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Database storage methods
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Martin Sedlak



Joined: 26 Nov 2010
Posts: 701
PostPost subject: Re: Database storage methods    Posted: Thu Mar 08, 2012 1:45 pm Reply to topic Reply with quote
JuLieN wrote:
mar wrote:
Good idea Julien except that I think this can't handle transpositions Wink


Yep, she mentions the problem of course. But she wrote that in a time where storing 100k moves in 100k bytes was mandatory, considering the small available space on... those big 5"25 floppy disks. Wink

The solution to the transposition problem Ken told her was to have special codes for special cases. She gives actually two possible solutions to the transposition problem, and I quote her again:

Quote:
For example, bit code "11000011" might be used to indicate that the computer should recognize, but not play, the following move*. While code "11000100" might mean that the position already reached is a transposition of moves elsewhere in the book. In that case the next byte or two bytes might contain a pointer to another location of the book. Transposition can also be handled by "walking" the tree to see if the given position is present somewhere in the book. With a minimum of optimization to avoid examining lines that cannot possibly lead to the given position, the time cost for walking the tree is quite reasonable.**


* this is to name openings but don't play them if they are losing. Or, precisely, to avoid opening traps.
** And this was written for 1983 hardware Wink

Yes I'm aware of that and I really like Sargon and know when it was written. Dan and Kathe are legends.
The idea with using a code that a move leads elsewhere in the book can handle some but not all transpositions. You would have to generate all lines which lead to the same position in the tree which is impossible of course. So I would go for hashing for sure Wink

What I am missing however is an open opening book (tree) format what would

- support different hash sizes (64-bit or 128, 192 and 256-bit for large books)
- have exact formula and rules to calculate hashes (i.e. no tables)
- handle >4G files
- be platform independent and thread safe (in case it's needed)
- handle more than orthodox chess (variants etc.)
- be compact yet having small memory footprint and very good access time
- allow for dynamic updates
etc.

Not an easy task to do, what do you think? Would be very nice though. I can imagine open source lib under MIT license... sure polyglot is good and lightweight but...
Does something like that already exist?
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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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