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| References | (1 earlier) <mailman.1825.1383159257.18130.python-list@python.org> <0f857f7f-5947-4b3a-805d-0e9b888dfd48@googlegroups.com> <l4rm20$omr$1@ger.gmane.org> <CAN1F8qU_zJFitGzagQSJqdmEh5h=40ss=ToUcTdC3T783PH10A@mail.gmail.com> <20131030180139.7080b190@bigbox.christie.dr> |
|---|---|
| Date | 2013-10-31 10:41 +1100 |
| Subject | Re: Algorithm that makes maximum compression of completly diffused data. |
| From | Chris Angelico <rosuav@gmail.com> |
| Newsgroups | comp.lang.python |
| Message-ID | <mailman.1862.1383176481.18130.python-list@python.org> (permalink) |
On Thu, Oct 31, 2013 at 10:01 AM, Tim Chase
<python.list@tim.thechases.com> wrote:
> On 2013-10-30 21:30, Joshua Landau wrote:
>> started talking about compressing *random data*
>
> If it's truly random bytes, as long as you don't need *the same*
> random data, you can compress it quite easily. Lossy compression is
> acceptable for images, so why not random files? :-)
Maybe. But what if it's not truly random, but only pseudo-random?
# create a file full of random data
import random
seed = random.getrandbits(32)
length = random.getrandbits(16) # in four-byte units
random.seed(seed)
inname = "random.txt"
namez = inname + '.rnz'
with open(inname, "wb") as bigfile:
for _ in range(length):
bigfile.write(random.getrandbits(32).to_bytes(4,"big"))
# compress that file
with open(namez, "wb") as smallfile:
smallfile.write(seed.to_bytes(4,"big"))
smallfile.write(length.to_bytes(4,"big"))
# uncompress it
with open(namez, "rb") as f:
seed = int.from_bytes(f.read(4),"big")
length = int.from_bytes(f.read(4),"big")
random.seed(seed)
with open("out_" + inname, "wb") as bigfile:
for _ in range(length):
bigfile.write(random.getrandbits(32).to_bytes(4,"big"))
Voila! Very impressive compression ratio, and exploits the very
randomness of the data!
ChrisA
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Algorithm that makes maximum compression of completly diffused data. jonas.thornvall@gmail.com - 2013-10-30 11:21 -0700
Re: Algorithm that makes maximum compression of completly diffused data. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-30 18:53 +0000
Re: Algorithm that makes maximum compression of completly diffused data. jonas.thornvall@gmail.com - 2013-10-30 12:01 -0700
Re: Algorithm that makes maximum compression of completly diffused data. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-30 19:18 +0000
Re: Algorithm that makes maximum compression of completly diffused data. jonas.thornvall@gmail.com - 2013-10-30 12:22 -0700
Re: Algorithm that makes maximum compression of completly diffused data. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-30 19:31 +0000
Re: Algorithm that makes maximum compression of completly diffused data. jonas.thornvall@gmail.com - 2013-10-30 12:23 -0700
Re: Algorithm that makes maximum compression of completly diffused data. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-30 19:35 +0000
Re: Algorithm that makes maximum compression of completly diffused data. Ethan Furman <ethan@stoneleaf.us> - 2013-11-02 21:26 -0700
Re: Algorithm that makes maximum compression of completly diffused data. Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-10-30 20:28 +0100
Re: Algorithm that makes maximum compression of completly diffused data. Joshua Landau <joshua@landau.ws> - 2013-10-30 21:30 +0000
Re: Algorithm that makes maximum compression of completly diffused data. rusi <rustompmody@gmail.com> - 2013-10-31 05:54 -0700
Re: Algorithm that makes maximum compression of completly diffused data. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2013-10-30 21:52 +0000
Re: Algorithm that makes maximum compression of completly diffused data. Tim Chase <python.list@tim.thechases.com> - 2013-10-30 18:01 -0500
Re: Algorithm that makes maximum compression of completly diffused data. Chris Angelico <rosuav@gmail.com> - 2013-10-31 10:41 +1100
Re: Algorithm that makes maximum compression of completly diffused data. Dan Stromberg <drsalists@gmail.com> - 2013-10-30 12:29 -0700
Re: Algorithm that makes maximum compression of completly diffused data. Tim Delaney <timothy.c.delaney@gmail.com> - 2013-10-31 06:35 +1100
Re: Algorithm that makes maximum compression of completly diffused data. jonas.thornvall@gmail.com - 2013-10-30 12:47 -0700
Re: Algorithm that makes maximum compression of completly diffused data. Modulok <modulok@gmail.com> - 2013-10-30 13:46 -0600
Re: Algorithm that makes maximum compression of completly diffused data. jonas.thornvall@gmail.com - 2013-10-30 12:47 -0700
Re: Algorithm that makes maximum compression of completly diffused data. Gene Heskett <gheskett@wdtv.com> - 2013-10-30 16:32 -0400
Re: Algorithm that makes maximum compression of completly diffused data. Tim Roberts <timr@probo.com> - 2013-11-02 14:31 -0700
Re: Algorithm that makes maximum compression of completly diffused data. Mark Janssen <dreamingforward@gmail.com> - 2013-11-02 14:37 -0700
Re: Algorithm that makes maximum compression of completly diffused data. Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-11-03 03:17 +0000
Re: Algorithm that makes maximum compression of completly diffused data. Chris Angelico <rosuav@gmail.com> - 2013-11-03 15:10 +1100
Re: Algorithm that makes maximum compression of completly diffused data. Joshua Landau <joshua@landau.ws> - 2013-11-03 15:34 +0000
Re: Algorithm that makes maximum compression of completly diffused data. Joshua Landau <joshua@landau.ws> - 2013-11-03 15:51 +0000
Re: Algorithm that makes maximum compression of completly diffused data. Mark Janssen <dreamingforward@gmail.com> - 2013-11-03 19:40 -0800
Re: Algorithm that makes maximum compression of completly diffused data. Tim Chase <python.list@tim.thechases.com> - 2013-11-04 07:08 -0600
Re: Algorithm that makes maximum compression of completly diffused data. jonas.thornvall@gmail.com - 2013-11-04 05:53 -0800
Re: Algorithm that makes maximum compression of completly diffused data. jonas.thornvall@gmail.com - 2013-11-04 06:00 -0800
Re: Algorithm that makes maximum compression of completly diffused
data. Dave Angel <davea@davea.name> - 2013-11-04 08:27 -0600
Re: Algorithm that makes maximum compression of completly diffused data. rusi <rustompmody@gmail.com> - 2013-11-04 06:46 -0800
Re: Algorithm that makes maximum compression of completly diffused data. jonas.thornvall@gmail.com - 2013-11-04 14:34 -0800
Re: Algorithm that makes maximum compression of completly diffused
data. Dave Angel <davea@davea.name> - 2013-11-04 19:29 -0600
Re: Algorithm that makes maximum compression of completly diffused data. Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-11-05 04:33 +0000
Re: Algorithm that makes maximum compression of completly diffused data. Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-11-05 04:36 +0000
Re: Algorithm that makes maximum compression of completly diffused data. Tim Roberts <timr@probo.com> - 2013-11-07 00:05 -0800
Re: Algorithm that makes maximum compression of completly diffused data. Mark Janssen <dreamingforward@gmail.com> - 2013-11-07 10:59 -0800
Re: Algorithm that makes maximum compression of completly diffused data. Tim Roberts <timr@probo.com> - 2013-11-07 11:22 -0800
Re: Algorithm that makes maximum compression of completly diffused data. Chris Angelico <rosuav@gmail.com> - 2013-11-08 09:26 +1100
Re: Algorithm that makes maximum compression of completly diffused data. jonas.thornvall@gmail.com - 2013-11-07 18:05 -0800
Re: Algorithm that makes maximum compression of completly diffused data. Chris Angelico <rosuav@gmail.com> - 2013-11-08 13:17 +1100
Re: Algorithm that makes maximum compression of completly diffused data. jonas.thornvall@gmail.com - 2013-11-07 18:25 -0800
Re: Algorithm that makes maximum compression of completly diffused data. rusi <rustompmody@gmail.com> - 2013-11-07 18:36 -0800
Re: Algorithm that makes maximum compression of completly diffused data. Chris Angelico <rosuav@gmail.com> - 2013-11-08 13:36 +1100
Re: Algorithm that makes maximum compression of completly diffused data. Mark Janssen <dreamingforward@gmail.com> - 2013-11-07 18:43 -0800
Re: Algorithm that makes maximum compression of completly diffused data. Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-11-08 04:47 +0000
Re: Algorithm that makes maximum compression of completly diffused data. Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2013-11-08 20:09 +1300
Re: Algorithm that makes maximum compression of completly diffused data. Chris Angelico <rosuav@gmail.com> - 2013-11-08 18:21 +1100
Re: Algorithm that makes maximum compression of completly diffused data. jonas.thornvall@gmail.com - 2013-11-08 07:48 -0800
Re: Algorithm that makes maximum compression of completly diffused data. rusi <rustompmody@gmail.com> - 2013-11-08 07:57 -0800
Re: Algorithm that makes maximum compression of completly diffused data. Ian Kelly <ian.g.kelly@gmail.com> - 2013-11-08 11:48 -0700
Re: Algorithm that makes maximum compression of completly diffused data. "R. Michael Weylandt <michael.weylandt@gmail.com>" <michael.weylandt@gmail.com> - 2013-11-07 21:43 -0500
Re: Algorithm that makes maximum compression of completly diffused data. Chris Angelico <rosuav@gmail.com> - 2013-11-08 14:05 +1100
Re: Algorithm that makes maximum compression of completly diffused data. Roy Smith <roy@panix.com> - 2013-11-07 22:08 -0500
Re: Algorithm that makes maximum compression of completly diffused data. Chris Angelico <rosuav@gmail.com> - 2013-11-08 14:24 +1100
Re: Algorithm that makes maximum compression of completly diffused data. "R. Michael Weylandt <michael.weylandt@gmail.com>" <michael.weylandt@gmail.com> - 2013-11-07 23:05 -0500
Re: Algorithm that makes maximum compression of completly diffused data. Chris Angelico <rosuav@gmail.com> - 2013-11-08 15:06 +1100
Re: Algorithm that makes maximum compression of completly diffused
data. Dave Angel <davea@davea.name> - 2013-11-07 22:12 -0600
Re: Algorithm that makes maximum compression of completly diffused data. Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-11-08 05:32 +0000
Re: Algorithm that makes maximum compression of completly diffused data. Mark Janssen <dreamingforward@gmail.com> - 2013-11-07 18:24 -0800
Re: Algorithm that makes maximum compression of completly diffused data. Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2013-11-08 20:16 +1300
Re: Algorithm that makes maximum compression of completly diffused data. Chris Angelico <rosuav@gmail.com> - 2013-11-08 13:27 +1100
Re: Algorithm that makes maximum compression of completly diffused data. Ethan Furman <ethan@stoneleaf.us> - 2013-11-02 21:26 -0700
Re: Algorithm that makes maximum compression of completly diffused data. Mark Janssen <dreamingforward@gmail.com> - 2013-11-02 23:09 -0700
Re: Algorithm that makes maximum compression of completly diffused data. Michael Torrie <torriem@gmail.com> - 2013-11-03 08:14 -0700
Re: Algorithm that makes maximum compression of completly diffused data. jonas.thornvall@gmail.com - 2013-10-30 12:49 -0700
Re: Algorithm that makes maximum compression of completly diffused data. Grant Edwards <invalid@invalid.invalid> - 2013-10-30 21:18 +0000
Re: Algorithm that makes maximum compression of completly diffused data. Mark Janssen <dreamingforward@gmail.com> - 2013-10-30 14:26 -0700
Re: Algorithm that makes maximum compression of completly diffused data. Dave Angel <davea@davea.name> - 2013-10-31 03:22 +0000
Re: Algorithm that makes maximum compression of completly diffused data. Gene Heskett <gheskett@wdtv.com> - 2013-11-03 04:50 -0500
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