Pi-obsessed Japanese reach 2.5 trillion digits

A Japanese supercomputer has calculated the value of pi to more than 2.5 trillion decimal places, more than double the previous record set in 2002.

Daniel Terdiman/CNET

It's funny how the Japanese love to waste their supercomputers on climate change and car design instead of nuclear weapons like in some countries.

Now they're squandering their teraflops chasing down irrational numbers.

The T2K-Tsukuba System, a supercomputer at the University of Tsukuba northeast of Tokyo, has calculated the value of pi to more than 2.5 trillion decimal places, a record. The old record of more than 1.2 trillion decimal places was set in 2002 by a team from the University of Tokyo and Hitachi.

The new value of pi is 2,576,980,370,000 decimal places long, the result of a computation on T2K-Tsukuba in April of this year that took 73 hours and 36 minutes. The time included verification.

The T2K-Tsukuba consists of 640 nodes with peak calculation of 95.4 trillion floating point operations per second.

"If there is an error in any part, the calculation would be impossible," associate professor Daisuke Takahashi of the Center for Computational Sciences was quoted as saying by the Yomiuri newspaper. "I think the result shows the high reliability of the system."

Takahashi, who wrote the two programs that performed the calculation, applied to Guinness World Records earlier this month with the new value.

He noted some intriguing numerical sequences in the result, including 012345678901, 987654321098, 8888888888888, and even 3141592653589.

As I've written elsewhere, Japan has been losing the supercomputer race for some time now, so I think further pi brinkmanship among Japanese labs is unlikely. But you never know. There may be a computer in Kyoto or Osaka cooking up a 10 trillion-digit pi.

The populace would sure eat it up. Back in 2005, 59-year-old Akira Haraguchi recited pi to an astonishing 83,431 decimal places.

Haraguchi wasn't crazy. His job? Mental health counselor.

 

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