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Blue Gene/P Reaches Sixty-Trillionth of Pi Squared
Reader Dr.Who notes that an Australian research team using IBM's Blue Gene/P supercomputer has calculated the sixty-trillionth binary digit of Pi-squared, a task which took several months of processing. Snipping from the article, the Dr. writes: "'A value of Pi to 40 digits would be more than enough to compute the circumference of the Milky Way galaxy to an error less than the size of a proton.' The article goes on to cite use of computationally complex algorithms to detect errors in computer hardware. The article references a blog which has more background. Disclaimers: I attended graduate school at U.C. Berkeley. I am presently employed by a software company that sells an infrastructure product named PI."
From the blurb:
Oh, I expected the sentence to end with, "...and I still don't know why the fuck anyone cares about a number this long."
I'm going to the bar. Who's with me?
What does that number "do"?
Pi is famous, and the more well known number to crunch. Why crunch Pi Squared? Can't you just square Pi?
My first Journal Entry ever, in 8 years! http://slashdot.org/journal/365947/aphelion-scifi-fantasy-horror-poetry-webzine
http://www.toothpastefordinner.com/031208/how-many-digits-of-pi-do-you-know.gif
So they just calculated that one binary digit?
Was it a 0 or an 1?
The Tao of math: The numbers you can count are not the real numbers.
"Disclaimers: I attended graduate school at U.C. Berkeley. I am presently employed by a software company that sells an infrastructure product named PI.""
That's *not* a DISCLAIMER. That's a DISCLOSURE.
...neither TFA nor TFBlog tell you which it is. So...flip a coin.
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Yes really, why squared? I prefer mine round. Atm I feel like pumpkin would be best.
Well within it, actually.
1.67E-13 is FAR larger than 2^-6E13. Stupid math.
The only surefire protection against Microsoft infections is abstinence. - The Onion
Is there the equivalent to pi in three dimensions? I mean, the ratio of a sphere's surface area to the area of the circular plane bisecting it? Maybe it has no significance.
That number is 4
Well, three dimensions are just more rational. :-)
The Tao of math: The numbers you can count are not the real numbers.
Why not compute digits of e? What's all this obsession with pi? For me, this time it's personal.
... enough to compute the circumference of the Milky Way galaxy to an error less than the size of a proton
Why bother carrying out the computation to such precision when the error in your measurement of the radius (or diameter) would be so much bigger.
Life's a tale told by an idiot, full of sound and fury, signifying nothing.
Not square.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
Wow, a BlueGene/P is being used to run something other than Linpack. That's gotta be a first.
Disclaimer: I didn't attend graduate school at U.C. Berkeley, nor am I presently employed by a software company that sells an infrastructure product named PI. I have, however, wasted way too much time trying to get codes to build and run (slowly!) on BG/* platforms.
But there might be a circle in there.
http://michaelsmith.id.au
It's plain easy to calculate the sixty-trillionth digit of Pi... as long as you don't care about the digits that come before it: http://www.sciencenews.org/sn_arc98/2_28_98/mathland.htm.
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I know the last digt of pi! It's zero... in base pi.
HSJ$$*&#^!#+++ATH0
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Only kind of. Ever hear about the Gauss Bonnet theorem? In a curved space, the value of Pi still matters.
You humans and your base-10 arithmetic. I use base-pi arithmetic. So pi = 1, and pi squared = 1. Computed in a nanosecond. Of course, it makes other computations slightly more complex. For example, I have about 3.183095825842514 fingers, more or less...
solid angle
Give me 10 attempts and I guarantee I can guess this digit faster than the computer can compute it.
Of course, this being slashdot, I didn't RTFA.
Question: Knowing the diameter of the observable universe, how many digits of Pi are needed to calculate the circumference of the observable universe, accurate to within 1 plank length?
Answer: 62 digits. Here they are: 3.14159265358979323846264338327950288419716939937510582097494459
Calculated this one myself.
Yeah, because it's so hard to calculate 2*pi given pi (to how ever ma).y decimal places.
I think it would be tremendously funny to find out, at some suitably ridiculous decimal place, that all subsequent places are zero repeating. It would utterly break some people's heads to find out that the number is only "very, very particular," rather than "irrational."
It is the one hope that holds my interest when I read about crunching these numbers.
Pi = 3
YTMND inspired a lot of people to learn more digits of Pi. "Pi" by Hard n Phirm became a minor fad there.
There is a sequence of several 9's fairly early in the decimal expansion of pi though. People have joked about memorizing pi out to 770 digits so they can say "...999999 and so on."
But seriously, the irrationality of arctan(1) (which equals tau/8 or pi/4) has been proven.
'A value of Pi to 40 digits would be more than enough to compute the circumference of the Milky Way galaxy to an error less than the size of a proton.'
I freaking love mathematicians. Everything has a proof when you can't actually prove it, coming or going.
Everyone knows PI squared is ten.
What IS the sixty trillionth digit of Pi? That's what I'd like to know.
Wasn't that value set in the bible long before?
The Tao of math: The numbers you can count are not the real numbers.
1. Starting at the 60 trillionth binary decimal place, pi^2 is, in base 8, 601145053032. Expanding to base 2 this is 110 000 001 001 100 101 000 101 011 000 011 010. You can see more at this post on a blog run by David Bailey and Jonathan Borwein of BBP-type formula fame.
+1 Contact reference
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The surface area of a sphere is (4/3)*pi*r^3. The area of a circle is pi*r^2. Dividing the former by the latter gives (4*pi*r^3)/(3*pi*r^2), which simplifies to (4 * r) / 3, or (4/3) * r. So... no, except in so far as the area of the sphere is defined as a pi-using function of it's radius. Unsurprisingly the ratio of surface area to cross-sectional area is increased when scaling, to the frustration of many a hollywood monster.
No, it's not. See my other post.
A small region of space is sufficiently flat for practical use, in the same manner that a flat map can be used to show a small region of the surface of the earth with low enough error to permit navigation.
The bible value is three exactly. It's actually detailing the exact size of a ceremonial container: Circular, ten cubits across, thirty around (Big). The 0.1 discrepency is simply because they didn't measure very precisely at the time, and rounded as convenient. It still bothers a few people who have trouble accepting that something made to the design of God could be so sloppily and imperfectly built, so there are a few religious traditions that explain it as esoteric code. Most just accept it as rounding error.
There is no error at all, those are the correct number of whole cubits. You'd have the same issues if the measurement were given to a 0.001 of a cubit. Those who claim some error are ignorant of the concepts both of accuracy and precision.
Pi can be digitized in an infinite number of representations, your post contains one of them. You promote an ignorance of mathematics.
But the Goodyear Dealer still won't believe me when I show them my tire is out of round.- Go figure
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Surprised EVERYONE.
Fail! That would be a surface area expressed in cubic meters?! I'm not a huge fan of dimensional analysis, but here it could have given you a clue that something was not quite right. What's the formula for the volume of a sphere again? A tip if you're having trouble remembering the formulas for volume and surface area of a sphere: the latter is the derivative of the former. O, and unsurprisingly the ratio between two surface areas of an object does not change with uniform scaling. Most Hollywood monsters know this, of course. Now go ahead and apologize. Twice ;-)
Yes it is. See my reply to your other post ;-)
Yes, I got the formula mixed up - I was using one for volume rather than surface area, which should be 4*pi*r^3. Simplifying to a ratio of four. I'm not sure where you got the bit about 'cubic meters' from though - all the units I used were unspecified. The math would work in meters, feet or cubits. I should have picked up on the mistake when I saw the r^3, rather than the ^2 you'd expect of an area, but by then was too intent on the algebra that followed.
I stand corrected. Sorry about that, got the formula for area and volume mixed up.
I said meters because most scientists prefer SI units, but of course it could have been cubic feet, cubic chains, cubic light years, cubic shackles, or any other weird unit. But cubic anything can never be a unit of area.
I still managed to put ^3 rather than ^2. I used to actually be good at this math stuff.