1.7 Billion Digits Of Pi On CD

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!"

Comments

On a T-Shirt

[stu_coates]

...and it's available on a T-Shirt from ThinkGeek... only in size XXXXXXXL. ;-)

pi memorization contests

[gothzilla]

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. :)

Re:pi memorization contests

[miTcixelsyD]

Needless to say, he's living at home with Mom and you're actually dating women! :-p

No 3?

[SilkBD]

The data is everything after the '3.' on one line, bzipped.

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

Useless?

[Xaroth]

"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 as an example), having a CD with the first couple billion digits could be useful for anyone playing around with statistical analysis of it.

Re:Useless?

[Zocalo]

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?

Re:Useless?

[illuvata]

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.

Not yet, I'll wait a few months...

[Rahga]

I figure the director's cut on DVD will include even more content.

Shouldn't compress well

[crow]

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

[slamb]

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.

Wow.

[Anonymous Coward]

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.

Mathematical Music

[Marillion]

Burn it as an audio CD. The static will still sound better than most of the recently released music.

Woo Hoo!

[forty-2]

Now I can finally find my phone number in pi.

Re:Woo Hoo!

[stienman]

You could do that before:
PI Phone Number Search Engine

-Adam

Go to pi.com! ;-)

[xmas2003]

http://3.14159265358979323846264338327950288419716 9399375105820974944592.com/ which is the longest you can do in DNS currently ...

Re:Who uses PI?

[Daniel Dvorkin]

Our microscopic image processing software uses pi to considerable precision. This is, I admit, a pretty specialized application.

I've got a bunch of digits of pi

[Xtifr]

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? :)

1.7 billion digits of pi on a CD, WITH A BONUS!

[EnronHaliburton2004]

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

[bcmm]

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?)

Re:Why not DVD?

[m_chan]

Spoiler ahead:

The last digit is 4.

I also wrote a compression algorithm that will get you all the digits in 11 characters. Feel free to share with your friends:

0123456789.

Expansion Pack

[MankyD]

The '3' will be included in the expansion pack, slated for release in early 2006.

You're a genius!

[FiloEleven]

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?