Author: Robert Hyatt
Date: 20:37:54 02/10/02
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On February 10, 2002 at 18:55:59, Angrim wrote: >On February 09, 2002 at 22:35:54, Robert Hyatt wrote: > >>On February 09, 2002 at 11:26:00, Joshua Lee wrote: >> >>>How do you determine the space necessary for each additional piece? If we know >>>all 6 man will take over 1 TerraByte what about figuring out the 7's, 8's ....to >>>32 and up? I personally think the only way to fit it all in less space is to >>>make a new kind of Tablebase but since the compression is already good this >>>would be hard to do. >> >> >>Several issues: >> >>1. 6 piece files are going to require some large mate-in-N scores. IE they >>will need 16 bits at least, which doubles the size compared to a current 5 >>piece file where all scores are 8 bits max. > >This doubles the size of the file before compression, but has little >effect on the size of the compressed file. At least as long as the >majority of the positions in the file are relatively short mates or >draws. Only the positions which are long mates will take extra >space after compression. Compression could be further improved by >switching to building DTC tables. > Think about that a moment, and you will see it is a flawed statement. IF the file is 2x larger _before_ compression it will most likely be 2x larger _after_ compression. Otherwise you are saying that larger files compress more than smaller files which is a simply flaw in reasoning. >>2. another piece multiplies the size by roughly 60. > >yep. >>3. Unknown compression ability. We already have some 6 piece files that >>are 3+ gigabytes. These are pawnless which have max symmetry. Pawns will >>increase that significantly. > >I assume that is 3gig before compression. I would expect that >6pc tables with one pawn(ie. KRPvKRN as a possible worst case) to >take around 3GB compressed. No.. That is 3 gigs _after_ compression. > >Angrim >ps. in theory, the KKK vs KKK suicide chess EGTB is small enough to >build on my home machine.. >In practice, I'm not *that* bored.
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