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Math Science Hardware

5 Trillion Digits of Pi — a New World Record 299

KPexEA writes "Alexander J. Yee & Shigeru Kondo claim to have calculated the number pi to 5 trillion places, on a single desktop and in record time. The main computation took 90 days on Shigeru Kondo's desktop. Verification was done using two separate computers. The program that was used for the main computation is y-cruncher v0.5.4.9138 Alpha." Looks like the chart of computer-era approximations of Pi here might need an update.
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5 Trillion Digits of Pi — a New World Record

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  • by Lord Lode ( 1290856 ) on Friday August 06, 2010 @05:47AM (#33159188)

    Hmm, I can think of an interesting and useful use of it: doing various statistics and randomness tests on those digits, finding patterns in their order, and so on.

    But I don't suppose that's what those contests to find the most PI digits are about.

  • by Anonymous Coward on Friday August 06, 2010 @05:48AM (#33159196)

    But don't we have algorithms which let us calculate pi to an arbitrary number of digits? Well-known series methods computed using algorithms which have been tuned and re-tuned to the point where it's not really possible to make further major computational optimizations? Therefore this isn't so much a new accomplishment as it is "hey look, I left my pi calculating program running longer than the last guy" modified by the occasional minor optimization tweak and running on faster hardware?

    Okay, great, you now have a new more precise fixed value for pi. This means you can calculate things involving pi to precision even most physicists can't find a use for. I'm sure that's nice. Someone somewhere maybe has a use for it. Maybe this made that person's day. But is it really, really something that's newsworthy? And if hypothetical "needing pi to 5 trillion digits" guy needed it to that precision that badly - wouldn't he have already let the calculation run long enough to get it already if this particular calculation only took 90 days?

  • Re:Obviously a fraud (Score:5, Interesting)

    by fotoguzzi ( 230256 ) on Friday August 06, 2010 @06:47AM (#33159408)

    They just took the number 3.14159 and added a load of random digits to the end - let's face it, nobody's going to check!

    Reminds me of the MAX light rail station in the zoo tunnel in Portland, Oregon. Apparently there is the first 100 (1000?) digits of pi chiseled into one of the walls. A writer noticed that the first digits were correct, but quickly went astray. But later in the sequence, there was a recognizable early string of digits. The writer sleuthed that the sculptor had used the Book of Pi, which has the numbers in blocks of ten digits in five (or so) columns. In the book, you read the first row and then the next row.* The sculptor had read the first column, then the next column...

    * or the other way around

  • by ShadowFalls ( 991965 ) on Friday August 06, 2010 @07:01AM (#33159458)
    Surprised that some group out there hasn't taken upon itself to broadcast a consistent calculation of Pi out into space. That way we will finally get an alien invasion scenario just to get us to stop.
  • by Anonymous Coward on Friday August 06, 2010 @07:04AM (#33159482)

    "finding patterns" would be genuinely interesting, since we are pretty confident that Pi is a _normal number_

    (Normal numbers have all the possible digits occurring evenly in every base. If Pi is normal, then if you pick a decimal digit of Pi randomly, the chance of it being a 7 is exactly 1-in-10)

    We know that almost all real numbers are normal, but we don't have a proof that any interesting ones (including Pi) are, although if you get the first few hundred digits printed out and stare at them you'll agree it _looks_ pretty random.

  • Re:KGB it! (Score:4, Interesting)

    by b0r0din ( 304712 ) on Friday August 06, 2010 @08:17AM (#33159856)

    in binary, it's either a 1 or a 0, so you have a 50/50 chance of being right.

    In unary it's just 0. It's zeroes all the way down. Easy to calculate too, you just turn off your computer forever. Dead computing is the new trend.

  • by Anonymous Coward on Friday August 06, 2010 @09:01AM (#33160312)

    That was just the 'message' left in Pi. I believe in the book, Pi was just the easy one to find (calculated to a few hundred trillion places or something) - the 'better' messages were in the harder/longer to calculate irrational numbers which were still beyond our ability to find at the end of the book.

  • by MichaelSmith ( 789609 ) on Friday August 06, 2010 @09:04AM (#33160348) Homepage Journal

    But maybe that just demonstrates the limits of our thinking. We re used to the parameters of our universe and have trouble imagining how things could be different.

  • by tibit ( 1762298 ) on Friday August 06, 2010 @11:14AM (#33162436)

    I'm serious. How would you even start an argument about PI not being a physical constant? It's really just a matter of definition, and in that sense there's no argument.

    But we say that physical constants are some things we measure, and other seemingly fundamental things we can measure are not (like PI). PI can be of course measured to a good few digits by manufacturing a sphere or a disk/cylinder, and then measuring the circumference and radius. We then also have mathematical theories that can come up with PI to arbitrary accuracy, but that's just a bonus. We don't know -- maybe we will come up with similarly good theories for other things that can be measured, say the fine-structure constant.

    We really don't know how closely the physics of our Universe are coupled with the structure we see in the mathematics. It's kind of philosophical, but we "discover" things in mathematics. So what is this thing that we discover then -- where is it. In our minds only? Or is it really just our minds picking it up, noticing it.

    So I can't really say anyone can quite wrap his/her mind around it. I'd go further: anyone claiming to be able to do so is quite a kook. It's like claiming to understand why quantum mechanics or gravitation behaves just like so. We have no clue *why* it behaves just like so, exactly like we have no clue what to make of the value of PI.

    We know how to apply all this knowledge, but we know of no "ulterior motive" for it. Certain phenomena can be inferred from other, more fundamental ones -- say Bernoulli effect is just a manifestation of laws of conservation intertwined with laws of dynamics -- so we can say why we see the Bernoulli effect. But we can't say why the quantum mechanical behavior of the atoms that make up the medium is just so -- we know no more basic stuff to explain that. We just observe it to be so, but can claim no further insight.

    Same with PI: we have no clue where it came from. I don't claim we need to have such a clue -- but please, don't claim more insight than we actually possess. We are pretty clueless and IMHO that's what's exciting: there's still plenty of stuff to discover.

  • Re:KGB it! (Score:3, Interesting)

    by justleavealonemmmkay ( 1207142 ) on Friday August 06, 2010 @02:02PM (#33165270)

    no, in base Pi, Pi=1*Pi^1 + 0*Pi^0 + 0*Pi^-1 + 0*Pi^-2 + 0*Pi^-3 + 0*Pi^-4...

    hence, in base Pi, Pi= 10.0000000000..., like in base 10, 10=10.00000000000..., like in base 2, 2=10.0000000...

"Oh my! An `inflammatory attitude' in alt.flame? Never heard of such a thing..." -- Allen Gwinn, allen@sulaco.Sigma.COM