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Education Science

1.7 Billion Digits Of Pi On CD 202

Posted by timothy from the amuse-enemies-baffle-friends dept.
H0ek writes "Not that there is any use for this whatsoever, but there is a torrent available for 1.7 billion digits of pi on a CD. The data is everything after the '3.' on one line, bzipped. There are a couple of the Cygwin tools on the disk as well as source for a small search tool (because grep just didn't cut it this time). Inside the ISO there's links to the source of the data, in case you want the rest of the 4.2 billion digits available. Wear your geek badge with pride! Be the first kid on your block to have the entire set!"
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1.7 Billion Digits Of Pi On CD More

1.7 Billion Digits Of Pi On CD

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  • On a T-Shirt (Score:4, Funny)

    by stu_coates ( 156061 ) on Wednesday January 26, 2005 @01:09PM (#11482457)
    ...and it's available on a T-Shirt from ThinkGeek... only in size XXXXXXXL. ;-)
  • You could probably get another several billion digits on there!

  • pi memorization contests (Score:5, Funny)

    by gothzilla ( 676407 ) on Wednesday January 26, 2005 @01:13PM (#11482505)
    Me and a friend of mine had a contest once to see who could memorize PI to the most number of decimals. He beat me badly. Needless to say he became a successful wealthy programmer while I still fix pc's for a living.
    Never underestimate the power of PI. :)
  • one down, fifty thousand to go. the torrents-instead-of-mirrors-in-/.-news-items revolution has begun!

  • No 3? (Score:5, Funny)

    by SilkBD ( 533537 ) on Wednesday January 26, 2005 @01:14PM (#11482518) Homepage
    The data is everything after the '3.' on one line, bzipped.

    What? They couldn't fit the '3' on the disc???

    • probably because its stored not as text but as a number, thus would you rather store it as a floating point, or as a really large whole number and throw away the decimal.. I thought so.

    • Re:No 3? (Score:3, Funny)

      by stienman ( 51024 )
      What? They couldn't fit the '3' on the disc???

      Duh! It's 30 times larger than the next digit, which is 2.5 times bigger than the next digit, etc.

      The biggest savings occurs by chopping off the "3."

      -Adam
    • The 3 is trivial. The proof is left as an exercise for the reader.

      - shazow
    • If they were slick they would have printed the "3." on the label of the CD - thus 'techincally' including it.

  • Useless? (Score:4, Interesting)

    by Xaroth ( 67516 ) on Wednesday January 26, 2005 @01:14PM (#11482525) Homepage
    "Not that there is any use for this whatsoever..."

    I'm not so sure. Given that there are all sorts of interesting things about the number (a quick google search turned up this [piworld.de] as an example), having a CD with the first couple billion digits could be useful for anyone playing around with statistical analysis of it.
    • And a statistical analysis of the digits of Pi would be useful because? :-)

    • Re:Useless? (Score:4, Insightful)

      by Zocalo ( 252965 ) on Wednesday January 26, 2005 @01:52PM (#11483065) Homepage
      Interesting, and a step beyond just using Pi (or e, or...) as a source of sequences of random numbers but I can't help but feel that there is an element of "Bible Code Syndrome" here. There seems to be a similar obsession with finding a pattern in Pi as some have with finding messages from God in the Bible. What happens if we do a statistical analysis of every nth digit? What happens if we do an analysis of all the odd digits? Or even digits? What if we reverse the sequence and try again? Try again in other number bases?

      It's an infinite data set; apply an infinite number of methods of analysis and the odds are good that some of them will give results that might be considered meaningful. Even if you do find something, whether it's a something profound about the structure of the universe or even a message from God, you then have another problem. How are you then supposed to prove that it's not a statistical fluke keeping in mind that an infinite random data string will contain within itself every possible sequence?

      • Better yet, since pi only contains a countable number of infinite digits, and there are uncountably infinite numbers of problems (see any decent book on theory of computing), the digits of pi most likely solve an infinite number of problems. Of course, since we can only describe a finite number of problems (in a finite amount of time), there are far fewer of these. The digits of pi do solve, for example, the problem of the ratio of a circle's circumference to its diameter. Of course, the question we're real

      • Re:Useless? (Score:3, Interesting)

        by museumpeace ( 735109 )
        Far be it from me to step in a pile of God doodoo, especially on /. but...
        There is a pattern of sorts in the digits of Pi. Providing you don't mind working in hexadecimal, [why that base and no other?...any math PhD's in the audiance?] formula 29 on this page [wolfram.com] gives you a way to calculate any arbitrary digit of Pi without running a series calculation up to that digit's precision. If a formula for any digit, with independence from all other digits doesn't stretch the definition too much, I'll call it a patt

        • Re:Useless? (Score:3, Insightful)

          by Zocalo ( 252965 )
          Yeah, I'd come across that formula before which is where my reference to trying other numeric bases came from. Similarly the reference to the message from God in Pi was from "Contact" by Carl Sagan (the book, rather than the film, as well as a nice link back to the Bible Code. And that's where I have a problem; the usual approach is more akin to looking for a hidden message rather than finding a reason *why*.

          My own personal view is that few, if any, of these universal constants, whether mathematical lik

          • If I thought about it much, and I haven't since my grad school days, I'd pretty much agree with your stance on whether you even need to invoke an author of creation when, for all we know:
            1. the slightest alteration of the constants and the relationships that physics has found would cause all existance to wink out in a puff of impossible inconsistency [we have no choice of worlds and to talk of others is pointless]
            2. Yet there may be equally inescapable laws or logic that demand a univers must exist [of this I
        • I too am of the opinion that anything which can be algorithmically derived must have some sort of pattern. The fact that there is no such thing as a true random number generator gives us an limit we can approach asymptotically, os we know there is no finite limit to the accuracy of algorithms, only a limit to their applicability.

          Sometimes I think God created us just to appreciate his cool handiwork here in the universe. :-)
      • The concept of a message in pi is part of the plot of "Contact", a novel by Carl Sagan about SETI receiving a signal from an extraterrestrial intelligence. The aliens say that someone/something embedded a message in pi. The questions brought up by this are of course: Who? and How?

      • Re:Useless? (Score:3, Funny)

        by Alsee ( 515537 )
        What if we reverse the sequence and try again?

        During step two you get laid.

        -
      • There seems to be a similar obsession with finding a pattern in Pi as some have with finding messages from God in the Bible.

        Although you probably meant to imply something about hidden and cryptographic to that phrase, if you didn't, you might be surprised to know that believers understand the entire Bible to be a message from God in plain language. :)

    • Re:Useless? (Score:3, Insightful)

      by illuvata ( 677144 )
      Why wouldn't they just generate it themself? For most people, downloading an ISO and extracting the archive would be slower than just to use something like this [computation.free.fr].

      • Re:Useless? (Score:3, Funny)

        by gstoddart ( 321705 )
        Why wouldn't they just generate it themself? For most people, downloading an ISO and extracting the archive would be slower than just to use something like this.


        Oh, man, you just spoiled this guys whole business model.

        Guess it's back to underpants.

    • IIRC, Intel has used the billions of digits of PI to test their hardware for errors. So yeah...a billion digits of PI could be useful.

  • Alas, firewalls... (Score:2, Interesting)

    by CAlworth1 ( 518119 )
    While there is probably nothing useful that I could do with this file, there is also no way for me to be able to get it, even if I had something to do with it - One of the wonderful things about going college in the day and age where it is bad to share information is that bitTorrent is not allowed.... mirror of pi anyone?

    Having said that, it seems interesting to be asking, literally, for a mirror of the real world - as numbers go, this is pretty real.

  • Unlikely! (Score:3, Insightful)

    by JaxWeb ( 715417 ) on Wednesday January 26, 2005 @01:18PM (#11482588) Homepage Journal
    Be the first kid on your block to have the entire set!

    You're unlikely to be the first kid on the block to have the whole set of Pie digits...
    • You're unlikely to be the first kid on the block to have the whole set of Pie digits...

      You never know, he might get the whole set of PIE digits, but he definitely wouldn't get the whole set of PI digits.

  • Not yet, I'll wait a few months... (Score:5, Funny)

    by Rahga ( 13479 ) on Wednesday January 26, 2005 @01:20PM (#11482611) Journal
    I figure the director's cut on DVD will include even more content.

  • Shouldn't compress well (Score:5, Insightful)

    by crow ( 16139 ) on Wednesday January 26, 2005 @01:20PM (#11482624) Homepage Journal
    At first, I was thrown off by the idea of compressing something like pi, as it shouldn't compress. The answer is that they're storing ASCII decimal digits, which require less than 4 bits per number, instead of 8. So you should get at least a 50% compression ratio, which would be 850 million bytes. But it's actually 3.something bits of information per byte, so they're able to fit it on a CD. I would be surprised if bzip could do any better than that.

    • Re:Shouldn't compress well (Score:5, Interesting)

      by slamb ( 119285 ) * on Wednesday January 26, 2005 @02:05PM (#11483268) Homepage
      At first, I was thrown off by the idea of compressing something like pi, as it shouldn't compress. The answer is that they're storing ASCII decimal digits, which require less than 4 bits per number, instead of 8. So you should get at least a 50% compression ratio, which would be 850 million bytes. But it's actually 3.something bits of information per byte, so they're able to fit it on a CD. I would be surprised if bzip could do any better than that.

      I had the same thought. To put it in dirt-simple terms, they're only using 10 out of the 256 possible values in every byte, due to the ASCII encoding. This is how bzip2 is able to find any redundancy; pi itself has none.[*]

      So the best compression ratio (just compressed size/uncompressed size, right? so lower is better) is ln(10) / ln(256) = 41.5%. On a 700 MiB CD with no filesystem and nothing but pi, this means 700 * 2^20 / ln(256) * ln(10) = 1.77 billion digits (1767655840, with almost room for one more).

      You'd do better than bzip2 by just using fixed blocks of N bytes to represent M digits. (Larger choices would get you closer to that best ratio; lower choices would less work to decode each block, which might make seeking more practical and reduce memory requirements.) This would be superior to bzip2 in that it'd get somewhat better compression, use a lot less CPU time, and be seekable. You could encode and decode with a one-line Perl script.

      [*] - I suppose you could simply include the algorithm they used to generate the digits...but it'd take a long time to run, negating the whole point of putting pi on a CD.

      • Right... that was my first thought -- why not just use a compact encoding? It would be more easily seekable, anyway. But then I realized that 2^a != 10^b (for any integer a and b), so there's bound to be some loss. But of course it's not so bad anyway. Blocks of 10 bits pack three digits, with a waste of 0.034 bits = 0.34%. The optimum block size (for numbers under 4k) seems to be 2136 bytes, but if you go for 2048 bytes for CD-reading convenience, you can pack 616 digits. You waste almost a third of a bit
        • Whoops. Thinko there, forgot to convert bits to bytes. You can pack 616 digits into 2048 bits. There would, of course, have to be 8 of those to fill out a data-mode CD sector. If you wanted to use the whole sector as one block, it would hold 4932 digits, at an efficiency good enough that there's less than one bit wasted on the entire CD (and therefore you couldn't gain anything by using a different encoding anyway).
    • I would be surprised if bzip could do any better than that.

      Out of curiosity--

      Bzip could could only improve on that if it found some repeating data the stream, right? Any improvement beyond the 50% compression ratio would be pretty revolutionary...
    • Assuming that the ASCII digits of pi are evenly distributed between '0' and '9', then you should have log2(10) = 3.322 bits per digit. At 3.322 bits per digit and 700MiB (5872025600 bits at 8 bits per byte) we should have about 1,767,655,841
      digits. Assuming that they're publishing exactly 1.7 Billion digits, they're within 3.8% of ideal compression, assuming an eactly even distribution of digits.

      Where it gets interesting is if there's NOT an even distribution of digits (which I don't believe is actuall

  • Wow. (Score:3, Funny)

    by Anonymous Coward on Wednesday January 26, 2005 @01:23PM (#11482649)
    If that torrent gets past 5 seeders, I will EAT A BRICK.
    How about just linking to the software included on the cd and not the whole cd proper?
    I'll say this: the BAD thing about BitTorrent is not the fact that 80% of its use is illegal, rather that it lowers the barrier of entry to hosting huge (and incidentally useless, in this case) files from random hole-in-the-wall ISPs.

    I'll take back everything I said if that's a huge torrent of porn disguised as a PI cd.

    • Re:Wow. (Score:2, Interesting)

      by H0ek ( 86256 )
      Less than two hours after the posting of the article to the public it's hit 6 seeders. Let me present to you your BRICK.

      This from a site on a 500MHz P3 sitting on a little cable modem on a public utility style ISP providing 100KB/s upload speed. I love BitTorrent.

    • Re:Wow. (Score:3, Funny)

      by Alsee ( 515537 )
      I'll take back everything I said if that's a huge torrent of porn disguised as a PI cd.

      Dude! 1.7 BILLION digits of Pi *is* geek porn.

      -

  • Mathematical Music (Score:5, Funny)

    by Marillion ( 33728 ) <ericbardes@NOsPaM.gmail.com> on Wednesday January 26, 2005 @01:27PM (#11482698)
    Burn it as an audio CD. The static will still sound better than most of the recently released music.

    • You're a genius! (Score:4, Funny)

      by FiloEleven ( 602040 ) on Wednesday January 26, 2005 @03:19PM (#11484232)
      Since nothing is going horribly wrong at work today, I took your advice. You will not believe what is encoded in the sequence!

      Most of it is awful noise, but after the first two or three minutes it ceases being pure white noise and you get some interesting texture. At this point, I turned up the volume a bit and kept surfing Slashdot. Until my mind was blown.

      Right around 7 minutes 6 seconds into the track, the textures resolve into a whispery voice. I know this sounds nuts, and I wouldn't believe it either if I hadn't heard it myself. There's still a lot of fuzz, but ifyou listen carefully you can make out some of what it says:

      "...four simultaneous [unintelligible] four hour days...[unintelligible]...rotation of the earth"
      "ineffable truth and wisdom"
      "four corner [unintelligible] metamorphic human"

      This stuff goes on and on, but I need to clean up the audio to understand everything! Does anyone have recommendations for heuristic filtering software? This is absolutely amazing. I wonder what it all means?
    • I was going to put the human genome and Pi onto my iPod, but that would mean that I'd have to delete my collection of [insert reference to crap pop music here]...
    • and more intersting than the crap I read here, and incidentally, more interesting than what I am writing now.

  • Who uses PI? (Score:2, Insightful)

    by vettemph ( 540399 )
    I use pie all the time in an Engineering lab. typically out to 3 or 4 decimals. Does anyone NEED to use PI to a greater level of accuracy? If so, what application and how many decimal places do you require?

  • Woo Hoo! (Score:3, Funny)

    by forty-2 ( 145915 ) on Wednesday January 26, 2005 @01:37PM (#11482804)
    Now I can finally find my phone number in pi.

  • Go to pi.com! ;-) (Score:5, Interesting)

    by xmas2003 ( 739875 ) * on Wednesday January 26, 2005 @01:54PM (#11483100) Homepage
    http://3.14159265358979323846264338327950288419716 9399375105820974944592.com/ [1415926535...944592.com] which is the longest you can do in DNS currently ...

  • I've got a bunch of digits of pi (Score:5, Funny)

    by Xtifr ( 1323 ) on Wednesday January 26, 2005 @02:07PM (#11483305) Homepage
    Since pi is infinite and irrational, I'm pretty sure that the data on every CD I own appears somewhere in pi. So, can I distribute these too? :)
    • I'm pretty sure that the data on every CD I own appears somewhere in pi.

      Oh great, just what I need. Now every time I see a circle, I'll be reminded that pi contains Britney Spears' Greatest Hits. Bastard.

      On the plus side, it also contains every snide remark made about her. Including this one.
    • Since pi is infinite and irrational, I'm pretty sure that the data on every CD I own appears somewhere in pi. So, can I distribute these too? :)

      Cute concept.

      Of course you mean that the number of digits in pi is infinite. We both know pi isn't infinite since it's greater than three and less than four. Of course all irrational numbers have an infinite number of digits, so it works better to say, "Since pi is irrational, etc".

      While I don't know about pi, an irrational number does not have to contain ev

    • Don't think that's true for pi. It might be true for a normal number [wolfram.com]. You can find a normal number by picking a random point on a ruler and measuring its location to an infinite accuracy. Good luck on achieving the infinite accuracy bit though.
    • "No judge, that really wasnt a song i was trading, that was just a snapshot of a part of pi.. i love math"
  • 1.7 billion digits of pi on a CD.

    And if you have trouble visualizing what Pi calculated to 1.7billion digits, the CD conveniently comes in the shape of a near-perfect circle for reference.

  • Torrent (Score:5, Funny)

    by bcmm ( 768152 ) on Wednesday January 26, 2005 @02:25PM (#11483570)
    As this is actually an article about a torrent, I feel that it is legitimate and on-topic to say:
    Please stop leaching. You should open at least port 6881 for incoming connections, and leave your bittorrent client open until you have uploaded at least as much as you have downloaded. It's only fair.
    Thank you.

    (I assume that you are all actually downloading this and not just laughing about it, right?)

  • Hidden messages (Score:2, Informative)

    by jsveiga ( 465473 )
    If all you want to do is search for mystic stuff inside the number, you don't need the CD with its measly 1.7bi digits.

    Save your bandwidth and just go here [nersc.gov] to search within 4bi digits.

  • Expansion Pack (Score:4, Funny)

    by MankyD ( 567984 ) on Wednesday January 26, 2005 @02:44PM (#11483807) Homepage
    The '3' will be included in the expansion pack, slated for release in early 2006.

  • Compressing Pi (Score:2, Insightful)

    by rdwald ( 831442 )
    The data is everything after the '3.' on one line, bzipped.

    So, in order to reduce the space on the CD, they bzipped it? I could see that helping for the search code, etc., but for pi itself, isn't it impossible to represent it in less space than it already takes without actually using a mathematical formula which defines pi? I would think the only way to actually save space would be to use some non-ASCII encoding scheme such that each byte could hold two digits, not one. Or encode it in hexadecimal, and

    • Re:Compressing Pi (Score:3, Informative)

      by MankyD ( 567984 )
      If each digit is was stored as ascii, you could use a Huffman code (the basic zip encoding) to shrink it down. This returns a result much like you suggested. If for those not familiar with Huffman Codes, I'll give a quick and dirty summary:

      Say each char takes 8 bytes but, in this case, you're only using 10 chars, so you don't need 8 bytes to represent it all. Huffman codes do a quick count of character frequencies and create tree of shorter bit representations for each character. Characters that have
    • Of course you can compress it. Only a few bits of ASCII are used as Pi only consists of digits.
  • Why only 1.7B digits? You can fit all the digits on one CD, without even writing to the disc: just divide the circumference of the CD by its diameter! That's (theoretically) infinite compression, better than bzip2.
    • In theory, yes. But unless you can find a perfectly circular CD, then even your ideally accurate measurements will be off by a large factor.
      • Which raises the question of how they compute it in the first place. I've always wondered that. The only way that I've seen that makes sense is the ever-shrinking triangle method, where successively smaller triangles are used to compute estimates of the value of pi.
    • This is similar (and similarly flawed) to the following riddle:

      Ford Prefect, the space alien, arrived on Earth one day. Intrigued by the blandness of Earth, he wanted to document the sum total of mankinds knowledge for the amusement of his friends back home. The only problem was that, though ridiculously tiny by galactic standards, humans had created enough bad fiction that the databanks on Ford Prefect's ship would be unable to carry it back. Ford thought for a moment, then found a solution: He would get

  • Algorithm (Score:2, Interesting)

    by FullMetalAlchemist ( 811118 )
    Does anyone have a link to the algorithm where one can calculate the digits of pi at any given position without knowing the result from the preceding digits?

  • Applicable poem (Score:2, Informative)

    by H0ek ( 86256 )
    The nifty thing about sharing links like this is you get fun mail, like this poem from a friend:

    Now I will a rhyme construct
    By chosen words the youth instruct
    Cunningly devised endeavour
    Con it and remember ever
    Widths in circle, here you see
    Sketched out in strange obscurity

    I might just have to memorize it. ;-)
  • The first one to ask for a fork gets Pi in his face.

  • PI server (Score:2, Interesting)

    by JVolkman ( 771436 )
    http://3.14159265358979323846264338327950288419716 9399375105820974944592.jp [1415926535...4944592.jp]
    I believe this server keeps sending digits of PI indefinitely (most likely using the fun Nth-digit-of-PI formula). It's already a slow site, and will probably be slashdotted quickly. (This is not a dupe of the .com posted earlier)
  • I want 1.7 billion digits of Pi on the wall [99-bottles-of-beer.net].

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