Re: Compression of random binary data

From	Sylvia Else <sylvia@not.at.this.address>
Newsgroups	sci.physics
Subject	Re: Compression of random binary data
Date	2016-07-12 15:20 +1000
Message-ID	<dujd1nF7366U1@mid.individual.net> (permalink)
References	<87b8a1c6-e14c-47f7-9647-52f4ab874054@googlegroups.com>

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On 12/07/2016 3:50 AM, jonas.thornvall@gmail.com wrote:
> What kind of statistic law or mathematical conjecture  or is it even a physical law is violated by compression of random binary data?
>
> I only know that Shanon theorised it could not be done, but were there any proof?
>
> What is to say that you can not do it if the symbolic representation is richer than the symbolic represenatation of the dataset.
>
> Isn't it a fact that the set of squareroots actually depict numbers in a shorter way than their actual representation.
>
> Now the inpretator or program must know the rules. And i have very good rules to make it happen.
>

If you consider n bits of data, then there are 2^n different 
combinations. If your compression of the data is to be reversible, then 
your compression has to produce 2^n different bit sequences (of varying 
lengths, typically). If your compression produces some sequences that 
are shorter than n bits, then it has to produce others that are longer 
than n bits, otherwise it's impossible to have 2^n different sequences.

If some combinations are much more frequent than others, then you can 
make an overall gain by using shorter sequences for them, at the expense 
of longer sequences for the rarer combinations.

For random data, where each possible combination is equally likely, 
you're not going to come out ahead.

Sylvia.

Thread

Compression of random binary data jonas.thornvall@gmail.com - 2016-07-11 10:50 -0700
  Re: Compression of random binary data xxein1@att.net - 2016-07-11 13:12 -0700
  Re: Compression of random binary data Sergio <invalid@invalid.com> - 2016-07-11 15:42 -0500
  Re: Compression of random binary data Double-A <double-a3@hush.com> - 2016-07-11 13:58 -0700
    Re: Compression of random binary data Poutnik <poutnik4nntp@gmail.com> - 2016-07-11 23:12 +0200
  Re: Compression of random binary data "nuny@bid.nes" <Alien8752@gmail.com> - 2016-07-11 15:20 -0700
    Re: Compression of random binary data Sergio <invalid@invalid.com> - 2016-07-11 21:29 -0500
  Re: Compression of random binary data Lofty Goat <rlwatkins@gmail.com> - 2016-07-11 17:48 -0500
  Re: Compression of random binary data Fabian Russell <fb@zen.info> - 2016-07-11 23:39 +0000
    Re: One _never_ knows if data is truly random or not. Fabian Russell <fb@zen.info> - 2016-07-12 14:33 +0000
      Re: One _never_ knows if data is truly random or not. Poutnik <poutnik4nntp@gmail.com> - 2016-07-12 18:37 +0200
    Re: One _never_ knows if data is truly random or not. benj <benj@nobody.net> - 2016-07-12 19:26 -0400
  Re: Compression of random binary data Sylvia Else <sylvia@not.at.this.address> - 2016-07-12 15:20 +1000
    Re: Compression of random binary data Double-A <double-a3@hush.com> - 2016-07-12 13:29 -0700
      Re: Compression of random binary data Sylvia Else <sylvia@not.at.this.address> - 2016-07-13 16:29 +1000
  Re: Compression of random binary data Michael J. Strickland <michael06582@comcast.net> - 2016-07-14 00:54 -0400

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