Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!uunet!garfield!matthew1 From: matthew1@garfield.cs.mun.ca (Matthew J. Newhook) Newsgroups: comp.compression Subject: Re: IP gnitaluclaC rof margorP (Was Re: Program for Calculating PI) Message-ID: <1991Apr11.022122.26142@garfield.cs.mun.ca> Date: 11 Apr 91 02:21:22 GMT References: <28916@dime.cs.umass.edu> <24380001@hpdmd48.boi.hp.com> Organization: CS Department, Memorial University of Newfoundland Lines: 44 otto@tukki.jyu.fi (Otto J. Makela) writes: >In article jpc@fct.unl.pt (Jose Pina Coelho) writes: > Won't work, PI is uncompressible, one billion digits won't fit in a > diskette. On the other hand, if you run the program on the cray you'll > have PI in the cray in a lot less time (after all, diskettes are slow). >I wouldn't be so sure about it. Pi is globally high-entropy but locally >displays repeated sequences etc., which should make it compressable. Of >course it doesn't compress very much, but it does compress some. >-- I'd be inclined to say that you can compress pi by a considerable amount. Ok... Assume 8 bits per byte. Storing, say, 1000 digits of pi would therefore take up 8008 bits (1000 * 8 + 1 * 8, for the . in 3.14...). Since we only get characters from 0-9 ignoring the . then we can encode any digit in 4 bits. Like so... 0000 - 0 0001 - 1 0010 - 2 0011 - 3 0100 - 4 0101 - 5 0110 - 6 0111 - 7 1000 - 8 1001 - 9 So compression would be 50 %. Not too bad. Of course this is just for pi.... but I think I've made my point. > /* * * Otto J. Makela * * * * * * * * * * * * * * * * * * */ > /* Phone: +358 41 613 847, BBS: +358 41 211 562 (USR HST/V.32, 24h/d) */ > /* Mail: Kauppakatu 1 B 18, SF-40100 Jyvaskyla, Finland, EUROPE */ >/* * * Computers Rule 01001111 01001011 * * * * * * * * * * * * * * * * */ Matthew Newhook -- ----------------matthew1@garfield.cs.mun.ca "Living in the limelight; the universal dream for those who wish to seem. Those who wish to be must put aside the alienation, get on with the facination, the real relation, the underlying theme" - Rush