Author: J. Wesley Cleveland
Date: 11:43:39 02/02/01
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On February 01, 2001 at 21:02:42, Vincent Diepeveen wrote: >On January 31, 2001 at 19:14:19, Dann Corbit wrote: > >>On January 31, 2001 at 11:36:01, Robert Hyatt wrote: >>[snip] >>>The idea seems pretty good for 3-4 piece files, and even for 5 piece files >>>although the memory to hold them becomes prodigous. But 6's are hopeless >>>as todays machines are no better at probing a 1gb file than they are at >>>probing a 1 terrabyte file. >> >>It might be worthwhile to store them in a real database with hashed index. >> >>Modern database systems will cache database requests very efficiently, and so I >>think it might be doable. The database model would be the hard part (finding a >>representation which is still highly compact like the tablebase files) > >If you don't store it in 2 bits but only win/draw/loss (in diep >i only generate legal moves so i can never get to illegal positions) >then you can store 5 positions instead of 4 in a single byte. > >Those compress very good. experiments of mine so far come down to >the size of 1 CD of 650mb for all 3,4,5 men. > I would guess that after compression the 4 per byte tables would be only slightly larger than 5 per byte tables, and might not be worth the extra decoding effort. >Your first big safe is the size in which you store. the second big big >safe is the better compression. > >Of course you can get them down even quite smaller but then you can't >quickly read them during a game unless you keep everything in RAM as >you need to do binary search on the positions then, >which no user except a few freaks with the latest >computers will do. > >The problem remains however generation. Also you'll not win KNNKP >that's the only price you pay when talking about 5 men :) If you have the HD space, it would be better to have both WLD and full tables, and always use the full table at the root.
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