From April 28, 2021 to August 14, 2021, a server system of the Center for Data Analysis, Visualization and Simulation (DAViS) of the University of Applied Sciences Graubünden, Switzerland, calculated decimal places of the circle number Pi. The result was a presumably new world record with 62.8 trillion decimal places, more precisely 62,831,853,071,796, which occupy 63 TB of storage space.
“Presumably” because the result still has to be checked independently. That Team around IT project manager Thomas Keller and center manager Prof. Dr. Heiko Rölke But don’t worry: With the help of the two formulas Bailey-Borwein-Plouffe and Bellard, they double-checked their values themselves. The result has already been sent to the Guinness Book Review Center, which will probably need one to four months for verification.
Currently Timothy Mullican holds the world record with 50 trillion decimal placescalculated over 303 days. If the new result is correct, the last ten known digits of Pi are 7817924264.
y-cruncher for help
The Graubünden University of Applied Sciences also used the y-Cruncher software for the calculation, which determines decimal places based on the Chudnovsky algorithm. Pi is an irrational and transcendent number. Means: The number Pi can neither be represented as a fraction (irrational) nor as a polynomial (transcendent) – there are an infinite number of decimal places.
The calculation of the decimal places is used as a benchmark. The way is the destination, as it were, because the accuracy of pi no longer has any practical use.
AMD processors and lots of memory
The Swiss team used two AMD Epyc 7542 processors for the calculation. The two 32 CPU cores themselves didn’t have a lot of work to do – rather, with y-cruncher, the memory and its transfer rate limit. The calculations per se ran in 1 Tbyte DDR4 RAM, but the values were written continuously and in parallel with 8.5 GByte / s on a data carrier in order to free up the working memory.
For reasons of cost and durability, a total of 38 hard drives with a capacity of 16 TByte each were used: 34 in RAID-0 for the ongoing calculations (swapping) and 4 for the final storage. The swapping ultimately required 310 Tbytes of storage space, while intermediate results took up 180 Tbytes.
y-cruncher ran on the Linux operating system Ubuntu 20.04, which was installed on an SSD. The team made some optimizations to speed up the calculations through the program.