# Pi Day

March 14, 2014

Pi Day is a world-wide annual celebration commemorating the mathematical constant π (pi).

One of the reasons why the IRMACS Centre celebrates Pi Day is that Dr. Peter Borwein, the Founding Director of the IRMACS Centre, has had a long standing interest in the number Pi. Here are a few details that illustrate how Dr. Borwein's work is linked with the most famous of all numbers. Dr. Borwein, his brother Jonathan, and Dr. David Bailey of NASA co-wrote the 1989 paper demonstrating how to compute one billion digits of pi. This paper was awarded the 1993 Chauvenet and Hasse prizes for expository writing. In 1995, the Borweins and Dr. Yasumasa Kanada of the University of Tokyo, took pi to over four billion digits. That same year, working with Dr. Bailey and Dr. Simon Plouffe, now at the University of Quebec, Dr. Borwein developed an algorithm known as the BBP (Bailey-Borwein-Plouffe) formula to calculate the individual hexadecimal digits of pi. In other words, they were able to arrive at the nth digit of pi without calculating all the preceding digits. (By the way, the quadrillionth binary digit of pi is 0.) In 1999, Dr. Borwein co-authored the book "Pi: A Source Book".

The current record as of December 28, 2013 is 12 trillion decimal digits calculated by Alexander J. Yee and Shigeru Kondo.

Why compute the digits of Pi? In Dr. Borwein's words:  "Sometimes it is necessary to do so, though hardly ever more than six or so digits are ever really needed. Whatever the personal motivations, π has been much computed and a surprising amount has been learnt along the way. The computation of Pi seems to stretch the machine and there is a history of uncovering subtle and sometimes not so subtle bugs at this stage."

## Friday, March 14, 2014 11:30-12:20 IRMACS Presentation Studio, ASB 10900 Dr. Veselin Jungic, Department of Mathematics & The IRMACS Centre presents "Pi Day Trivia: An Experiment"

Bring your laptop or other wireless device to participate!

Pie-a-la-mode will be served at 12:20