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Math Supercomputing

Pi Calculated To Record 2.5 Trillion Digits 432

Posted by samzenpus
from the almost-there dept.
Joshua writes "Researchers from Japan have calculated Pi to over 2.5 trillion decimals using the T2K Open Supercomputer (which is currently ranked 47th in the world according to a June, 2009 report from Top500.org). This new number more than doubles the previous record of about 1.2 trillion decimals set in 2002 by another Japanese research team. Unfortunately, there still seems to be no pattern."
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Pi Calculated To Record 2.5 Trillion Digits

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  • Well... (Score:0, Insightful)

    by Anonymous Coward on Wednesday August 19, 2009 @10:38PM (#29128373)

    Just because nobody has detected a pattern doesn't mean there isn't one.

  • by Anonymous Coward on Wednesday August 19, 2009 @10:42PM (#29128405)

    Otherwise how would you calculate it? The "pattern" is it matches the stream of digits produced by a simple algorithm!

  • by Tmack (593755) on Wednesday August 19, 2009 @10:48PM (#29128459) Homepage Journal
    Otherwise it would mean other non-predictable numbers could actually be predictable, potentially make breaking cryptography easier (much like finding out that a prime really isnt), would generally disrupt a bunch of mathematical theorems probably pissing off a whole sect of mathematicians, and turn a lot of things we think we know upside down.
  • Re:Well... (Score:5, Insightful)

    by Anonymous Coward on Wednesday August 19, 2009 @10:54PM (#29128507)

    I fail to see how not understanding the word "seems" is insightful.

  • by Anonymous Coward on Wednesday August 19, 2009 @10:58PM (#29128539)

    It's nothing to do with Pi. You can't even make a stick of exactly 1cm length.

  • by biryokumaru (822262) * <biryokumaru@gmail.com> on Wednesday August 19, 2009 @11:05PM (#29128585)
    To travel from one point to another, an object must pass through all the points in between. There are an infinite number of points "in between," thus to move at all, an object must travel through an infinite number of points in a finite time. Clearly this definition of reality is flawed: stop using it.
  • by Fluffeh (1273756) on Wednesday August 19, 2009 @11:14PM (#29128663)

    Of course it never repeats - we kind of knew that already.

    Goodness me, so many holes in this.

    Firstly, just because something isn't repeating doesn't mean there isn't a pattern.
    1,2,4,8 isn't repeating, but the pattern is there. (Each number doubles the previous)
    1,1.5,2.25,3.375 also doesn't repeat but there is a pattern.(Each number is the previous number plus half the previous number)

    Knowing (thinking) that something doesn't repeat and PROVING that it doesn't repeat are two ENTIRELY different things. I am guessing your maths/science education either stopped very early or you didn't do too well in either.

    If they found out there was a pattern, would I make a change in my life tomorrow? Nope. Am I glad they are actually doing something like this? Yes. Physics, chemistry and mathematics research fields are very much interested in "pure" research. However, the funding behind them generally has excellent applications in mind that we don't know about.

    So perhaps, rather than just mocking it and blowing it off, think back to all the other useless research done by people and what it has paid off. How about a simple transistor. Current goes one way, there are two ways out depending on an ON/OFF choice. Useless huh? Really useless. Can't think of a damn application for that at all.

  • Re:Well, (Score:3, Insightful)

    by east coast (590680) on Wednesday August 19, 2009 @11:31PM (#29128751)
    I'm glad there is more than one computer.

    Ever stopped to think that throwing more computing power at a problem is about as productive as throwing more money at a problem or more man power? You can only do so much before an effort becomes either redundant or the return on investment is as dismal as the stock market has been this past year.

    I don't honestly know what the practical value of knowing Pi to the 2.5 trillionth digit is but I'd like to think that there are enough resources in play that the fight for cancer isn't going to miss this one.
  • by sys.stdout.write (1551563) on Wednesday August 19, 2009 @11:39PM (#29128833)

    Knowing (thinking) that something doesn't repeat and PROVING that it doesn't repeat are two ENTIRELY different things. I am guessing your maths/science education either stopped very early or you didn't do too well in either.

    I think it's funny that you are insulting someone's math education immediately after you imply that no proof exists showing pi not to repeat.

  • by kipling (24579) on Wednesday August 19, 2009 @11:53PM (#29128919) Homepage

    So you are criticising my preparation for the afterlife? Other people memorise wodges of religious texts, I choose to memorise digits of pi ...

  • by Anonymous Coward on Wednesday August 19, 2009 @11:59PM (#29128963)

    Not necessarily. We can't really know about anything smaller than the Planck length, so in practical terms your paradox probably fails. The universe may be discrete on those scales.

  • by Dahamma (304068) on Thursday August 20, 2009 @12:29AM (#29129183)

    The grandparent post already answered that...

    PI = C/D

    Or even simpler: "PI is the circumference of a circle of diameter 1".

    Or how about "PI radians = 180 degrees"

    Just because it's not easily representable in a base-10 number system, doesn't mean you can't exactly define it.

  • by cryptoluddite (658517) on Thursday August 20, 2009 @12:30AM (#29129185)

    Because if there's a pattern in one base, there's a pattern in all bases. It's just maybe less obvious and easy to describe in some.

  • by commodoresloat (172735) * on Thursday August 20, 2009 @01:07AM (#29129415)

    They make a machine to take every job. Before I know it they'll have a machine loafing at the corner bar, smoking cigarettes and downing Jim Beam and Coke like it was water.

    I see you've met Bender.

  • by LS (57954) on Thursday August 20, 2009 @02:36AM (#29129837) Homepage

    The article isn't really that informative. It takes things too literally, using the known size of the universe to determine the largest possible physical circle and the smallest possible length (planck length) to determine the maximum precision and he comes up with 50 digits. But it wouldn't be too hard to come up with an application that uses more than 50 digits of pi. A new encryption algorithm could use sequences in pi, but this has nothing to do with physical circles. Math is abstraction, and there are fields in math that are so abstract that you can't even correlate them with a physical measure. It's very silly to say that knowing pi to more that 50 digits is useless.

    LS

  • by wickerprints (1094741) on Thursday August 20, 2009 @03:04AM (#29129973)

    It's a great way to test the performance of these supercomputers, to ensure that their calculations are correct. The calculation of pi to additional decimal places beyond what was previously known is never done with just a single method--otherwise, it is impossible to verify the additional digits. It is always done with two different algorithms to ensure that the result is valid. There are many rapidly converging algorithms (e.g., variations on AM-GM methods can be quadratically convergent or better; BBP-type digit extraction methods; and of course, classic Ramanujan series-type methods). However, computing pi to so many decimal places has much less to do with the chosen algorithm than it has to do with the memory- and computing time-efficient implementations of such algorithms in massively parallel architectures. Thus these calculations serve as very good tests for the robustness of supercomputers. The result is also verifiable to previously known digits, and even beyond the previous record, it is possible to perform statistical analyses to determine whether there are any significant deviations in the distribution of digit frequencies.

    So, in summary, it is hardly a useless computation. Not that you're going to get an explanation like this from your usual news sources, which generally do not write for technical audiences.

    Also note that distributed computing resources such as Folding@home, or even the Great Internet Mersenne Prime Search don't bother with calculating pi, as the purpose of these projects is to make new discovers in their respective fields of interest.

  • by MightyDrunken (1171335) on Thursday August 20, 2009 @05:07AM (#29130549)
    What's the pattern in base e? Cos I'm not seeing it.
    10.101002020002111....

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