[Tutor] Re:Base 207 compression algorithm

[cino hilliard]

The number compression ratio for my base 2 - 207 compression algorithm  is 
log(10)/log(b). Thus if we
compress a 1000000 digit number base 10 to base 207 we have a compression 
ratio of log(10)/log(207)
= 0.43178... The best we will be able to do with a character set with codes 
up to 999 is about 1/3.

Thanks,
  3         3        3         3        3        6            2              
  (0^0)
2   +  13  +  33  +  43  =  49   =  7    =  343   = 117649





>From: "cino hilliard" <hillcino368@hotmail.com>
>To: tutor@python.org
>Subject: [Tutor] Re:Base 207 compression algorithm
>Date: Thu, 26 Jun 2003 19:32:01 +0000
>
>To:Jeff Shannon and all other Python users
>
>Cino Hilliard wrote:
>>># we can determine the compression ratio for various bases. # Eg., base 2 
>>>= 332%,
>>># base 8 =111%, base 10 =100%, base 100 = 50%, base 207 = 43.2%.
>>
>>
>Jeff Shannon wrote:
>>This is mistaken, because you're only changing how many characters are 
>>used to display it on the screen.  No matter what base it's displayed in, 
>>it is still *stored* in binary, and this will not compress anything. 
>>Whether you see 'FF' or '255' or '@' (or whatever other character might be 
>>used to represent that number in whatever base you try to use), it still 
>>must occupy one byte of memory / hard drive space.  Once again, you're 
>>confusing the display with internals.  Changing the base only affects 
>>display.
>
>Does anyone else in the python community agree with this?
>
>
>Attached is a script that can be used to zip numbers. It is a base 2-207 
>compression algorithm that I
>developed using python's arbitrary integer precision feature. Base 207 was 
>used for the output in this
>example.
>
>Here is the output for 5000 digits of Pi stored to two files pib10.txt for 
>the decimal expansion and
>pib207.txt for the base 207 conversion. I included Win Zip and pkzip files 
>also. You will notice that the
>compression in base 207 gives a better ratio than the Zip file compression. 
>The compression ratio
>improves logorithmically with increasing bases.
>
>
>Also shown is the compression for 1000! in base 207.
>
>This is in no way intended to imply that this code is better than the 
>professional zip code. It is just a
>demonstration of ways to compress a string of numbers using base 
>conversion. Currently, it only works
>on numbers.
>
>
>C:\Python23>dir pib*.*
>Volume in drive C has no label.
>Volume Serial Number is E834-0F93
>
>Directory of C:\Python23
>
>06/26/2003  12:37 PM             5,000 pib10.txt
>06/26/2003  12:37 PM             2,159 pib207.txt
>06/26/2003  12:44 PM             2,665 pib10.zip
>06/26/2003  01:34 PM             2,594 pib10pk.ZIP
>06/26/2003  02:02 PM             2,568 fact10.txt
>06/26/2003  02:02 PM             1,109 fact207.txt
>
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