Author: leonid
Date: 19:11:10 09/29/00
Go up one level in this thread
On September 29, 2000 at 20:03:02, Larry Griffiths wrote:
>On September 29, 2000 at 19:11:17, Bo Sjögren wrote:
>
>>Some time ago, maybe a year or so, there was an interesting
>>discussing about the minimum number of bits necessary to store an
>>arbitrary chess position. What was the conclusion of the
>>discussion? Can I find the discussion in the archive, or a
>>summary somewhere on the net?
>>
>>Regards,
>>Bo S
>
>I store mine in 32 bytes (256 bits). Each 4 bits contains the piece and its
>color as follows...
>
>cppp
>
>where c is the color and ppp is the piece (could have up to 8 piece types).
>
>OR
>
>If you really like to pack bits you could have a fixed array of 6 bits times 32
>bits (192 bits) where each of the 32 buckets has the square the piece is setting
>on.
>The problem with this second arrangement is that you would need another 8
>buckets for each side (32*6bits+16*6bits=288 bits) if promotions occurred.
>
>Neither of these arrangements include bytes to hold the en-passant status of the
>board or castleing state.
>
>Larry.
I do save each position of chess board with 64 bytes. Every of those 64 bytes
have three not used bits.
5 busy bits are: 3 bits - description of piece.
1 bit - empty, occuped square.
1 bit - color for piece, if square is occupied.
Leonid.
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