January 6, 2010

Computer Scientist Sets New Record For Calculating Pi

Computer scientist Fabrice Bellard said he has computed the mathematical constant pi to nearly 2.7 trillion digits, some 123 billion more than the previous record, BBC News reported.

Bellard used a desktop computer to perform the calculation, taking a total of 131 days to complete and check the result. He said his version of pi takes over a terabyte of hard disk space to store.

Bellard also claims his method is 20 times more efficient than previous records established using supercomputers.

Daisuke Takahashi at the University of Tsukuba in Japan took just 29 hours in August 2009 to set the prior record of about 2.6 trillion digits.

But Takahashi's accomplishment came with the aid of a supercomputer that is 2,000 times faster and thousands of times more expensive than the desktop Bellard used.

Ballard made his computations using part of a branch of mathematics known as arbitrary-precision arithmetic "“ which basically means knowing a given number to any amount of decimal places.

To show how long the currently determined pi is; reciting one number a second would take more than 85,000 years.

Bellard told BBC News he got his first book about Pi when he was 14 years old and since then he has followed the progress of the various computation records.

"I am not especially interested in the digits of pi. Arbitrary-precision arithmetic with huge numbers has little practical use, but some of the involved algorithms are interesting to do other things," he said.

While he plans to release a version of the program he used to do the calculation, Bellard said that carrying on with any further billions of digits "will depend on my motivation".

The result is just the latest in a long quest for a longer pi, according to Ivars Peterson, director of publications at the Mathematical Association of America.

Peterson said Newton himself worked on the digits of pi and spent a lot of time using one of the formulas he developed to get a few extra digits.

However, in modern times, pi has served as more than just a simple but lengthy constant.

"People have used it as a vehicle for testing algorithms and for testing computers; pi has a precise sequence of digits, it's exactly that, and if your computer isn't operating flawlessly some of those digits will be wrong," he explained.

"Pi is a way of testing a method and then the method can be used for other purposes," Peterson said.


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