Author: Dann Corbit
Date: 15:17:11 01/28/02
Go up one level in this thread
On January 28, 2002 at 18:09:53, Vincent Diepeveen wrote: >On January 28, 2002 at 18:03:03, Les Fernandez wrote: > >>On January 28, 2002 at 17:55:24, Scott Gasch wrote: >> >>>On January 28, 2002 at 17:48:48, Les Fernandez wrote: >>> >>>>Just curious to know what is the best being done now for storing a chess >>>>position. In the worse case scenario (castling right exists) it takes me 162 >>>>bits to store 32 pieces, color, location, side to move, castling, enpassant, >>>>promotion, ce and pv. Now if castling rights do not exist then the worse case >>>>scenario for the above is 81 bits. Much further reduction in bits/position is >>>>possible but at the moment I am interested in the above. >>>> >>>>Thanks in advance, >>>> >>>>Les >>> >>>How can you have a 162 bit requirement with castling rights and a 81 bit >>>requirement without castling rights? You're telling me you need 81 bits to >>>store castling information? Here's a breakthrough for you: >>> >>>0000 = no castling possible >>>0001 = white can castle short >>>0010 = white can castle long >>>0100 = black can castle short >>>1000 = black can castle long >>>1111 = all castling possible >>> >>>Scott >> >>I am aware of how many bits you need for castling. I did not say I needed 81 >>bits for castling I merely said that in positions that have no castling rights >>that I need only 81 bits to store the position. Before you challenge my bits >>needed to store castling rights you might be more interested to know how does >>one store the entire position using only 81 bits <S>. >> >>Thanks > >please explain how to store the position in 81 bits when castling doesn't >matter. See this word document, referenced below: As Professor Clouseau once said, "And the mystery, she is solved": ftp://cap.connx.com/pub/les/cp.doc It's a word document. Might get some revisions in the near future, but it explains it well enough. Here's another breakthrough which will reduce the 162 bits back to 81: Have 6 files, one for each castling status. Then, you need no bits, because the castling status is implicit by the file type.
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