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Subject: Re: 6-piece EGTBs (Repost)

Author: Mike Hood

Date: 14:40:41 04/02/02

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On April 02, 2002 at 16:32:54, Guido wrote:

>On April 02, 2002 at 13:27:10, Mike Hood wrote:
>
>>The normal figure thrown about for the size of a complete 6-piece egtb
>>collection is "about a terabyte". Can we try to make this figure a bit more
>>accurate? In the tablebase generation program the file size calculation is
>>separate from the generation itself, so it should be possible to calculate the
>>size of the uncompressed files exactly. When we have that we can make an
>>estimation of the size of the compressed tablebases (approx 20% of the
>>uncompressed size). And when we have that figure we can sit back and watch the
>>developments in storage media to see when 6-piece TBs become technically
>>feasible. Constellation 3D promised their FMD technology would produce optical
>>disks with a capacity of 1.5 terabyte, but they've failed to deliver so far.
>>
>>There should be 365 6-piece tablebase pairs of varying importance, in three main
>>groups:
>>
>>Kxx-Kxx : 120 tablebases
>>Kxxx-Kx : 175 tablebases
>>Kxxxx-K :  70 tablebases
>>
>>If we have the size for each group we'll know how much space a person needs on
>>his hard drive to generate KPPKPP, KPPPKP and KPPPPK respectively. Or someone
>>can fire up his university's supercomputer.
>>
>>Maybe it's just an academic pursuit at present, but technology has a habit of
>>overtaking you when you least expect it.
>>
>>And when we've finished with the 6-piece tablebases, what about the 1001 7-piece
>>egtb's?
>>
>>Kxxx-Kxx : 525 tablebases
>>Kxxxx-Kx : 350 tablebases
>>Kxxxxx-K : 126 tablebases
>>
>>I bet you're all dying to get your hands on the KBBBBBK tablebase ;)
>
>For uncompressed endings I obtain these values:
>
>No. men       Different                 Space
>               Endings                  in Mb (1Mb = 1024^2)
>
>   2              1                      ---
>   3              5                     0.275  (kbk and knk excluded)
>   4             30                   152.333
>   5            110                31,865.260
>   6            365             5,150,003.501
>   7           1001           611,686,390.198
>   8           2520        59,916,917,072.203
>
>Values reported are the result of an exact calculation using double precision
>floating point, but they_are_depending_on_the_indexing_scheme adopted.
>So they can be larger or smaller of the correspondent values obtained by other
>indexing scheme.
>Of course if the program is correct ...
>
>In details for 6 and 7 men:
>
>Kxx-Kxx        1,992,702.965      120
>Kxxx-Kx        2,525,840.429      175
>Kxxxx-K          631,460.107       70
>               -------------      ---
>               5,150,003.501      365
>
>Kxxx-Kxx     382,303,993.874      525
>Kxxxx-Kx     191,151,996.937      350
>Kxxxxx-K      38,230,399.387      126
>             ---------------     ----
>             611,686,390.198     1001
>
>Ciao
>Guido

So, assuming a 20% size after conversion, the total size of the 365 6-piece
tablebases would be 0.98 Terabytes. So the estimation of 1 Terabyte being thrown
around isn't too far off. Thanks, Guido. That's all I wanted to know.




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