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It's funny.  Laugh. Science

Happy Pi Day! 213

BlueCalx- writes "Today (March 14, 3-14-00) is Pi Day. ticalc.org has a feature on calculating pi and its origins. A search engine exists to search for a string of numbers in the first ten million digits of pi. And of course, there is the first million digits of pi. Eat pie, memorize pi, and watch Pi. I've got my day planned! "
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Happy Pi Day!

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  • by Anonymous Coward
    Celebrated pi-day a couple weeks ago!
  • Now that's offensive! Pi day is the third most important and sacred holiday of the year (besides, of course, Christmas and Easter).
  • Check out This [umd.edu] page if you'd like to make pi yourself on your home machine. The longest string the person writing the page knows of for a home computer is 256 million digits with a 400mhz pII. That took 3 days using version 2.2 of Carey Bloodworth's program [umd.edu].

    How far can you get?
  • I don't normally go in for pointless posts, but I figured I'd make an exception on this story just to show off my .sig.


    --Phil (And yes, I know that you don't care.)
  • I've said it before, and I'll say it again... Go to your favorite DVD seller and get Pi [pithemovie.com] right now. It's a very good movie with a very good story line. You won't regret it. And what better day than today to watch it. In fact, I think I'm going to watch it tonight when I get home. :)
  • Better form of the equation is:
    e^(pi * i) = 1 which unites all the constants we need to know about.
    --rama
  • Um, just curious why you didn't use the much more well known euler equation (is there anything in math euler didn't do?)

    e^(Pi*i) = -1

    Actually, in mathematics alot of equations are named after the _second_ person to use the equation to avoid naming everything after Euler.
  • I also use the YYYY-MM-DD format whenever I can (though I didn't know it was an ISO standard until a few months ago). It makes programming a lot easier when you can sort dates chronologically just by comparing their numeric value. Also it turns out that you can fit a code of the format YYYYMMDDnn (where 'nn' is an arbitrary 2-digit number) into a 32-bit integer. One place this is used is in the serial number for DNS records, as in:

    slashdot.org
    origin = slashdot.org
    mail addr = malda.slashdot.org
    serial = 2000022300
  • Are you kidding? This is as stupid as the "This is the last odd day for twelve hundred years!" story. Slashdot is supposed to be "News for Nerds", not "Numerology Tricks for Those Who Have Nothing Better To Do". Well, guess what? This is the last day the date will be 3-14-00 for a thousand years!! So is tomorrow! And yesterday! Three in a row!!! And wait 'till we hit 6-6-6.
  • This is my second pi day.

    Last year we went and figured out the error in the 100 digits of Pi that is carved in stone in Portland's Westbound light rail tunnel.

    And don't forget Pi approximation day. 7/22.
  • You sure? I could swear they tried to make it an even 3.

    Evidently in 2 Kings they describe an urn in Solomon's temple or something as being one cubit across and three around. That would make the ratio between the two 3.
  • is a club for those of us who love this number. Anyone with an interest in pi may become an associate member; we confer full membership on those who can recite -- respectfully and from memory -- the first 100 digits (base 10) after the decimal point (the last digit is '9').
    http://www.ast.univie.ac.at/~wasi/PI/pi_club.htm
    or
    http://www.ast.univie.ac.at/~wasi/PI/pi_klub.htm
    (German version).
  • Oopsie! That's:
    http://www.astro.univie.ac.at/~wasi/PI/pi_club.h tml
    and
    http://www.astro.univie.ac.at/~wasi/PI/pi_klub.h tml
  • >My boss is canadian and he writes his dates
    >year-month-day which struck me as a bit odd. Does
    >anybody know if this is common?
    I'm Canadian, and it's basically a whatever-you-like kind of thing in my part of the country (New Brunswick, Acadian peninsula). American culture is pretty dominant (this *is* North America, after all), but there's enough monarchists, and native french speakers, and first-generation immigrants that it's all pretty messed up. Fortunately, the bank tellers and cashiers here are quick enough to realize what a person means when they write 001504, 4/15/2000 or 15,04,00. I've seen all three, and many more, around here.

    Ever since discovering the Internet and finding that most technical people I've met use DDMMYYYY, I've always written it like that just to avoid confusion. Besides, it just makes sense. Smallest unit to largest unit.
  • The e is missing:

    http://www.pithmovie.com/

    vs

    http://www.pithemovie.com/

  • ...if you use proper ISO-8601 dates (YYYY-MM-DD). In fact, PI day will never occur at all. The closest you can get is PI year (3142 - rounding!).
  • I posted this story, including a link to the Exploratorium Pi Day Page [exploratorium.com], very early this morning, (read: 12:05am EST), and it was rejected. What are the criteria for posting these day? BTW: If you are in SF Bay area, definatly go to the Exploratorium, i was in CA last year and went, it was really fun.

    -mark
  • they _ARE_

    go to the site. (actually, its not that obvious, there is no year, but it does say 13th annual, and last year was the 12th)

    -mark
  • d'oh. Sorry, I'm an idiot.
  • How about 31/4/15?
  • My boss is canadian and he writes his dates year-month-day which struck me as a bit odd
    I noticed on my Canadian Tax return form that we write in the date YYYY-MM-DD.

    I've noticed that UK writers tend to hand-write dates as eg. 3rd March 1999, whereas USAer's and younger Canadians would tend to use March 3rd 1999.
    I believe I was taught in elemantary school to use the former, but all my digital watches display the date MM-DD, so that's how I started writing it. Then I moved to the USA for high school and fit right in.

    Now I'm back in Canada, and for my own uses and for the clock on my Mac, I use USA format: MM/DD/YYYY, but always use a leading zero for the Day, but not the Month, just in case.

    In any case, I notice most people say March 15, hence the use of MM/DD.

    Pope
  • Not quite. I think you meant

    e^(i*pi) + 1 = 0

    (to get both the additive and multiplicative identities in there).
  • This [aol.com] link is to Mike Keith's home page. Among other things, it has Poe's The Raven rewritten so the word lengths match the digits of pi, while keeping the style, rhythm and meaning of the original. It is later expanded into the Cadaeic Cadenza which is a masterpiece.
  • Anyone think we should be campaigning for a day off then? :-)

    Definitely. :-)

    Mnemonic for pi (from "Bluff your way in mathematics"):

    How I need a drink, alcoholic of course, after the heavy lectures involving quantum mechanics.

    (Count the letters in each word).

    The book claims that various obscene versions can be found on the walls of the lavatories in various maths or science departments. (Except at the Cavendish and DAMPT, where they have blackboards in the loos anyway, of course).

  • For most real applications, the notation log(x) is used to represent log base e. (Note: High School is not a real application.)
  • Wrong again.. The middle number's the month in the UK. We don't have a fourteenth month. =)

  • I had a development contract a while ago which involved the handling of data imports via Excel.

    The suppliers for the data used lots of different date formats and often entered dd/mm/yy data into an mm/dd/yy format sheet, thereby invalidating dates.

    I wrote a nifty algorithm which trends the dates on the sheet and makes a guess at the intended format. When you have a load of dates, you can quite easily work out what the date should be 99% of the time, even if the dates were entered incorrectly.

    Excel partly uses the separators (eg, whether a date is entered as 01/02/03 or 01-02-03) to determine the intended format.

    Starting in 2001, just under half of all dates expressed with two-digit years are going to be thoroughly ambiguous. This will last until 2012!
  • The other 4,000,000,000 digits of Pi are considered proprietary as they have great commercial value for decoding the Bible Code in the German King James edition...
  • Remember, the mammals have to be trained. Training occurs by repetition. :-)

    Actually, try to discuss Slashdot here [slashdot.org].

  • No no no, the last pi date Dec 15, 1979.
    At 9:27:45 pm, eastern time, to be exact.

    The next won't happen for quite a while.
  • That would make the PI minute: 3/14/15 9:26

    This is assuming we are using the U.S. notation of mm/dd/yy hh:mm for date/time format.

    Otherwise, using YYYY/mm/dd hh:mm you have to wait until the year May 9, 3141 for: 3141/5/9 to come around.

  • Does anyone know an algorithm for computing individual digits of the natural logarithm base constant (e)? I know the sum of one over n-factorial converges quickly to e but I don't know how to be sure of how many acutal digits are available at each step, and I imagine that there must be a computationally faster mechanism.
  • Don't believe me? In Indiana [urbanlegends.com], they (almost) did...

    Silly americans

  • Tiny! On this ftp server [u-tokyo.ac.jp] here they claim to have 4,200,000,000!! But only 200,000,000 for public download. BTW, they're at 6,442,450,000 PI digits now...

    What I don't get is: We know it is an irrational number so this is will go on forever. Is there any practical use to knowing PI with such precision or is it just a pissing contest among mathematicians?
  • search 10 million digits of pi [aros.net]
    download up to 51 billion digits of pi [u-tokyo.ac.jp]
    there's only 4.2 billion digits available for public download, but up to 51 billion can be downloaded by request (if you get them to email 51 billion digits to you, cc me ;>)
  • The value of e is approximately 2.71828182846. The problem is that the first two digits after the decimal point are "7" and "1". February 71??

    Use the European standard -- 27.1, i.e., 27 January.

    Remember how the Commodore 8-bit computers (PET, VIC 20, C-64, etc.) had the pi symbol right on their keyboard (shift + up arrow)

    Did? They're still there, even if the company isn't. Along with the monetary pound sign, which had an acquaintance of mine swearing up and down that clearly Commodore was a British company, and using rather charming circular logic (which I can't remember) to try to prove it. Oy.

  • by cje ( 33931 )
    And most things do seem to be after Euler. Some Gaussian. A whole wack of Cauchy (a touch of Dirichlet), some Euclidean, a splash of Newton, a touch of Taylor, and a jiggle of Riemann and Leibnitz.

    How dare you forget Georg Cantor??? :-)
  • If April actually had 31 days, that would be possible.

    Rob "30 days hath September..." Novak
  • Let's not forget Don McLean's seminal "American Pi" (often misspelt "Pie"). Lots of interesting info here [datasync.com].
    Although it's a bit out of date, since it fails to mention the Linux revolution, even though that is clearly mentioned in the song ("do you have faith in God above, if the Bible tells you so" is a clear reference to Linus...)
  • Here at the Math faculty of University of Waterloo, Ontario, we celebrated Pi Day with lots and lots of free pie (at 1:59pm of course!)

    I think Nortel Networks sponsored the event. You know you're in a geek-heaven university when...

    mmmm... bumbleberry pie... yum! :D

  • Hmmm. Most of the planks I've seen are oblong and therefore nothing to do with pi. They're also reasonably big, otherwise they'd be sticks, not planks.

    Perhaps you meant Planck? or perhaps I'm wrong.

    sorry. couldn't resist.
  • Contratulation to ticalc for getting one of their (often considered completely useless) features posted as a slashdot article! That's the first time I've seen one of those, and I've been following both sites for a pretty long time. ticalc.org is finally getting some recognition. For what? I'm not sure; the article was in the humor category.

    Anyway, why hasn't anyone posted with how many digits of pi they have memorized (like they have all over the ticalc page)? I must admit I can only do 31 from memory, which is a lot for most poeple, but not very much at all compared to some freaks. 231 was the most claimed so far on the ticalc.org page, 45 the most I've seen in person, and I believe the world record is over 40,000. Yes, that's 40,000.

    (There's no point in me posting the actual digits because there's no proof that I memorized them. The claim is just as valid as the digits, on a web forum.)
  • Funny tips on memorizing pi to 100 decimal places: http://au.4mg.com/pi.htm [4mg.com]
  • Actually, you'd have to wait until 3-14-16 by that logic; 3.14159... rounds to 3/14/16.

    Of course, the perfect Pi day would have been 3/14/1593, unless you want to wait a lonnng time and celebrate on 3/14/15926..! (ad nauseaum)

    Wheeee....
  • We celebrated PI day in school today also. Our's wasn't as extravagent though. We just wrote songs about PI and brought pies to eat in class. It was a lot of fun though.
  • I don't think I'll ever break a record, I once had 13 digits of Pi memorized, but now it's gone down to 10 :(

    Consider yourself lucky for having a weird memory :)


    _____________________
    .sig Instructions
    step one: place .sig here
  • What about 3-14-15926?

    Better start making plans...
  • We're supposed to have pie? Damn! and I just finished my pudding.
  • And here's some music for the younger geeks. Not mine, unattributed author on a home-schooling mailing list.
    >
    > THE PI SONG
    > (to the tune of "Oh Christmas Tree")
    >
    > Oh, number Pi
    > Oh, number Pi
    > Your digits are unending,
    > Oh, number Pi
    > Oh, number Pi
    > No pattern are you sending.
    > You're three point one four one five nine,
    > And even more if we had time,
    > Oh, number Pi
    > Oh, number Pi
    > For circle lengths unbending.
    >
    > Oh, number Pi
    > Oh, number Pi
    > You are a number very sweet,
    > Oh, number Pi
    > Oh, number Pi
    > Your uses are so very neat.
    > There's 2 Pi r and Pi r squared,
    > A half a circle and you're there,
    > Oh, number Pi
    > Oh, number Pi
    > We know that Pi's a tasty treat.
    >
  • The fact that this got marked "0, Troll" by the moderators can only be evidence that what it says is true. They mark it down to 0 so that readers with Threshhold 1 don't see it and still think that the fiefdom does not exist.
  • e^(Pi*i) = -1

    so, ie = the (Pi*i)th root of -i.

    Do we have an equation for netscape too?

    BTW, that i^(-i) equation doesn't seem to be correct, mainly because i^i is complex and the righthand side isn't. You can get to Euler's formula from that one, but not the other way around, so they aren't equivalent

  • I knew my .sig would be useful someday ;-)

  • No, that would be "Pi Approximation Day".
    --
  • I remember that key fondly. Whenever my brother and I were doing weird stuff on our Vic20, we didn't have a clue what that symbol was, so we called it 'the dog'. There was something really surreal about putting dogs in strings.

    Crazy.
  • Moderators !!

    Do your job and give a +5 Interesting to this guy

    Distributed computation of PI ? It has Distributed, Beowolf, Computing ... only Natalie Portman is missing from the scene ... :)

    • someone must port the software to Linux, *BSD, Mac, BeOS, HAL9000, PDP8 , fridges and toasters;
    • /. TEAM !!!
    • copyleft t-shirts with digits of pi ...

    go to http://www.cecm.sfu.ca/projects/pi hex/pihex.html [cecm.sfu.ca] NOW !

    ps: check out the guy's counter... the site will be /.ed in no time

  • Be warned:

    Communicator 4.7 x86 linux dies when the java part of "Pi the movie" is accessed.

    Don't know about other versions/platforms

  • The full story is told in Petr Beckman's A History of Pi [amazon.com]. The bill was stopped because of a chance visit by a local mathematician to the Senate floor. The bill wasn't killed, but rather tabled, and it simply hasn't been back on the agenda since.

    Dave Blau

  • Since .au uses the logical format of least significant to most significant, day, month, year.
    I think most to least is more logical, to match our base10 numbering system, but month, day, year is just not logical.

  • If I'm not mistaken doesn't most of the world use dd/mm/yy as their date format as opposed to the mm/dd/yy of north america? In which case 03/14/00 (or more accurately 03/14/15) will never come. Unless of course we add a few more months, which, in my opinion, is well worth it to have a day the whole world can enjoy.
  • It seems to me that since pi =~ 3.14159, that the real Pi day can only come along once per century. And the next one shoul be coming up March 14, 2016 (3-14-16). Or, better yet, we're a few centuries late: Seems the -real- pi day shoulda been 3-14-1592. And, of course, in 13,000 or so years, we'll possibly have 3-14-15926. Maybe if nanotech and virus-creation technology devlop fast enough, I'll live to see it. :)
  • Is there any practical use to knowing PI with such precision or is it just a pissing contest among mathematicians?

    An interesting question with an even more interesting answer. In a book by Petr Beckman, i think called "A History of Pi", he provides this example. The distance to the nearest star (proxima centauri) is a few lightyears (I think about 4 lightyears?) Suppose the sun and this star form a diameter of a huge sphere. Now further suppose this sphere is filled to the brim with tiny parameciums, I forget the size of these, but probably estimated as spherical at a few microns or so. Okay, you've now got a huge sphere teaming with googles of paramecia. Now let's take each paramecium and build a straight line with them, spacing each one apart by the few lightyears distance to proxima centauri. Such that you've now got an incomprehensibly large line out to intergalactic space. Now, suppose this incredibly huge line is the diameter of a circle, and the line's length is known to absolute precision. Thus, it is only the uncertainty of pi which prevents an accurate measure of the huge circle's circumference. If one knows pi to a mere 100 digits, the circumference can be calculated to a precision of a few microns!!!!!!!!!!!!!!!!!!!!!

    That is totally amazing, and crazy how quickly orders of magnitude can jettison out of our understanding. Basically, 10^100 is such a huge number, it would be an extraordinaly rare occurrance to need even close to this much precision. Note, I haven't checked the validity of these measurements, so they may be way off. But it's still something mind-numbing to think about!

  • Or going the other way, how much accuracy is needed to measure things on the scale of the entire universe?

    To avoid redundant redundancy, here is a to this same /. discussion but different thread (the 10,000,000 digits of pi thread), of an example of cosmological size, orders of magnitude, and how much precision of pi one may really need. [slashdot.org]

  • I'm looking forward to 3-14-15 at 9:26:53.59 in the morning. Seems like a much more accurate time / date that the others proposed.

    -Falcor
  • Robathome dun said (regarding someone's date of 31/4/15):

    If April actually had 31 days, that would be possible.

    Robathome no baka :)

    Seriously...different countries have different formats of splitting up dates and all. In the US, the typical format tends to be

    mm/dd/yy or mm/dd/yyyy

    where mm=month, dd=day, and yy=year (non-Y2K-compliant version) or yyyy=year (if you don't want to confuse hell out of everyone).

    Europeans do it different, like this:

    dd/mm/yy or dd/mm/yyyy

    where dd=day, mm=month, etc. etc.

    In much of Latin America, including Brazil (don't give me that shocked look--there are a lot of folks from Brazil on the net now, and even other countries like Mexico) they do it in yet another format:

    yy/mm/dd or yyyy/mm/dd

    where yy=year, etc. etc. etc.

    In fact, it's SO bad what with the confusion (not to mention that a lot of places, like, oh, damn near the entire Middle East, don't even USE the Gregorian calendar--and other places, like Japan, use it but with their own special "mutations" (in Japan, they have their own calendar year count--plus they tend to count by emperor's reigns, instead of calendar year)...) that there is actually an official ISO standard for references to dates--which, surprise, surprise, actually fits the Latin American standard: [cam.ac.uk]

    yyyy-mm-dd

    where yyyy=year, mm=month, etc.

    So he was right after all. So are the other folks. :)

    Myself, I think messing with numbers like that is a bother, so I just use dates like, oh, 15 April 31 (which was the date he mentioned, by the way--by that reckoning, Yshua of Nazareth might've gotten to see it, but we're almost two millennia late :) to be crystal clear. Or measure everything in the good, old, ACCURATE calendar that the Mayans used if I want to confuse hell out of everyone. :) (Which brings up an interesting point...the Maya knew about zero, probably knew about pi to make measurements, and the Long Count is actually measured in terms of base-20 increments...anyone know what pi would be in base 20 and what Pi Day would be in the Long Count? ;)

  • If you're referring to the basin described as "ten cubits across and thirty cubits in circumference" keep in mind that cubits aren't exact measures as feet/inches/meters are today. if you assume a cubit is about 18 inches, the difference between 30 cubits and 31.4 cubits is about 9 inches or so. this is about 5% error, which isn't extremely unreasonable.
  • My favorite has always been 355/113, it's a reasonably good approximation and it's easy to remember. Take the first three odd integers, duplicate the digits, cut in half and divide.
  • Here is a link that will lead you to several numbers like (Pi, e or the Golden Ratio) and how they were calculated http://www.lacim.uqam.ca/piDATA/ [lacim.uqam.ca]

    Here is a billion of decimals digits of Pi !!!! http://www.lacim.uqam.ca/piDATA/PI/ [lacim.uqam.ca]

    here is an explanation on they're latest record ... 206,158,430,000 digits .... http://www.lacim.uqam.ca/piDATA/pi 206billion.txt [lacim.uqam.ca]

    A lot of things to explore... and memorize
  • In sweden (And possibly other countries), the format of dates are year-month-day, thus it's a bit more accurate. Bad though that MAX_MINUTE=60, otherwise 00-03-14 15/92/65 would have existed...
    --The knowledge that you are an idiot, is what distinguishes you from one.
  • No, it was already past 408 years ago:

    3-14-1592

  • So whats up with the inaccurate 3.1428571
    I'm wondering if its just random typing or are you accually using an ancient version of the number
  • Geez I hate it when people open cans or worms. But anyhow without going into deep explanation, the hebrew language of old was very math based. All words had numeric values, and frequently sentences has either numeric of even equation meanings. Anyhow while I don't remember the exact figures and don't have time to look it up (but I bet you could) if one uses an exact interpretation, including the mathematical subtext the bible gives pi to be something along the lines of 3.1417. Still wrong, but as close as is resonable for building whatever they were making,
  • Not only is today Pi Day, it is also Albert Einstein's Birthday! Have a Relitivistic Day!

    By amazing coincedence, I was actually watching Pi [pithemovie.com] last night.

    "12:45, Restate my assumptions..."

    A wealthy eccentric who marches to the beat of a different drum. But you may call me "Noodle Noggin."

  • What makes you think you need 14 months?

    3rd January 2042 works nicely enough by the system they're suggesting here but I'd have to be picky and prefer the same day in 416 or 4159. Neither of which will, I suspect, have been or be seen by anyone in this forum.

    Not even Methuselah was _that_ old...

    Greg
  • pi = -2*i*ln(i) by definition.
  • I actually didn't know about it. :)

    And most things do seem to be after Euler. Some Gaussian. A whole wack of Cauchy (a touch of Dirichlet), some Euclidean, a splash of Newton, a touch of Taylor, and a jiggle of Riemann and Leibnitz.

    Mix together, and *poof*, one set of irrefutable truths.

  • i^i is complex and the righthand side isn't.

    Quite the contrary. i^(-i) is real. To quote Benjamin Peirce (Harvard Professor):

    "Gentlement, this is surely true, it is absolutely paradoxical, we can't understand it, and we haven't the slightest idea what the equation means, but we may be sure that it means something very important."
  • the correct fomula is in the subject... but it sucks... 'cause it converges really slowly.

  • pi = -2*i*ln(i) by definition.

    Yes. You can prove this easily using similar triangles. <cough, cough>

  • ... give or take a bit.
  • Whoops, here's the correct URL: Music based on Pi" [aol.com]
  • Right here [http]. Scroll down a bit for Pi, musical compositions based on pi (or down a little bit more for "Two Works"). No kidding. This is from an underground Seattle musician, so you'll be the only person in town with it :) I heard it a few years ago; tis good. Odd, yes, but good.
  • Those who are interested in Pi should check out Cadaeic Cadenza [aol.com]. It's a mnemonic for 3835 digits of Pi, and a decent novel too.

    In other words, someone had a talent for constrained writing and way too much time on his hands, and this is the result...
    --

  • 3.142856... is just a tiny bit closer to 3.14158 than 3.140000 is.
  • Or, if you're european, pi day should then be the 22nd of July? :)
  • The blurb pointed by FTP to uiarchive.uiuc.edu, one of the Project Gutenberg mirror sites. This only allows 100 simultaneous users, though.

    For the Project Gutenberg edition of the first 10K digits of Pi, try:

    http://metalab.unc.edu/gutenbe rg/etext93/pimil10.txt [unc.edu]

  • I don't think it's a pissing competition amongst mathematicians so much - there are already a large number of methods worked out to calculate pi - the simplest I can remember is pi/4 = 1 - 1/2 + 1/3 - 1/4 + 1/5 - ... but more amongst the people with large computers with spare time on their hands :)

  • There's a book called the "History of Pi" by Peter Beckmann. Click here [amazon.com] to find out more, if you're not boycotting Amazon or something like that. It's a fascinating read, not at all dull, and highly opinionated - he doesn't hesistate to dismiss groups of people as morons, like the Romans.
  • Happy pi day.

    This is the perfect occasion to spread the message of

    The Miraculous Baily-Borwein-Plouffe Pi Algorithm

    It is an algorithm to compute the n'th digit of Pi in any base, in
    particular it is possible to compute the n'th decimal digit without
    having to compute the n-1 first digits. This is a truly amazing
    result. We know that pi is irrational (Euler) and that pi is
    trancedental (Lindemann, 1982) and thus is highly irregular. That the
    n'th digit of pi is computable is therefore very surprising. There are
    only a countable number of computer algorithms and thus there are only
    countable any numbers that have the property that their n'th number is
    computable.

    On "Fabrice Bellard's Pi Page":

    http://www-stud.enst.fr/~bellard/pi/index.html#bin ary

    one can find an article that explains the algorithm together with an
    implementaion in c (two pages long). The remarkable thing is that the
    algorithm uses only normal integers and doubles. That is, one need not
    implement arbitrary precision arithmetic.

    The algorithm is new, 1996. In another thread the corresponding
    program is shown for base 16, but I much prefer the base 10 version
    :-)

    References:

    The original article concerning base 10 is

    "On the computation of the n'th decimal digit of various
    transcendental numbers." by Simon Plouffe, November 30, 1996.

    and can be found at

    http://www.lacim.uqam.ca/plouffe/Simon/articlepi.h tml

    History:

    A very readable account of the history of computations of pi is the

    "The quest for pi by Bailey, Plouffe and the Borweins." this can be
    found at

    http://www.lacim.uqam.ca/plouffe/Simon/TheQuestfor Pi.pdf

    Here they also answer why it is fun to compute many digits of pi. In
    the beginning the mathematicians wanted to know many digits of pi to
    find out whether pi was irrational or not. Euler showed that pi was
    irrational (the proof is not that hard). Later Lindemann in 1882
    showed that pi was trancedental, that is pi is root in no polynomial
    with integer coefficents. Today it is customary to compute many digits
    of pi on new super computers. In 1982 sun (?) actually found some
    obscure hardware bug due to a pi program.

    --
    Jens Axel Søgaard -- http://www.jasoegaard.dk

    A Mathematician is a machine for turning coffee into theorems.
    - Paul Erdös

  • The HREF pointing to the official movie site is broken; it in fact leads to http://www.pithmovie.com/" The trailing quote is interpreted as part of the URL and as such, simply 404's.

    Either put the beginning quote in or leave them both out, but at least match it up for those more inclined to click on links instead of typing (and/or fixing them).
  • According to this [go2net.com] article (c. 1995), Hiroyuki Goto, 21, captured the world record, reciting Pi to over 42,000 decimal places.
    I found it linked to from http://www.cecm.sfu.ca/PI/ [cecm.sfu.ca].
  • It's a shame that the Exploratorium [exploratorium.edu] isn't throwing another pi day [exploratorium.edu] this year. It was wonderful last year!
  • by Anonymous Coward on Tuesday March 14, 2000 @04:19AM (#1204299)
    private char nth_pi (int n) {
    // Bailey-Borwein-Plouffe Algorithm for arbitrary digit calculations.
    // only valid upto 2 ^ 24 for java IEEE precision.
    int loop; String Schx = "";
    double piFraction, s1, s2, s3, s4;
    char[] chx = new char[16]; int i,nhx; double y,x;
    char[] hx = {'0','1','2','3','4','5','6','7','8','9','A','B',' C','D','E','F'};
    s1 = series (1, n);s2 = series (4, n);s3 = series (5, n);
    s4 = series (6, n); piFraction = 4. * s1 - 2. * s2 - s3 - s4;
    piFraction = piFraction - (int) piFraction + 1.;x=piFraction;nhx=16; y = Math.abs(x);
    for (i = 0; i < 16; i++){
    y = 16. * (y - Math.floor (y));
    chx[(int)i] = hx[(int)Math.abs(y)];
    } for (loop=0;loop<16;loop++)
    Schx = Schx + chx[loop];
    return chx[0]; }
    private double series (int m, int n)
    /* sum_k 16^(n-k)/(8*k+m) */
    { int k; double ak, eps, p, s, t; eps = 0.00000000000000001;
    s = 0.;
    for (k = 0; k < n; k++){
    ak = 8 * k + m; p = n - k;
    t = expm (p, ak); s = s + t / ak;
    s = s - (int) s;}
    for (k = n; k <= n + 100; k++){
    ak = 8 * k + m;
    t = Math.pow (16., (double) (n - k)) / ak;
    if (t < eps) break;
    s = s + t; s = s - (int) s;
    } return s; }
    private double expm (double p, double ak)
    /* expm = 16^p mod ak. */
    { int i; int j; double p1, pt, r;
    if (tp1 == 0) {
    tp1 = 1; tp[0] = 1.;
    for (i = 1; i < 25; i++) {tp[i] = 2. * tp[i-1];}} if (ak == 1.) return 0.;
    for (i = 0; i < 25; i++) if (tp[i] > p) break;
    pt = tp[i-1];
    p1 = p;
    r = 1.;
    for (j = 1; j <= i; j++){
    if (p1 >= pt){ r = 16. * r; r = r - (int) (r / ak) * ak;
    p1 = p1 - pt; } pt = 0.5 * pt;
    if (pt >= 1.){ r = r * r;
    r = r - (int) (r / ak) * ak; } }
    return r; }

    and the following are global :

    static int tp1 = 0;
    static double[] tp = new double[25];
  • by Pete Bevin ( 291 ) on Tuesday March 14, 2000 @04:10AM (#1204300) Homepage
    Here is the correct FTP link to the 10,000,000 digits of PI: ftp://uiarchiv e.cso.uiuc.edu/pub/etext/gutenberg/etext93/pimil10 .txt [uiuc.edu]

    And here is an HTTP link: http://wuarchive.wustl .edu/doc/gutenberg/etext93/pimil10.txt [wustl.edu]

  • by Poe ( 12710 ) on Tuesday March 14, 2000 @04:26AM (#1204301) Homepage
    So there we were in Topology class. The class was being taught by the "Super Texas" method, which means we are given a few premises, and we work up an entire field of mathematics through proof. Each student had to prove things on the board in front of the other students. I said "OK let's take an irrational number...umm...Pi.." when suddenly, from the back of the class came "how do you know that Pi is irratoinal?" I spent the rest of the class proving it (off the top of my head, with much help from the professor). Needless to say, from then on, we used 1.01001000100001... or 2^.5 as our favorite irrational numbers.
  • by Get Behind the Mule ( 61986 ) on Tuesday March 14, 2000 @05:34AM (#1204302)
    In 1897, the state of Indiana nearly passed a bill decreeing that Pi is equal to 3.2 (it also said that sqrt(2) = 10/7). The bill unanimously passed the state House of Representatives (on a vote of 67-0), and went from there to the Senate. First it was referred to the Committee on Temperance, apparently as a joke, and the committee recommended approval. Then there was a floor debate in the Senate, full of puns and ridicule, in which all of the Senators who spoke admitted their ignorance on the merits of the bill. Importantly, they didn't kill it because it was a mathematical falsehood, but because the Senators thought they shouldn't be writing a law about something like that.

    There's a story about it [urbanlegends.com] on the urban legends site [urbanlegends.com]. Evidently, a crank mathematician named Dr. Edwin J. Goodwin M.D. "discovered" this new fact about Pi, and offered to let Indiana use it in their school textbooks without royalties if they passed the law. His state Representative bought into it and introduced the bill.

    I wonder if Kansas has any plans these days concerning Pi? :-)
  • by Anonymous Coward on Tuesday March 14, 2000 @04:22AM (#1204303)
    Pi? Why, I remember many years ago when I first heard the Story of Pi. I was just a little sprig of a troll, sitting on my grandfather's knee in our cozy little cave beneath the bridge. Oh, those were the days, when goats were plenty, the nights were long and hardly ever did the Karma Whores sell their warez by the river bank. And then there was pi . . .

    What?!?! You NEVER heard the Story of Pi? Well, sit down laddie! Grab yourself a fondue fork and I'll learn you REAL good.

    It all happened many many many many many years ago. Before I was born. Way back in the days of my granddaddy's poppa's great-grandfather's aunt's father's mother's granddad. The world was full of wonders even beyond my senile waxing. It was around this time that the Darkly Darkly wood was Open Sourced to all, and the knights of Slash ran amok spreading their Perl of Wisdom.

    There was one little troll, much like yourself, only not quite as stinky. He was named Bgialtels, and was the brother of my granddaddy's poppa's great-grandfather's aunt's father's mother's granddad. He was an angry little man, as most of us are, and wasn't happy with the Order of the Benevolent Single Druids, of which my granddaddy's poppa's great-grandfather's aunt's father's mother's granddad was a part. He thought that they must be distroyed, and so he came up with a plan.

    Bgialtels summoned demons at the annual Faeries Unified Dinner to run amok over the desert tables. At first everyone ignored them, even my granddaddy's poppa's great-grandfather's aunt's father's mother's granddad, but soon it became a problem. Action needed to be taken. After fourteen hours of havoc, my granddaddy's poppa's great-grandfather's aunt's father's mother's granddad placed upon the table 3.1428571 cherry pies in a carefully calculated place which made the demons slip into the flaming cheese fondue. Screaming in agony, the demons lashed out, managing only to take the final "e" off the word, leaving us with Pi.

    And that, my little friends, is where easter . . . I mean PI came from.

    thankyoutheend
  • by BaronM ( 122102 ) on Tuesday March 14, 2000 @04:07AM (#1204304)
    Shouldn't the declaration of Pi day wait until 3-14-15?
  • by debrain ( 29228 ) on Tuesday March 14, 2000 @04:39AM (#1204305) Journal
    Both e and Pi are not just irrational, but transendental, meaning they are not the product of algebraic systems, which was extremely difficult to prove. We shan't forget i either, the imaginary number, so aptly named (sarcasm).

    The interesting thing relating them would be:

    i^(-i) = e^(Pi/2)

    Yep. That's just bizarre. Nonetheless pretty much irrefutable in the complex number system.

    (anyone else notice how the sup tag doesn't work?)

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