Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and learn more about it. Thanks for reading, and for making the site better!

An anonymous reader writes "A Japanese programmer that goes by the handle JA0HXV announced that he has computed Pi to 10 trillion digits. This breaks the previous world record of 5 trillion digits. Computation began in October of 2010 and finished yesterday after multiple hard disk problems, he said. Details in English are not fully available yet, but the Japanese page gives further details. JA0HXV has held computation records for Pi in the past."

Is there any practical application to this sort of thing, either having the number itself, or whatever method this guy used to arrive at it? Or is this a thumb gazing exercise?

If you memorize up to the first zero in pi, you can navigate the circumference of the universe in a perfect circle and when you get to the end of the circle (based on the digits of pi you memorized) you'll be off by less than the width of a human hair.

Re:What Does This Mean? (0)

Anonymous Coward | more than 2 years ago | (#37735888)

I imaging that it has applications in astronomy. When you want to precisely compute something over the distance of light years, you may want more than just 10 digits for Pi.

I can guarantee that this isn't the case. Some of us are excessive and use it to sixteen significant figures or so. Seriously, if we're doing calculations we're using C or Fortran. What type of float do you know that stores so many digits? I just do what I think most people do and fill up the number of bits in the float I'm using - and even that's more than needed.

Re:What Does This Mean? (0)

Anonymous Coward | more than 2 years ago | (#37735988)

And that is why you'll never amount to anything: You're simply not using enough digits.

There are floating format mathematical libraries which support arbitrary precision, but that said I can't see a use for trillions of digits of pi in engineering or science. You can't even write it down given the cost of toner these days. It might be useful as a cryptographic key of course.

You're talking to astronomers - if you saw any codes we've written you'd know full well that most of us can't program for toffee:) What's pretty much standard is to use the float size built into your compiler. Some people redefine them in the headers of their codes and then just ignore it. I dread to think how much numerical noise has been touted as a result over the history of astronomy, only to vanish when looked at a bit more closely at the cost of only a few hundred man-hours and CPU time. Thankfully not much of it will have been published.

Even then, this has no practical consequence whatsoever. If you want to compute the circumference of the galaxy, to accuracy such that your answer is off by less than a nanometer, you still need only ~100 digits of pi.

So yes, in principle you could need more than 10 digits, allthough in practice it's pretty unlikely (it wouldn't matter unless you knew the -radius- with that high precision).

But raising the bar from 5 trillion digits, to 10 trillion ?

Irrelevant in the real world. (possibly there's math-applications, I suppose)

I imaging that it has applications in astronomy. When you want to precisely compute something over the distance of light years, you may want more than just 10 digits for Pi.

As a professional astronomer I can guarantee that distance scale measurements are a little bit less precise than one part over 10^13. Even for most precise measurements, e.g. gravitational waves experiment, 16 digit suffices!

The radius of the part of the universe visible to us is about 46 billion light years [wikimedia.org] or about 4*10^26 meters. The planck length, assumed to be the shortest length there is, is about 1.6*10^-35 meters. That is, the radius of the known universe is 2.7*10^61 planck lengths. Thus with just 62 digits of pi you are as accurate as the laws of physics allow. In practice you'll never need even that. Indeed, you'll not even measure cosmic distances to the meter (27 digits), or even to the kilometer (24 digits). Even measuring to the light year (12 digits) is probably impossible for objects that far out.

I believe that the correct term is "mathsturbation"

Re:What Does This Mean? (0)

Anonymous Coward | more than 2 years ago | (#37736224)

Except I don't know many mathematicians who would find this exciting. They want the hard stuff.

Re:What Does This Mean? (3, Informative)

Anonymous Coward | more than 2 years ago | (#37735900)

No, you only need about 50 decimal places to have an accurate enough approximation to calculate the circumference of the entire universe with less than 1 planck length of error.

This is just a "because we can" exercise. (Also, supposedly, to determine if PI is actually infinite or whether it contains a repeating pattern after you get to a certain point)

Re:What Does This Mean? (0)

Anonymous Coward | more than 2 years ago | (#37735934)

We know pi is irrational, end thus must have an endless decimal presentation without a repeating pattern (see e.g. http://en.wikipedia.org/wiki/Proof_that_%CF%80_is_irrational)

(Also, supposedly, to determine if PI is actually infinite or whether it contains a repeating pattern after you get to a certain point)

What? There's a mathematical proof that pi is irrational (in fact, transcendental). Specifically, if it were not, -1 would be irrational (in fact, transcendental) thanks to the Lindemann-Weierstrass theorem [wikipedia.org] and the fact that e^(pi*i) = -1. The digits cannot simply start repeating after a while (in particular, they cannot eventually just become 0, as happens with, for instance, 1/2 = 0.5000....

Re:What Does This Mean? (0)

Anonymous Coward | more than 2 years ago | (#37736138)

So doing these verifications is all the more reason to make sure our reality doesn't collapse in on itself then.

Any 1st year calculus student should know both that it's been proven that Pi is irrational and does NOT repeat, but should be able to do that proof on their own.

Re:What Does This Mean? (0)

Anonymous Coward | more than 2 years ago | (#37735918)

No, especially since we have the formula to calculate any digit of pi without knowing the previous values...in binary.

The only practical application I've ever heard of for projects like this is as an integrity check on new supercomputers. They compute the first X digits of pi and then compare it to a known result which someone computed and verified earlier.

On a completely separate note, it's "pi", not "Pi". The Greek letter used is lowercase, and the standard English version is similarly lowercase.

Perhaps it is a proper noun which just breaks the typical capitalization rule since it's the transliteration of a lower case letter. That is, capitalizing it would change the meaning of the translation.

Do you mean "phi" instead of "fi", that is, the golden ratio (which is also for some reason not a proper noun)?

Re:What Does This Mean? (0)

Anonymous Coward | more than 2 years ago | (#37736074)

The primary reason for this is to confirm the never-ending nature of pi, if I'm not mistaken. That is, if we were to discover, for example, at the 12 trillionth digit, that pi finally does end, that has wide-spread implications on everything from the microscopic creation of semiconductors to the macroscopic terraforming of a (presumably round) planet. This is kinda like the same reason we sent people into space. Before the Mercury project, we were 100% certain a human being COULD be sent into space, provided a vehicle capable of getting there and sustaining life was available. We could've just said "to hell with it" and skipped directly to Apollo, but the odds that we'd end up missing something critical are pretty damn high, so a shorter, more tame flight was a good way to confirm the more basic theories first.

As for a more practical reason for precision calculation of pi? Hell if I know.

The primary reason for this is to confirm the never-ending nature of pi, if I'm not mistaken.

The never-ending nature of pi is well-confirmed by mathematical proof. It is proved to be irrational (which already implies the never-ending nature) and even transcendental. What might be a motivation is checking the normality, i.e. the assumption that there's no pattern in the digits of pi. Normality has AFAIK not yet been proved.

That is, if we were to discover, for example, at the 12 trillionth digit, that pi finally does end, that has wide-spread implications on everything from the microscopic creation of semiconductors to the macroscopic terraforming of a (presumably round) planet.

No one doing semiconductor physics or terraforming cares even about the tenth digit, let alone the 12 trillionth.

Anonymous Coward | more than 2 years ago | (#37736220)

As for the value itself, unequivocally no (as others have pointed out). Even a thousand digits is overkill.

If I remember correctly, a previous 2.7 trillion digit was intended to showcase a sexy multiplication algorithm for really really big inputs. That's from memory though, and I still can't track down much in the way of details. In particular, I couldn't see if they claim to be asymptotically faster than the other state-of-the-art approach, which uses FFT and is pretty close the the theoretical lower bound on multiplication complexity.

Also, I suppose it's an exercise in supercomputer engineering. Damn impressive, to be sure.

And although I'm not first, let me congratulate Shigeru on a job well done! Oh, and to the idiot complaining of all the wasted CO2, please turn in your geek/nerd card now: computing Pi (and e and...) is NEVER a waste!:P

No we couldn't, that would be double u as w is vv. And due to the Romans not having a u, they would use v instead hence double u looking more like double v.

Quantum computing is about algorithmic efficiency, not speed. So calculating pi will be a whole lot slower until you find and implement an quantum algorithm that is more efficient than classical solutions.

JA0HXV's current problem (0)

Anonymous Coward | more than 2 years ago | (#37735882)

The thought on JA0HXV's mind right now: "How the hell can I MONETIZE this amazing feat?!"

I was working on drawing a perfect circle and 5 trillion digits were just not good enough.

Thank you for wasting the earths resources (electricity, etc..) to make the world a better place!

Re:Finally! (0)

Anonymous Coward | more than 2 years ago | (#37735982)

Finally!

I was working on drawing a perfect circle and 5 trillion digits were just not good enough.

Thank you for wasting the earths resources (electricity, etc..) to make the world a better place!

Interestingly. The earth resources was to make something NOT of this world a better place. Or at least not in our observable by human universe at this point of time.

Stolen from wikipedia:

For example, the decimal representation of truncated to 11 decimal places is good enough to estimate the circumference of any circle that fits inside the Earth with an error of less than one millimetre, and the decimal representation of truncated to 39 decimal places is sufficient to estimate the circumference of any circle that fits in the observable universe with precision comparable to the radius of a hydrogen atom

I was under the impression a modenr Icore 7 could do 70,000 mips. That is 70 billion instructions per second. With that and cheap ram you could get to 10 trillion digits in minutes. You can just page the previous digits to disk as you move along.

"Am I missing something?"
Ummm, they require calculation, not just generation.

Re:Only 10 trillion? In a whole year? (0)

Anonymous Coward | more than 2 years ago | (#37736012)

I was under the impression a modenr Icore 7 could do 70,000 mips. That is 70 billion instructions per second. With that and cheap ram you could get to 10 trillion digits in minutes. You can just page the previous digits to disk as you move along.

He was using a processor with an outdated instruction set. It was missing the "compute next digit of pi" instruction, so he had to cobble together his own.

Pi? (0)

Anonymous Coward | more than 2 years ago | (#37735952)

The last three trillion digits were all 0, since pi turned out to be rational after all, which turned out to be the key in efficiently factoring large numbers and proving that P=NP. So, we can all go home now, math is done.

This reminds me of a scifi (short) story I read too many years ago - I forget the title or author - I think pi was also being calculated to the Nth and some some magic number was reached and the universe started to unravel. The stars started blinking off, etc.

Wonderful stuff. I read so many short stories in my youth, I can't remember many, what I do remember though is the slightly-musty smell of the books in a library and immediately having to go to the toilette for a nice bowel movement... olfactory triggers are a sometimes weird and inconvenient thing (to this day).

Anyway, this anecdote has as much use to you as the 10 trillionth digit of pi.

Isn't that one of the plot ideas in the book (which the movie was based on) "Contact"?

Scientist travels across interstellar space to meet super-advanced aliens and asks:

"Do you believe in God?"

To which they reply "Yes".

(A little surprised) "Why?"

"We have proof"

(Very surprised) "Proof?! What is it!"

"If you calculate Pi to the n-th digit you will find a message..."

Since I didn't read the book, I'm not sure this is how the exchange went, nor do I know what the "message" was. But it makes a good story! (I think in the Douglas Adams rewrite it was "42").

Anyway how would you determine, when looking at an infinitely long string of "random" numbers, what is a "message"? Couldn't you find, when looking long enough, ANYTHING; like the complete works of Shakespeare (written in the original Klingon?). I think (but again am not entirely sure) that that was the idea behind one of Stanislaw Lem's stories, that the U.S. government detects a signal from deep space and then finds more and more "messages" (meanings?) by subjecting it to more and more sophisticated(?) cryptographic analysis. (Will arbitrarily "strong" cryptanalysis of random noise produce anything you want?)

I guess this sort of thing is the ultimate case of "finding what you're looking for".

P.S. To the mathematicians: are there different kinds of Random numbers? Like aren't some systems are "chaotic" but not truly random? So while, for example, a Mandelbrot pattern may never repeat, does that mean it will show every possible pattern? So maybe Pi is a non-repeating numbers that is not Random. Or is it another kind of Random?

Wen calculating pie in a given number base (I forget which base), there was an abnormally long string of zeros and ones. The length of this string was the product of two prime numbers.

Arrange the zeros and ones into a two-dimensional matrix with one prime's units on the X axis, and the other prime's units on the Y axis.

Yeah, if I remember right, at some point deep inside pi, there is a message primer. It establishes that there is a message to get your attention. Then you begin to decode it, like you said. The trippy part of that is that the message is embedded into the very fabric of the universe through math.

Anyway how would you determine, when looking at an infinitely long string of "random" numbers, what is a "message"?

And I suppose people are thinking it's going to be something in a current language... But I'm thinking some DNA-like thing instead.

Re:What's the message? (0)

Anonymous Coward | more than 2 years ago | (#37736112)

P.S. To the mathematicians: are there different kinds of Random numbers? Like aren't some systems are "chaotic" but not truly random? So while, for example, a Mandelbrot pattern may never repeat, does that mean it will show every possible pattern? So maybe Pi is a non-repeating numbers that is not Random. Or is it another kind of Random?

An open question is if pi is a normal number [wikipedia.org] . This describes a (strong) form of randomness in the digits of a number.

We're not sure pi is normal. So it is believed that the complete works of Shakespeare in Klingon are hidden in pi, but you'll probably need a whole library to describe its location.

By using statistics. If a message is significantly longer than you'd expect, compared to how far you've calculated pi, then it's statistically odd.

Calulating pi to 1000 digits and somewhere finding 12 would be expected. finding 1234 would be odd, finding 12345 would be highly unlikely. Finding 12345678901234567890 in the first 1000 digits of pi, would be *extremely* odd.

At some point, believing that something that a message is a message, rather than random noise, becomes more rational than the alternative. Though I suppose you could always debate at *which* point that happens.

22/7 (0)

Anonymous Coward | more than 2 years ago | (#37735994)

An approximation sufficient for all earthly tasks.

Of course the BSJ rationalisation to 3 is probably a step too far, but 3.142 enough for wheelwrights and general metalbenders,.

Anonymous Coward | more than 2 years ago | (#37736102)

A one time pad that can generated perfectly by anyone using simple maths and published techniques? Try worst pad set ever, by telling your adversary the pad is found in the first 10 trillion digits of pi, you just reduced the search space to at worst log2(10*10^12) 45 bits.

Probably not nearly as much as other useless endeavors, such as playing computer games, updating facebook status, or watching super bowl. And reading slashdot, of course.

The sagemath.org open source computation engine has a 2 line benchmark that computes Pi to 5 million digits.

It took my Atom desktop computer about 15 minutes. I watched it with Top. It sucked up 99 to 100% of the CPU and strangely only 200 Mb out of 2 Gig of RAM. Also, it didn't use the Linux swap at all. It kind of got me puzzling that my Ubuntu Linux might be missing some performance optimizations.

What to do with it? Resume studying mathematics. Make a pretty good symmetric encryption gadget with a CD of huge encryption keys.

## What Does This Mean? (4, Insightful)

## Frosty Piss (770223) | more than 2 years ago | (#37735836)

Is there any practical application to this sort of thing, either having the number itself, or whatever method this guy used to arrive at it? Or is this a thumb gazing exercise?

## Re:What Does This Mean? (1)

## Hotweed Music (2017854) | more than 2 years ago | (#37735842)

## Re:What Does This Mean? (2)

## hcs_$reboot (1536101) | more than 2 years ago | (#37735930)

You'll never need more than 10 significant figures

Do you work at the CERN?

## Re:What Does This Mean? (0)

## Anonymous Coward | more than 2 years ago | (#37735858)

No.

## Re:What Does This Mean? (0)

## Anonymous Coward | more than 2 years ago | (#37735936)

No.

Entropy!

## Re:What Does This Mean? (2, Funny)

## Anonymous Coward | more than 2 years ago | (#37735860)

a message from god shows up in binary once you get to 20 trillion digits.

## Re:What Does This Mean? (0)

## Anonymous Coward | more than 2 years ago | (#37735914)

a message from god shows up in binary once you get to 20 trillion digits.

20 trillion digits and the answer to life is only 42

## Re:What Does This Mean? (1)

## maxwell demon (590494) | more than 2 years ago | (#37736136)

But maybe the question is: "What is the 20 trillionth digit of pi in base 97?"

## Re:What Does This Mean? (1)

## Kenoli (934612) | more than 2 years ago | (#37735878)

## Re:What Does This Mean? (4, Interesting)

## nacturation (646836) | more than 2 years ago | (#37736208)

If you memorize up to the first zero in pi, you can navigate the circumference of the universe in a perfect circle and when you get to the end of the circle (based on the digits of pi you memorized) you'll be off by less than the width of a human hair.

## Re:What Does This Mean? (0)

## Anonymous Coward | more than 2 years ago | (#37735888)

I imaging that it has applications in astronomy. When you want to precisely compute something over the distance of light years, you may want more than just 10 digits for Pi.

## Re:What Does This Mean? (1)

## boristhespider (1678416) | more than 2 years ago | (#37735910)

I can guarantee that this isn't the case. Some of us are excessive and use it to sixteen significant figures or so. Seriously, if we're doing calculations we're using C or Fortran. What type of float do you know that stores so many digits? I just do what I think most people do and fill up the number of bits in the float I'm using - and even that's more than needed.

## Re:What Does This Mean? (0)

## Anonymous Coward | more than 2 years ago | (#37735988)

And that is why you'll never amount to anything: You're simply not using enough digits.

## Re:What Does This Mean? (1)

## MichaelSmith (789609) | more than 2 years ago | (#37736108)

There are floating format mathematical libraries which support arbitrary precision, but that said I can't see a use for trillions of digits of pi in engineering or science. You can't even write it down given the cost of toner these days. It might be useful as a cryptographic key of course.

## Re:What Does This Mean? (1)

## boristhespider (1678416) | more than 2 years ago | (#37736194)

You're talking to astronomers - if you saw any codes we've written you'd know full well that most of us can't program for toffee :) What's pretty much standard is to use the float size built into your compiler. Some people redefine them in the headers of their codes and then just ignore it. I dread to think how much numerical noise has been touted as a result over the history of astronomy, only to vanish when looked at a bit more closely at the cost of only a few hundred man-hours and CPU time. Thankfully not much of it will have been published.

## Re:What Does This Mean? (2)

## neyla (2455118) | more than 2 years ago | (#37736054)

Even then, this has no practical consequence whatsoever. If you want to compute the circumference of the galaxy, to accuracy such that your answer is off by less than a nanometer, you still need only ~100 digits of pi.

So yes, in principle you could need more than 10 digits, allthough in practice it's pretty unlikely (it wouldn't matter unless you knew the -radius- with that high precision).

But raising the bar from 5 trillion digits, to 10 trillion ?

Irrelevant in the real world. (possibly there's math-applications, I suppose)

## Re:What Does This Mean? (3, Informative)

## oloferne (167995) | more than 2 years ago | (#37736066)

I imaging that it has applications in astronomy. When you want to precisely compute something over the distance of light years, you may want more than just 10 digits for Pi.

As a professional astronomer I can guarantee that distance scale measurements are a little bit less precise than one part over 10^13. Even for most precise measurements, e.g. gravitational waves experiment, 16 digit suffices!

## Re:What Does This Mean? (5, Informative)

## maxwell demon (590494) | more than 2 years ago | (#37736178)

The radius of the part of the universe visible to us is about 46 billion light years [wikimedia.org] or about 4*10^26 meters. The planck length, assumed to be the shortest length there is, is about 1.6*10^-35 meters. That is, the radius of the known universe is 2.7*10^61 planck lengths. Thus with just 62 digits of pi you are as accurate as the laws of physics allow. In practice you'll never need even that. Indeed, you'll not even measure cosmic distances to the meter (27 digits), or even to the kilometer (24 digits). Even measuring to the light year (12 digits) is probably impossible for objects that far out.

## Re:What Does This Mean? (5, Funny)

## Rizimar (1986164) | more than 2 years ago | (#37735890)

## Re:What Does This Mean? (0)

## Anonymous Coward | more than 2 years ago | (#37736224)

Except I don't know many mathematicians who would find this exciting. They want the hard stuff.

## Re:What Does This Mean? (3, Informative)

## Anonymous Coward | more than 2 years ago | (#37735900)

No, you only need about 50 decimal places to have an accurate enough approximation to calculate the circumference of

the entire universewith less than 1 planck length of error.This is just a "because we can" exercise. (Also, supposedly, to determine if PI is actually infinite or whether it contains a repeating pattern after you get to a certain point)

## Re:What Does This Mean? (0)

## Anonymous Coward | more than 2 years ago | (#37735934)

We know pi is irrational, end thus must have an endless decimal presentation without a repeating pattern (see e.g. http://en.wikipedia.org/wiki/Proof_that_%CF%80_is_irrational)

## Re:What Does This Mean? (5, Informative)

## FrootLoops (1817694) | more than 2 years ago | (#37736034)

(Also, supposedly, to determine if PI is actually infinite or whether it contains a repeating pattern after you get to a certain point)

What? There's a mathematical proof that pi is irrational (in fact, transcendental). Specifically, if it were not, -1 would be irrational (in fact, transcendental) thanks to the Lindemann-Weierstrass theorem [wikipedia.org] and the fact that e^(pi*i) = -1. The digits cannot simply start repeating after a while (in particular, they cannot eventually just become 0, as happens with, for instance, 1/2 = 0.5000... .

## Re:What Does This Mean? (0)

## Anonymous Coward | more than 2 years ago | (#37736138)

So doing these verifications is all the more reason to make sure our reality doesn't collapse in on itself then.

## Re:What Does This Mean? (1)

## TheWanderingHermit (513872) | more than 2 years ago | (#37736218)

Any 1st year calculus student should know both that it's been proven that Pi is irrational and does NOT repeat, but should be able to do that proof on their own.

## Re:What Does This Mean? (0)

## Anonymous Coward | more than 2 years ago | (#37735918)

No, especially since we have the formula to calculate any digit of pi without knowing the previous values...in binary.

## Re:What Does This Mean? (3, Funny)

## Kilrah_il (1692978) | more than 2 years ago | (#37736192)

I can calculate any digit of pi in binary off the top of my head with 50% accuracy.

## Re:What Does This Mean? (4, Informative)

## FrootLoops (1817694) | more than 2 years ago | (#37735980)

The only practical application I've ever heard of for projects like this is as an integrity check on new supercomputers. They compute the first X digits of pi and then compare it to a known result which someone computed and verified earlier.

On a completely separate note, it's "pi", not "Pi". The Greek letter used is lowercase, and the standard English version is similarly lowercase.

## Re:What Does This Mean? (1)

## hedwards (940851) | more than 2 years ago | (#37736008)

Which if you think about it is really strange for pi to not be a proper noun.

## Re:What Does This Mean? (0)

## Black Parrot (19622) | more than 2 years ago | (#37736076)

Which if you think about it is really strange for pi to not be a proper noun.

Stranger still that "proper noun" isn't a proper noun.

## Re:What Does This Mean? (2)

## fph il quozientatore (971015) | more than 2 years ago | (#37736132)

## Re:What Does This Mean? (1)

## FrootLoops (1817694) | more than 2 years ago | (#37736122)

## Re:What Does This Mean? (1)

## LordLucless (582312) | more than 2 years ago | (#37736140)

No more stranger than one, two three, four, five, fi or e.

## Re:What Does This Mean? (1)

## FrootLoops (1817694) | more than 2 years ago | (#37736234)

## Re:What Does This Mean? (0)

## Anonymous Coward | more than 2 years ago | (#37736074)

The primary reason for this is to confirm the never-ending nature of pi, if I'm not mistaken. That is, if we were to discover, for example, at the 12 trillionth digit, that pi finally does end, that has wide-spread implications on everything from the microscopic creation of semiconductors to the macroscopic terraforming of a (presumably round) planet. This is kinda like the same reason we sent people into space. Before the Mercury project, we were 100% certain a human being COULD be sent into space, provided a vehicle capable of getting there and sustaining life was available. We could've just said "to hell with it" and skipped directly to Apollo, but the odds that we'd end up missing something critical are pretty damn high, so a shorter, more tame flight was a good way to confirm the more basic theories first.

As for a more practical reason for precision calculation of pi? Hell if I know.

## Re:What Does This Mean? (1)

## hcs_$reboot (1536101) | more than 2 years ago | (#37736166)

The primary reason for this is to confirm the never-ending nature of pi,

Or find a cycle in the digits, a pattern that repeats itself (like 27/11 = 2.454545...).

## Re:What Does This Mean? (2)

## maxwell demon (590494) | more than 2 years ago | (#37736236)

The never-ending nature of pi is well-confirmed by mathematical proof. It is proved to be irrational (which already implies the never-ending nature) and even transcendental. What might be a motivation is checking the normality, i.e. the assumption that there's no pattern in the digits of pi. Normality has AFAIK not yet been proved.

No one doing semiconductor physics or terraforming cares even about the tenth digit, let alone the 12 trillionth.

## Re:What Does This Mean? (1)

## nicvsor (562753) | more than 2 years ago | (#37736094)

## Re:What Does This Mean? (1)

## idji (984038) | more than 2 years ago | (#37736150)

## Re:What Does This Mean? (1)

## vikingpower (768921) | more than 2 years ago | (#37736204)

## Re:What Does This Mean? (1)

## FreakyGreenLeaky (1536953) | more than 2 years ago | (#37736210)

What Does This Mean?42

## Re:What Does This Mean? (1)

## Anonymous Coward | more than 2 years ago | (#37736220)

As for the value itself, unequivocally no (as others have pointed out). Even a thousand digits is overkill.

If I remember correctly, a previous 2.7 trillion digit was intended to showcase a sexy multiplication algorithm for really really big inputs. That's from memory though, and I still can't track down much in the way of details. In particular, I couldn't see if they claim to be asymptotically faster than the other state-of-the-art approach, which uses FFT and is pretty close the the theoretical lower bound on multiplication complexity.

Also, I suppose it's an exercise in supercomputer engineering. Damn impressive, to be sure.

## Madness (1)

## aglider (2435074) | more than 2 years ago | (#37735850)

All that CO2 for nothing!

## Re:Madness (1)

## wanzeo (1800058) | more than 2 years ago | (#37735944)

What a pi in the sky project.

## Re:Madness (-1)

## Anonymous Coward | more than 2 years ago | (#37736004)

## How to actually verify? (0)

## Anonymous Coward | more than 2 years ago | (#37735852)

10 trillion digits is great and all, but how do they verify that it isn't random numbers after the 18475930th digit?

## Re:How to actually verify? (1)

## hcs_$reboot (1536101) | more than 2 years ago | (#37735924)

how do they verify that it isn't random numbers

They actually verify the formula, method and hardware used, and if it is actually feasible within a reasonable time.

## Re:How to actually verify? (0)

## Anonymous Coward | more than 2 years ago | (#37736022)

By computing it twice with two different methods.

## Why not (1)

## JustOK (667959) | more than 2 years ago | (#37735854)

would just using =Right(Pi, 1) be quicker?

## Re:Why not (1)

## hcs_$reboot (1536101) | more than 2 years ago | (#37735898)

would just using =Right(Pi, 1) be quicker?

There is an overflow risk. Try Right(Pi,1,10000000000000) instead.

## Re:Why not (1)

## FrootLoops (1817694) | more than 2 years ago | (#37736244)

## too much time (-1)

## Anonymous Coward | more than 2 years ago | (#37735864)

this guy has too much time on his hands... life is short enough as it is without wasting it with useless shit like this.

## Re:too much time (0)

## Anonymous Coward | more than 2 years ago | (#37736130)

It is best to spend the little time that you have doing something you love.

## Re:too much time (1)

## Hognoxious (631665) | more than 2 years ago | (#37736186)

... and when it gets sore from doing that, then you fill in the time by calculating the digits of pi ...

## Re:too much time (2)

## localman (111171) | more than 2 years ago | (#37736188)

Yes, like reading about it on slashdot and complaining that he's wasting time :)

## Ham Radio Callsign (3, Insightful)

## storkus (179708) | more than 2 years ago | (#37735866)

Kind of obvious to me, being one. Here is his info:

http://hamcall.net/call/JA0HXV [hamcall.net]

And although I'm not first, let me congratulate Shigeru on a job well done! Oh, and to the idiot complaining of all the wasted CO2, please turn in your geek/nerd card now: computing Pi (and e and...) is NEVER a waste! :P

## Re:Ham Radio Callsign (1)

## thephydes (727739) | more than 2 years ago | (#37736200)

## pi, not Pi (0)

## Anonymous Coward | more than 2 years ago | (#37735874)

since the symbol is the

lower caseGreek letter pi.## Re:pi, not Pi (0)

## Anonymous Coward | more than 2 years ago | (#37735928)

spelling outaletter? I suppose we could just start writing "w" as "double-you"; it makes just as much sense.## Re:pi, not Pi (1)

## hedwards (940851) | more than 2 years ago | (#37736024)

No we couldn't, that would be double u as w is vv. And due to the Romans not having a u, they would use v instead hence double u looking more like double v.

## Re:pi, not Pi (1)

## Patch86 (1465427) | more than 2 years ago | (#37736106)

You would be assuming that Slashcode can handle displaying a Greek letter. I'm not going to try, but that's probably a ropey assumption to make...

## Quantum Computing? (2)

## luke923 (778953) | more than 2 years ago | (#37735876)

Supposedly, this ran for nearly a year -- imagine how fast someone can come to the same result if he/she was dealing in qubits.

## Re:Quantum Computing? (1)

## MacTO (1161105) | more than 2 years ago | (#37736040)

Quantum computing is about algorithmic efficiency, not speed. So calculating pi will be a whole lot slower until you find and implement an quantum algorithm that is more efficient than classical solutions.

## JA0HXV's current problem (0)

## Anonymous Coward | more than 2 years ago | (#37735882)

The thought on JA0HXV's mind right now: "How the hell can I MONETIZE this amazing feat?!"

## Contact (2)

## GrahamCox (741991) | more than 2 years ago | (#37735894)

## Re:Contact (2)

## Black Parrot (19622) | more than 2 years ago | (#37736096)

The big question is, does it turn out to contain the plans for a teleporting device?

Undoubtedly it does, embedded somewhere in the sequence.

Also the text of every novel that will ever be written.

Just got to figure out what the encoding is. And figure out where the relevant substring starts.

## Re:Contact (0)

## Anonymous Coward | more than 2 years ago | (#37736190)

It's there in every encoding.

## Re:Contact (0)

## Anonymous Coward | more than 2 years ago | (#37736124)

I hope not. I need one of those like I need a hole in my head!

## Someone pick a number between 0 and 9! (1)

## sgraar (958944) | more than 2 years ago | (#37735904)

I just computed pi to 10 trillion and 1 digits!

## Finally! (1)

## Wattos (2268108) | more than 2 years ago | (#37735908)

Finally!

I was working on drawing a perfect circle and 5 trillion digits were just not good enough.

Thank you for wasting the earths resources (electricity, etc..) to make the world a better place!

## Re:Finally! (0)

## Anonymous Coward | more than 2 years ago | (#37735982)

Finally!

I was working on drawing a perfect circle and 5 trillion digits were just not good enough.

Thank you for wasting the earths resources (electricity, etc..) to make the world a better place!

Interestingly. The earth resources was to make something NOT of this world a better place. Or at least not in our observable by human universe at this point of time.

Stolen from wikipedia:

For example, the decimal representation of truncated to 11 decimal places is good enough to estimate the circumference of any circle that fits inside the Earth with an error of less than one millimetre, and the decimal representation of truncated to 39 decimal places is sufficient to estimate the circumference of any circle that fits in the observable universe with precision comparable to the radius of a hydrogen atom

## Re:Finally! (1)

## FrootLoops (1817694) | more than 2 years ago | (#37736052)

Thank you for wasting the earths resources (electricity, etc..) to make the world a better place!

Aren't you wasting those resources by reading such a story in the first place?

## Only 10 trillion? In a whole year? (1)

## Billly Gates (198444) | more than 2 years ago | (#37735920)

I was under the impression a modenr Icore 7 could do 70,000 mips. That is 70 billion instructions per second. With that and cheap ram you could get to 10 trillion digits in minutes. You can just page the previous digits to disk as you move along.

Am I missing something?

## Re:Only 10 trillion? In a whole year? (1)

## chrism238 (657741) | more than 2 years ago | (#37735948)

## Re:Only 10 trillion? In a whole year? (0)

## Anonymous Coward | more than 2 years ago | (#37736012)

I was under the impression a modenr Icore 7 could do 70,000 mips. That is 70 billion instructions per second. With that and cheap ram you could get to 10 trillion digits in minutes. You can just page the previous digits to disk as you move along.

Am I missing something?

yes

## Re:Only 10 trillion? In a whole year? (1)

## FrootLoops (1817694) | more than 2 years ago | (#37736062)

## Pi? (0)

## Anonymous Coward | more than 2 years ago | (#37735952)

That's like 3.14.

There, done and done.

## Even better (2)

## timeOday (582209) | more than 2 years ago | (#37735962)

## Re:Even better (2)

## FreakyGreenLeaky (1536953) | more than 2 years ago | (#37736238)

This reminds me of a scifi (short) story I read too many years ago - I forget the title or author - I think pi was also being calculated to the Nth and some some magic number was reached and the universe started to unravel. The stars started blinking off, etc.

Wonderful stuff. I read so many short stories in my youth, I can't remember many, what I do remember though is the slightly-musty smell of the books in a library and immediately having to go to the toilette for a nice bowel movement... olfactory triggers are a sometimes weird and inconvenient thing (to this day).

Anyway, this anecdote has as much use to you as the 10 trillionth digit of pi.

## What's the message? (1)

## wisebabo (638845) | more than 2 years ago | (#37735984)

Isn't that one of the plot ideas in the book (which the movie was based on) "Contact"?

Scientist travels across interstellar space to meet super-advanced aliens and asks:

"Do you believe in God?"

To which they reply "Yes".

(A little surprised) "Why?"

"We have proof"

(Very surprised) "Proof?! What is it!"

"If you calculate Pi to the n-th digit you will find a message..."

Since I didn't read the book, I'm not sure this is how the exchange went, nor do I know what the "message" was. But it makes a good story! (I think in the Douglas Adams rewrite it was "42").

Anyway how would you determine, when looking at an infinitely long string of "random" numbers, what is a "message"? Couldn't you find, when looking long enough, ANYTHING; like the complete works of Shakespeare (written in the original Klingon?). I think (but again am not entirely sure) that that was the idea behind one of Stanislaw Lem's stories, that the U.S. government detects a signal from deep space and then finds more and more "messages" (meanings?) by subjecting it to more and more sophisticated(?) cryptographic analysis. (Will arbitrarily "strong" cryptanalysis of random noise produce anything you want?)

I guess this sort of thing is the ultimate case of "finding what you're looking for".

P.S. To the mathematicians: are there different kinds of Random numbers? Like aren't some systems are "chaotic" but not truly random? So while, for example, a Mandelbrot pattern may never repeat, does that mean it will show every possible pattern? So maybe Pi is a non-repeating numbers that is not Random. Or is it another kind of Random?

## Re:What's the message? (2)

## SpryGuy (206254) | more than 2 years ago | (#37736006)

Wen calculating pie in a given number base (I forget which base), there was an abnormally long string of zeros and ones. The length of this string was the product of two prime numbers.

Arrange the zeros and ones into a two-dimensional matrix with one prime's units on the X axis, and the other prime's units on the Y axis.

The result was a "picture" of a circle.

## Re:What's the message? (2)

## d474 (695126) | more than 2 years ago | (#37736084)

## Re:What's the message? (1)

## Frosty Piss (770223) | more than 2 years ago | (#37736016)

Anyway how would you determine, when looking at an infinitely long string of "random" numbers, what is a "message"?

And I suppose people are thinking it's going to be something in a current language... But I'm thinking some DNA-like thing instead.

## Re:What's the message? (0)

## Anonymous Coward | more than 2 years ago | (#37736112)

P.S. To the mathematicians: are there different kinds of Random numbers? Like aren't some systems are "chaotic" but not truly random? So while, for example, a Mandelbrot pattern may never repeat, does that mean it will show every possible pattern? So maybe Pi is a non-repeating numbers that is not Random. Or is it another kind of Random?

An open question is if pi is a normal number [wikipedia.org] . This describes a (strong) form of randomness in the digits of a number.

## Re:What's the message? (1)

## BlackPignouf (1017012) | more than 2 years ago | (#37736152)

Good question.

I suppose you'll find this article interesting :

http://en.wikipedia.org/wiki/Normal_number [wikipedia.org]

We're not sure pi is normal.

So it is believed that the complete works of Shakespeare in Klingon are hidden in pi, but you'll probably need a whole library to describe its location.

## Re:What's the message? (1)

## neyla (2455118) | more than 2 years ago | (#37736164)

By using statistics. If a message is significantly longer than you'd expect, compared to how far you've calculated pi, then it's statistically odd.

Calulating pi to 1000 digits and somewhere finding 12 would be expected. finding 1234 would be odd, finding 12345 would be highly unlikely. Finding 12345678901234567890 in the first 1000 digits of pi, would be *extremely* odd.

At some point, believing that something that a message is a message, rather than random noise, becomes more rational than the alternative. Though I suppose you could always debate at *which* point that happens.

## 22/7 (0)

## Anonymous Coward | more than 2 years ago | (#37735994)

An approximation sufficient for all earthly tasks.

Of course the BSJ rationalisation to 3 is probably a step too far, but 3.142 enough for wheelwrights and general metalbenders,.

## Now that is a key! (1)

## FlyingGuy (989135) | more than 2 years ago | (#37736030)

Talk about the best one time pad set ever.

## Re:Now that is a key! (2, Informative)

## Anonymous Coward | more than 2 years ago | (#37736102)

A one time pad that can generated perfectly by anyone using simple maths and published techniques? Try worst pad set ever, by telling your adversary the pad is found in the first 10 trillion digits of pi, you just reduced the search space to at worst log2(10*10^12) 45 bits.

## Electricity usage (0)

## psychonaut (65759) | more than 2 years ago | (#37736048)

## Re:Electricity usage (5, Insightful)

## Arlet (29997) | more than 2 years ago | (#37736072)

Probably not nearly as much as other useless endeavors, such as playing computer games, updating facebook status, or watching super bowl. And reading slashdot, of course.

## Re:Electricity usage (1)

## Black Parrot (19622) | more than 2 years ago | (#37736134)

I am curious to know how much electricity was wasted on this apparently useless endeavour.

I think you're just suffering pi nos envy. He's obviously got way more pi nos than you do.

## Re:Electricity usage (0)

## Anonymous Coward | more than 2 years ago | (#37736174)

Not as much as will be consumed working it out to 20 trillion dp

## Dang! (0)

## Anonymous Coward | more than 2 years ago | (#37736064)

Pi Computed To 10 Trillion DigitsDang! Now I have to change my password again. Sigh ...

## Proof? (0)

## Anonymous Coward | more than 2 years ago | (#37736116)

How would someone go about confirming that the number is real and not just a random number generator spewing digits into a file?

## Re:Proof? (1)

## Zerth (26112) | more than 2 years ago | (#37736216)

You can calculate any particular digit of pi(in base 16) without calculating all the preceding digits to verify they are correct.

Pi = SUM(k=0 to infinity) 16^(-k) [ 4/(8k+1) - 2/(8k+4) - 1/(8k+5) - 1/(8k+6) ].

Hopefully that won't get mangled.

## Sagemath.org can do many digits (2)

## beachdog (690633) | more than 2 years ago | (#37736156)

The sagemath.org open source computation engine has a 2 line benchmark that computes Pi to 5 million digits.

It took my Atom desktop computer about 15 minutes. I watched it with Top. It sucked up 99 to 100% of the CPU and strangely only 200 Mb out of 2 Gig of RAM.

Also, it didn't use the Linux swap at all. It kind of got me puzzling that my Ubuntu Linux might be missing some performance optimizations.

What to do with it? Resume studying mathematics. Make a pretty good symmetric encryption gadget with a CD of huge encryption keys.

easy:

sage: numerical_approx(pi,digits=50)

3.141592653589793238462643383279502884197169399

takes a long time:

sage: time a = N(pi, digits=5000000)

## Computers get faster and faster (1)

## Lord Lode (1290856) | more than 2 years ago | (#37736170)

So the record will be broken over and over and over again...

## Last digit (1)

## lazykoala (2477144) | more than 2 years ago | (#37736230)

## English (correct) (0)

## Anonymous Coward | more than 2 years ago | (#37736250)

http://translate.google.com/translate?sl=ja&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fja0hxv.calico.jp%2Fpai%2Fpietc.html