Re: [gentoo-user] Re: OT Best way to compress files with digits

[meino.cramer@gmx.de]

James <wireless@tampabay.rr.com> [14-11-01 18:16]:
>  <meino.cramer <at> gmx.de> writes:
> 
> 
> >  I have a lot of files with digits of PI. The digits
> >  are the characters of 0-9. Currently they are ZIPped,
> >  which I think is not the best way to do that.
> 
> Hello Meino,
> 
> It's a bit of effort, but the world's recognized authority
> on algorithms is Don Knuth. [1] He's old now, but his
> pioneering attempt at categorizing most algorithms:
> "The art of computer programming" and his MMIX alogrithm
> implementations (kinda like assembler) are certainly
> part of many first-step research efforts on algorithms
> and their implementations.
> 
> It's not a cookbook; more of a scholarly (high_brow) reference,
> just to supplement all the good postings by your peers on gentoo user.
> 
> Alan may loan you his copy?
> (ha ha ha)?
> 
> 
> 
> hth,
> James
> 
> [1] http://www-cs-faculty.stanford.edu/~uno/
> 

Hello james,

Don Knuth ... oh YES! :)
For a long time I am using and prefering TeX over anything else
(ok...for ASCII I use vim... ;).

And beside his computer wisdom I also like his kind of humor a lot...
for example this one:
https://www.youtube.com/watch?v=eKaI78K_rgA&list=PLUu0XRts4lK6Ri7-xaCNYqTHx7We95Rk8&index=10

But my initial question was more targeted to "practical computing" as
to groundshakeing and fundamental research topics.

More like "what tool to pick?"...

I did some compression tests myself and currently I have this:
From http://piworld.calico.jp/ (http://piworld.calico.jp/estart.html)
I got zipped package of
1000 million places of PI each (~57MB for one ZIP).

I unpacked the first package and recompressed it with different
methods of 7zip, gzip and bzip2. For gzip and bzip2 I used the highest
compression mode (-9). When a files name matches /.*ultra.*/, I used
the highest compression mode (-mx=9), else I only set the compression
method and leave the rest untouched (defaults).


 119888896 2014-10-31 16:44 pi-0001.txt
  57105419 2014-10-31 16:47 pi-0001.txt.gz
  52632832 2014-10-31 16:48 pi-0001.txt.bz2
  52045827 2014-10-31 16:54 pi-0001.txt.ppmd.7z
  57110291 2014-10-31 17:23 pi-0001.zip
  51766683 2014-10-31 17:26 pi-0001.txt.lzma.7z
  51668838 2014-10-31 17:34 pi-0001.txt.lzma.ultra.7z
  52862115 2014-10-31 17:36 pi-0001.txt.ppmd.ultra.7z
  51668838 2014-10-31 17:39 pi-0001.txt.ultra.7z

7zip's lzma wins here, which is also the default method of 7zip. I set
the ultra mode for this by hand.

From other sites which offer PI for download I know of methods, which
store the ASCII-digits in binary and compresses then. Would be
interesting, whether this creates a more "handy" input from 7zips
point of view...

Ah! By the way...I was astonished to read, that the digits of PI are
called random on the one hand and on the other hand there is a formula [1] 
to calculate a certain digit of PI without calculation of the previous
digits...
Calculated random? Are nature constants the purest form of PRNGs ??? ;)
(Quantum physics is everywhere... ;;))

[1]: http://en.wikipedia.org/wiki/Bailey%E2%80%93Borwein%E2%80%93Plouffe_formula

Best regards,
Meino