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Subject: Re: Schema for storing all possible legal positions in 24 bytes

Author: KarinsDad

Date: 12:15:01 05/17/99

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On May 17, 1999 at 14:18:13, Peter Klausler wrote:

>See the CDB internal documentation at http://reality.sgi.com/pmk_craypark
>for CDB's internal 24-byte packed format, which is a hell of a lot
>simpler than this approach.

Yes, the CBD format is a fairly sweet. My approach was an attempt to a) get
below 24 bytes and b) try something different. It actually goes down to 23 bytes
since it has been determined that 50 move rule and move by repetition is
worthless information in this type of a format.

Andrew has a simpler packed format than the one I mentioned above in my post
that fits into 22 bytes. His is currently at 174 bits, the same as the one you
mention below. If you could post the 174 bit representation that you mentioned,
I would appreciate it.

Thanks,

KarinsDad :)

>
>The smallest context-free representation that I know of is 174 bits
>per position, but it would take way too much time to use in a real
>chess program.
>
>In a database where positions need not be context-free it is of
>course possible to get much smaller.  Most positions in CDB 1.5
>are represented by 12-byte structures, and in CDB 2.0 they're
>down to 8 bytes.



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