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Subject: Re: Storage idea (maybe Mr Corbit is interested)

Author: Angrim

Date: 14:55:22 10/23/01

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On October 23, 2001 at 17:06:14, Dann Corbit wrote:

>This brings a lot of questions to my mind.  If (for instance) we are actually
>representing 262,143 (less illegal) positions, how many wins/losses/draws are
>actually contained in the tablebase file?

No clue :) but it should be fairly easy to write a program to find out.
just iterate through all of the legal positions and do a tablebase probe.

>Is the compression based solely on the rotations of the board, or are mirror
>reflections used also?

reflections are used also, likely exclusively although I havn't
checked Eugene's code.  My own code uses only reflections
because they are faster to calculate than rotations.
For a pawnless endgame, there end up being under 500 unique ways
to place two kings on the board without touching.
With pawns, only left-right reflection can be used, which is why the
endgame table with pawns are usually much larger.

Angrim



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