Bigger slices of pi.

The effort to determine the numerical value of pi (the ratio of a circle's circumference to its diameter) has now reached 2.16 billion decimal digits. Using their own custom-built, desktop computer, mathematicians David V. and Gregory V. Chudnovsky of Columbia University in New York City arrived at this number in the course of an extensive search for subtle mathematical patterns that may lurk among the digits of pi. Setting a new world record, their computation more than doubles the number of digits available for scrutiny (SN:9/9/89, p.166).

Using an advanced supercomputer and a more conventional mathematical approach than that taken by the Chudnovskys, Yasumasa Kanada of the University of Tokyo reached 1,073,740,000 decimal digits in November 1989. Kanada says that if he can obtain access to a suitable supercomputer for a long enoung period, he may be able to extend his computation of pi to at least 1.5 billion decimal digits.