Dann Corbit

Date: 11:35:56 01/29/02

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On January 29, 2002 at 14:11:47, Uri Blass wrote:
[snip]
>>No.  His notion is that if you mirror using every symmetry, the total number of
>>those positions (including ALL reflections) would be less than 2^81 in that
>>category.
>
>If this is his point then he is wrong.
>
>The number of reflection of the same position is only 4 so the total number of
>classes of 4 positions is only 1/4 of the number of positions and it cannot be
>less than 2^81.

I was unclear.  You should read his document.  It also included all motions of
the sliding piece to the winning position.  Be aware that this system does not
produce a sure best move.  It could be thought of as producing a winning bound.

If you look at the list of positions Les posted, all 44 of them were generated
by a single position.  I suppose if you read the document:
ftp://cap.connx.com/pub/les/cp.doc
it will be immediately clear to you.

It could also be used to produce alpha/beta bounds for moves that are analyzed.
Again, it might not produce the best possible move.  But it could produce a
bound that you know it cannot be worse than that.  So, in a sense, it could also
be used to create an inexact information database for move choices.

You would get similar compressions for arbitrary positions at the beginning of a
game.



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