Pi --

Researchers in Japan have calculated pi to over 2.5 trillion decimal places, more than double the previous world record set in 2002.

Led by University of Tsukuba professor Daisuke Takahashi, the research team performed the calculation using a massive parallel processing (MPP) supercomputer called the T2K Tsukuba System, which consists of 640 high-performance computers clustered together to achieve processing speeds of 95 teraflops (95 trillion floating-point operations per second). The supercomputer calculated pi to 2,576,980,377,524 decimal places in 73 hours 36 minutes.

By comparison, it took the previous record holders about 600 hours to perform their calculation (over 8 times longer than it took the T2K Tsukuba System). The previous record was set in 2002 when researchers from Hitachi and the University of Tokyo calculated pi to a little over 1.2 trillion decimal places.

The University of Tsukuba researchers, whose stated primary objective was to test the reliability and speed of their supercomputer, have submitted their results to the Guinness Book of World Records for official recognition.

[Sources: Asahi, Yomiuri]