Den tisdag 12 juli 2016 kl. 17:12:01 UTC+2 skrev Steven D'Aprano: > On Wed, 13 Jul 2016 12:24 am, jonas.thornv...@gmail.com wrote: > > > Den måndag 11 juli 2016 kl. 20:38:51 UTC+2 skrev Steven D'Aprano: > >> On Tue, 12 Jul 2016 03:52 am, jonas.thornv...@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? > >> > >> The pigeon hole principle. If you have 100 pigeon holes, and 101 pigeons, > >> then clearly at least one pigeon hole must have two pigeons in it. > [...] > > But it seem your reasoning is based upon interpretation of the actual > > digits, bits and bytes value. > > Not at all. If you think that, you've misread my example. There's no > interpretation of the bytes: they are just 8-bit numbers from 0 to 255. You > cannot losslessly compress all 256 of them to just four 2-bit numbers. > > > > There could be different interpretation > > worlds of course you would have to chose one using digits, An > > interpretationworld here could be reading out different word lengths of > > the dataset and maybe a lookup table. > > Any lookup table you have counts as part of the compressed data. > > > > But it could also be arithmetic rules that magically recreate a number > > from a number of folds or difference of folds. > > Oh, sure, if you believe in magic, anything is possible. Just close your > eyes, click your heels together, and wish really, really hard. > > Suppose I could compress ANY random data, no matter what, down to 10% of the > original size. Okay, let's start with a million bits of data. Compress it > down to 100,000 bits. > > But I believe that I can compress *anything*, any random collection of data. > Okay, let me compress it again. Now I have 10,000 bits. > > Compress it again. Now I have 1,000 bits. > > Compress it again. Now I have 100 bits. > > Compress it again. Now I have 10 bits. > > Compress it again. Now I have 1 bit, either a 0 or a 1. > > > Can you not see how absurd this is? I have claimed that I can take *any* > random set of data, and by compressing it again and again and again, > compress it down to ONE BIT, either a 0 or a 1, WITHOUT LOSS. Somehow I > have to take that 0 bit and uncompress it back to the Complete Works Of > William Shakespeare, and *also* uncompress it back to the recent Deadpool > movie, AND uncompress it back to last year's Ant Man movie, AND uncompress > it back to some funny picture of a cat. > > How can I possibly know which of the billions and billions of different > files this 0 bit represents? > > If you pass me a 0 bit, and say "uncompress this", and I get The Lord Of The > Rings novels, and then you pass me another 0 bit, and I uncompress it and > get The Hobbit, well, how did I tell the two bits apart? They're both zero. > > > > The alternative is to say, it doesn't matter how clever you are, you can't > compress *everything*. There are some things that simply won't compress. > Eventually you get something no longer compresses. If you could compress > EVERYTHING, then you could compress the compressed data, and compress the > compressed-compressed data, and so on, until you've got only a single bit. > And that is ridiculous. > > > > -- > Steven > “Cheer up,” they said, “things could be worse.” So I cheered up, and sure > enough, things got worse.
No it is only compressible down to a limit given by the algorithm. -- https://mail.python.org/mailman/listinfo/python-list
