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Database storage methods
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Don Dailey



Joined: 29 Apr 2008
Posts: 4323
PostPost subject: Re: Database storage methods    Posted: Sat Mar 10, 2012 10:25 pm Reply to topic Reply with quote
hgm wrote:
Well, escapes can be viewed as a byte-quantized form of Hufman coding. If compactness is not the only criterion, but you also want to have some efficiency left on decoding, using SEE etc. seems a bad idea.

Decoding can be much faster, with an acceptable loss of compactness, by reserving codes for all possible move steps of the given piece type. You can then decode the move by just looking at the piece list section for that piece type to get the from square, and use a lookup table to get the step-vector. For orthodox Chess you would need 8x3 codes for Pawns, 3x8 for K+N, 4x14 for B+R and 28 for Q, for a total of 132. You would still need 8x3 codes for under-promotions, some of which could be also used for double-pushes, as Pawns that can double-push can never promote. (Castlings could be encoded as off-board King moves, as the King has to be on the edge to castle.) That leaves 100 codes for super-numerary pieces, of which you could set apart 8 for an extra N and 28 for an extra Q,R or B. That still would leave 64 codes with variable decoding (where you first would have to figure out what material is on the board to know what the codes mean) for the never-occurring situations with 3 and 4 Queens, 7 Knights or whatever, and some escape codes for positions so ridiculous that the 1-byte system cannot handle them.


Has anyone ever given consideration to how a compact opening book might be built using bloom filters or Golomb-coded sets?

It seems like a natural fit, except for the pesky false positive hit rate - a problem that I think makes this unworkable. With Golmob-coded sets we could (in theory) get a book down to something around 8 bits per position and still have transpositions detected.
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Subject Author Date/Time
Database storage methods david nash Thu Mar 08, 2012 10:56 am
      Re: Database storage methods Ed Schroder Thu Mar 08, 2012 11:59 am
            Re: Database storage methods Julien MARCEL Thu Mar 08, 2012 12:33 pm
                  Re: Database storage methods david nash Thu Mar 08, 2012 12:43 pm
                  Re: Database storage methods Martin Sedlak Thu Mar 08, 2012 1:00 pm
                        Re: Database storage methods Julien MARCEL Thu Mar 08, 2012 1:13 pm
                              Re: Database storage methods david nash Thu Mar 08, 2012 1:32 pm
                              Re: Database storage methods Martin Sedlak Thu Mar 08, 2012 1:45 pm
                                    Re: Database storage methods Julien MARCEL Thu Mar 08, 2012 1:51 pm
                        Re: Database storage methods Ed Schroder Thu Mar 08, 2012 3:42 pm
                  Re: Database storage methods Ed Schroder Thu Mar 08, 2012 3:46 pm
                  Re: Database storage methods Robert Hyatt Thu Mar 08, 2012 10:54 pm
                        Re: Database storage methods Julien MARCEL Thu Mar 08, 2012 11:53 pm
                              Re: Database storage methods Robert Hyatt Fri Mar 09, 2012 12:18 am
                              Re: Database storage methods Edmund Moshammer Fri Mar 09, 2012 12:51 am
                                    Re: Database storage methods H.G.Muller Fri Mar 09, 2012 9:29 am
                                          Re: Database storage methods Don Dailey Sat Mar 10, 2012 10:25 pm
                                                Re: Database storage methods Edmund Moshammer Sun Mar 11, 2012 12:27 am
                                                      Re: Database storage methods Don Dailey Sun Mar 11, 2012 5:25 am
                                    Re: Database storage methods Don Dailey Sat Mar 10, 2012 10:44 pm
                                    Re: Database storage methods Ronald de Man Sat Mar 10, 2012 11:45 pm
            Re: Database storage methods david nash Thu Mar 08, 2012 12:40 pm
      Re: Database storage methods H.G.Muller Thu Mar 08, 2012 4:36 pm
            Re: Database storage methods david nash Thu Mar 08, 2012 5:03 pm
                  Re: Database storage methods H.G.Muller Thu Mar 08, 2012 5:28 pm
                        Re: Database storage methods david nash Thu Mar 08, 2012 8:48 pm
      Re: Database storage methods Harald Lüßen Thu Mar 08, 2012 8:45 pm
            Re: Database storage methods david nash Thu Mar 08, 2012 8:51 pm
      Re: Database storage methods Nguyen Pham Thu Mar 08, 2012 10:39 pm
      Re: Database storage methods Vincent Diepeveen Sun Mar 11, 2012 6:41 am
            Re: Database storage methods david nash Sun Mar 11, 2012 4:49 pm
                  Re: Database storage methods Vincent Diepeveen Sun Mar 11, 2012 4:58 pm
                        Re: Database storage methods david nash Sun Mar 11, 2012 5:51 pm
      Re: Database storage methods Vincent Diepeveen Sun Mar 11, 2012 7:03 am
            Re: Database storage methods Vincent Diepeveen Sun Mar 11, 2012 7:21 am
            Re: Database storage methods Edmund Moshammer Sun Mar 11, 2012 9:21 am
                  Re: Database storage methods Vincent Diepeveen Sun Mar 11, 2012 3:41 pm
                        Re: Database storage methods david nash Sun Mar 11, 2012 5:08 pm
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