Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!eu.feeder.erje.net!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: "osmium" Newsgroups: comp.programming Subject: Re: compressable data Date: Sat, 13 Jul 2013 10:58:57 -0500 Lines: 31 Message-ID: References: <319e8d2f-c636-4d3f-9820-00d28ed2a95d@googlegroups.com> <269ae1c1-e0bc-494b-ae89-ac6ec6952588@googlegroups.com> X-Trace: individual.net LLADyknakUx2DbOCbwaXGwFch/oGrlFDUsvTZ7ZxZYT9VKCqOu Cancel-Lock: sha1:jbvERPz2sf2Xmfc9stYrUki/pZs= X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2900.2180 X-RFC2646: Format=Flowed; Original X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 Xref: csiph.com comp.programming:3625 wrote: > On Tuesday, July 9, 2013 7:33:52 PM UTC+1, osmium wrote: >> wrote >> >> On the OPs question, I have to insert words into the question in order >> for >> it to have any meaning to me. Generate data. Generate *real* data? What >> is >> data? Is a journal article on some obscure branch of medicine or >> chemistry >> data? Is rap music data? By changing the definition of data, I change >> the >> compression ratio. But the OP, as I read it, wants it to be constant. I >> sense a problem. >> > With real data, it's very hard to define the entropy. But with random > data, > non-randomised by some rule, it can be relatively easy. So data which > consisted > of a discretised normal Markov model (so character i + 1 = character[i] + > (int) randgauss(), with wrap ) has a known entropy, and can be ideally > compressed > with a predictive algorithm with a single byte of state. It looks like we disagree on what the meaning of "data" is; to me, data has meaning. What I see you discussing is random bits. If there is no means of converting bits to something else, (by talking to a programmer, for example) it is just bits - no meaning - no data.