Pi chart. As this log chart shows, computations of pi have grown by 9 orders of magnitude, from 2037 to 1.241 trillion digits, in 53 years.

Pi in the Sky

The precision of pi has passed the trillion-digit mark--a sixfold increase over the previous record. Yasumasa Kanada and colleagues at the University of Tokyo recently announced the completion of a calculation of 1.241 trillion digits of mathematicians' favorite constant, 3.14159…

Kanada is the world's unquestioned pi king these days--he and his team have set virtually all the records since the mid-1980s. Their last one, in 1999, reached 206 billion digits. The latest calculation took over 400 hours on a Hitachi supercomputer. The programs for doing all the high-precision arithmetic, Kanada reports, were 5 years in the making. To nail down their result, the group actually computed pi with two different formulas.

What insights do all these digits offer? Not many, says David Bailey, a mathematician at Lawrence Berkeley National Laboratory, who computed a then-record 29 million digits in 1986. Pi primarily provides a convenient benchmark for measuring machines' ability to juggle huge numerical data sets quickly and accurately.

Related sites
Kanada's Web site
Computing Pi
More Pi pages on the Web

Posted in Math