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Subject: Re: 01/28/00 12:43PM 2,014,826,249 krbknn.nbw.emd ---- Size?

Author: Robert Hyatt

Date: 10:49:59 02/28/00

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On February 28, 2000 at 10:35:29, David Eppstein wrote:

>On February 28, 2000 at 08:45:32, Robert Hyatt wrote:
>>On February 28, 2000 at 03:00:24, Gregor Overney wrote:
>>>How large is KQQKQP? How about KPPKPP?
>>
>>First, you can forget kppkpp for a long while.  The file will be huge and there
>>are a _bunch_ of other 6-piece files that have to be completed first.
>
>I would think that all of the KxxKyy should be about the same size as each
>other, and all of the KxxKyz should be about the same size as each other.


It depends.  IE if the max mate is <= 127, then 1 byte per entry is enough.
If we get some that have a max mate in 400, they will take forever to compute,
and they will be bigger.  And then there is compression.  If a particular
ending is mostly drawn, the database compresses like crazy.  If it is not
mostly drawn, it doesn't compress as well.

Just check out the variability of the 5 piece files on my ftp site for a
comparison.



 Maybe
>if some of the pieces are queens the databases would be smaller due to much more
>limited king position.  So KPPKPP shouldn't be any more huge than some ones you
>already have.


Don't forget you lose a lot of symmetry with pawns...  if you use all the
rotation/reflection tricks, you end up moving pawns sideways and stuff like
that...




>
>The problem, as Bob says, is that to compute KPPKPP correctly you need every
>KxyKzw, and most of those really are huge (also to play KPPKPP perfectly you
>need to keep the other databases rather than throwing them away after computing
>KPPKPP, but that problem can sometimes be finessed).  It might be easier to
>compute an approximate (i.e. not correct but maybe still useful) KPPKPP database
>assuming no underpromotions -- but you would still need to work up to it through
>KQQKQP (should be computable now or soon), KQQKPP (probably computable soon and
>not very interesting), KQPKQP (big, but you could split it up into pieces
>according to the pawn files), and KPPKQP.



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