March 14th (= 3/14) is Piday !!!
Happy Piday to everyone !
I hope that you will celebrate and promote the spirit of Pi in your classroom or at home (or your office !). Send me your pictures. Best ones will be published on this page, like every year. Here is a nice song ! And on the right are some pies realized last year, see piday.fr. There will be a show tonight in La Criée in Marseille, France, by the way.
Hello everyone !
Finally, this French website has been translated into English !! Yeahhh ! Many many thanks to Florian Bouyer (first prize), David Jelgersma, Guillaume (Bobest3g), Thomas Robitaille and myself ;). Since some (all) of these translators were not Englishnative speakers, I have to ask you to be VERY tolerant regarding the quality of English. If you have time and if you like these pages, any help to correct the English would be very much appreciated, please contact me.
Also, be aware that
50% of the content of pi314.net is more than 10years old, at a time when the web was still mostly in version 1.0 and when Google had just achieved its first round of equity funding. Thus, this website has to do neither with advanced interfaces nor with blogging, twittering, facebook, Wikipedia or others social modern ideas. Pi314.net is just a personalized collection of 170 pages about the most wonderful number in the universe (to me... no, it really is): Pi. In other words, let's forget about the soulless Pi's page of Wikipedia !! :) (ok, all right, I like it all the same but it's depressive, isn't it ?)
In this website, you will find here and there some numbers like Axxxxxx which refer to the great website of Neil Sloane : Encyclopedia of Integer Sequences.
For instance, you can find Pi's digits here A000796.
Finally, Pi Lovers are encouraged to write and propose new pages on Pi ! Most recent ones by myself have been written using a LaTeX template ( LaTeX template, LyX 1.3 template, about LyX) then converted by Tex4ht from LaTeX to HTML. Thus, in a nutshell, you can send me a LaTeX file with something nice or fun about Pi and roughly following the above template and I will include it in the website (with your name of course) after having converted it. See for instance a page from a great guy with lots of good ideas.
Pi news !
Remember that in december 2009, Fabrice Bellard broke a new Pirecord: the greatest number of digits computed on a personal computer (2700 billions !!). See here the details about this wonderful record ! Well, this record was broke by Alexander J. Yee & Shigeru Kondo on 2010, august 2nd with 5000 billions ! See here the announce and here for details. Well, as a personel computer, it is a monster (see on right) with 12 cores, 96GB of memory and 39TB of hard drive storage. Not exactly the personal computer of everyone...
I still can't believe it but I finally published a research paper on Pi with Jesús Guillera ! :
Construction of binomial sums for π and polylogarithmic constants inspired by BBP formulas, Appl. Math. ENotes, 7(2007), 237246.
News of the website
 I'm looking for people correcting and improving the english on this website. If you like this website and even have a few minutes, thank you in advance for your help. 
 Again, a new algorithm from Benoit Cloitre in an Archimedes fashion !!
 A new algorithm from Benoit Cloitre in a continued fraction fashion
 New pages Links, Bibliography and Poems entirely as databases. Thus, you can leave comments and propose your own poems, links or books !
Who are you, dear visitor ?? (11695 votes from a previous poll)
A mathematician (don't be modest) (1519) 
13.0% 
An undergraduate in maths (2283) 
19.5% 
Well, say, I just like maths (2132) 
18.2% 
I'm in high school (2069) 
17.7% 
Pi and its legend are fun to me (1700) 
14.5% 
My hobby is more about history, computer programming or music... (470) 
4.0% 
A webaddict, that's all (650) 
5.6% 
I just ran into this website unexpectedly (514) 
4.4% 
Ooops, this is not where I wanted to arrive ! (358) 
3.1% 
Sitemap
If this is the first time you're visiting (or even if you're used to come !) it is possible that you are confused with my messy website... Innovation (absolutely...), I made a sitemap available in order to access the wanted webpage quickly ! If you're looking for a given word, do not hesitate to use the search engine at the top of this window
Around the website 







(Pi, site, me) 




Whenever I have time, some personal thoughts (likely in french) 







Get pages from the website 








The narcissistic page 








fifteen minutes of glory (in french) 















Mathematics 

History 
of Pi of course ! 


Mathematicians 





Al Kashi 
Geometry 



Archimedes 
Geometry 



Bellard 
BBP Formula 



J. and P.Borwein 
Ultra fast Algos Ramanujan's formulas 


Brounker 
Continued Fractions 



Brown 
Number theory 



Buffon 
Needle's problem, probabilities 



G. et D. Chudnovsky 
Ramanujan's like formulas 



Cesaro 
Probabilities 



Cues 
Geometry 



Descartes 
Geometry 



Estenave/Fretigny 
Sums. Residuals theorem. 


Euler 
Sums 



Fibonacci 
Fibonacci sequence 



Fourier 
How to prove Euler's sums 


Gauss 
Machin like formula 



Gosper 
Strange sums and formulas 


Huvent 
Hypergeometric sums 


Katahiro 
Geometry 



Lambert 

Pi is irrational 



Leibniz 

A simple sum 



Lindemann 

Pi is a transcendental number 



Machin 

A famous sum 



Mandelbrot/Bolle/Edgar 
Fractals and Pi 



Moivre/Stirling 
Stirling's formula 



Newton 

Inverse sinus sum 



Plouffe 

BBP formulas 



Ramanujan 
Incredible formulas 



Salamin/Brent 
Ultrafast algorithm 



Viete 

Geometry 



Wallis 

Infinite product 



Woon 

Formula 


All formulas 




Geometrybased 
Antiquité  16e siècle 



Analysisbased 
17e siècle  19e siècle 



Modern algorithms 
20e siècle 


Numerical approximations 



Softwares 





PiFast 3.2 





PiAGM 





Macintosh 





Windows 





Linux 





UNIX 





Sun 





BeOS 





OS/2 





Amiga 





CGI 





SourcesC 





TurboPascal 




Classes Java 




Calculatrices 




Librairies 




Misc and personal formulas 




Lots of formulas ! 





Hypergeometrical sums 




Randomnessrelated phenomena 
Probability theorems, Brownian motion 



Complexity 
Normal numbers, randomness 



Pi's digits and statistics 
Fractal dimension, tests on digits, Khintchin's constant 



Personal ideas 
BBP sums 



Chebychev's polynomials 
Sums 



Spigot's algorithm 
How to compute Pi digits by hand 



The Attic 

Mixture of unexpected formulas for Pi 



C(n,k) Triangle 
Counting 



Arithmetic functions 
Gauss, Euler, Moëbius, Zeta 



New stuff with old stuff ! 
Improvement of Archimede's formula. By Benoît Cloitre 



A Xmas formula for Pi 
by Benoit Cloitre 



e and Pi in a mirror 
Two symetrical formulas for e and Pi ! by Benoit Cloitre 



Pi and Log(2) in a mirror 
Two continued fractions for Pi and Log(2) by Benoit Cloitre 


Maths definitions 





Bernoulli's numbers 


Digits 










Methods used in Pi digits computing 



Aitken's Delta2 
Fasten formulas 



Newton's algorithm 
Extract roots 



nth digit of a number 
How to use BBP formulas 



Fast Fourier transform 
How to multiply two large integers efficiently 


Computation records 




Graph of records 




nth digit record (base 2) 
Use of BBP formulas 



Continued fractions 




Memory of digits 




Records announcements 




Record 04/99 (68m) 
Details on the record 



Record 09/99 (206m) 
same 



Record 12/2002 (1241m) 
same 



Statistics on Pi's digits 
Frequency of digits 



1m digits: text (HTML) 
1 million digits 



Download (stuffit) 
1 million digits 



Download (zip) 
1 million digits 

The world of Pi 

Poems 

Poems on or from Pi 


Papers/videos 





Research papers 




Papers from magazines 




Talks/presentation 




Videos Simon Plouffe 




Interview RTL (french) 



Delirium ! 





Poll 





Anecdotes about mathematicians 



Anecdotes about Pi 




Short Pi quizz 
Test your knowledge about Pi 


Tough Pi quizz 
Same 



How many digits do you know ? 


Piday 
International day of Pi ! 


Images/Wallpapers 
About Pi of course 


Music 
Pi in music 



Links about Pi 




Bibliography 
Books to have 

Vote for this website !
Already Pilovers have come on this website since 06/20/99 !
Boris Gourévitch
/ CNPS Lab, CNRS, Université of Orsay, Paris XI, France
* Last changes :
Some stuff for Piday 2013  Digits in a classroom  Update of the Piday Page  The English version !! Everything is new in english ;)
* Coming next:
Many corrections in english and updates of links, biblio, poems, music and so on...
