17 Sep 2010

Pi calculation more than doubles old record

9:46 am on 17 September 2010

A researcher at the internet giant Yahoo has calculated the number pi to its two-quadrillionth digit, more than doubling all previous records.

Pi is the ratio of a circle's circumference to its diameter. It cannot be expressed exactly as a fraction, and consequently its decimal representation never ends or repeats.

The researcher, Tsz Wo Sze, calculated the number in 23 days, using a thousand computers - the equivalent of 500 years' work on a single machine.

The pursuit of longer versions of pi is a long-standing pastime among mathematicians, the BBC reports.

But this approach was very different from the full calculation of all of the digits of pi - the record for which was set in January at 2.7 trillion digits.

Instead, each of the computers was working on a formula that turns a complicated equation for pi into a small set of mathematical steps, returning just one, specific piece of pi.