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Subject: Re: New BIT squishy idea

Author: Les Fernandez

Date: 10:45:54 11/13/01

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On November 13, 2001 at 13:21:42, Robert Hyatt wrote:

>On November 13, 2001 at 12:05:43, Les Fernandez wrote:
>
>>On November 13, 2001 at 10:09:30, Robert Hyatt wrote:
>>
>>Hi Bob,
>>
>>I am in the process of working on a different way of storing egtb's.  Keep in
>>mind that the method I am playing with allows me to store ie 28 chess board
>>positions, side to move , ce and pv in 50 bits (50/28=1.8 bits/position before
>>any form of compression).  The method I am researching guarantees that the pv is
>>no worse then what would be  reported from an egtb search but I can not
>>guarantee that the pv leading to mate is the minimal move.  As long as we know
>>the mate information, even though it may not be the most minimal, can still be
>>considered useful information.  Although this type of information may be found
>>to be useful, from a theoretical interest in the study of endgames I am still
>>counting on Eugenes tables.  The consequence to this method may be performance
>>with speed but conceptually it appears to be sound.
>>
>>BTW any idea with max compression what can be done with 1.8 bits??
>>
>>Les
>>
>
>I wouldn't venture a guess.  But the 1.8 bits certainly sounds impossible
>to me.  IE you said a _position_ in 1.8 bits...

Yep atleast I believe thats right but understand it is dependant on board setup.

Perhaps I need to elaborate.  With the method I am working on it was more or
less conceived for positions of <9 pieces.  Having not completed my work I can
provide you with some estimates of bits/position without compression:

                                   (but very close to worse case scenario)
                Approximate        Approximate
# of pieces     Low end (bits)     High end (bits)
     3               1.1                 4.2
     4               1.3                 4.9
     5               1.5                 5.7
     6               1.8                 6.4
     7               2.0                 7.2
     8               2.2                 7.9

I sure hope I did my math right <s>.


>
>As far as compression goes, it depends on how random the final data is.  If it
>has patterns in it, it will compress fine.   If it is totally random, it won't
>compress at all.

Well I guess that needs to be determined I am not very familiar with
compressiion techniques.



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