Pi calculated to ‘62.8 trillion digits’ with a pair of 32-core AMD Epyc chips, 1TB RAM, 510TB disk space

Switzerland’s University of Applied Sciences Graubünden has challenged the world record for calculating Pi, claiming it has computed the mathematical constant to 62.8 trillion digits.

The university yesterday claimed it had broken the record, asserting it beat the previous record of 50 trillion digits, held by Timothy Mullican, by 12.8 trillion digits, and did it 3.5 times faster.

Helpfully, the uni has also published details of the hardware used for its feat.

A pair of 32-core AMD Epyc 7542 processors powered the uni’s rig. AMD states the CPU cores spend most of their time at 2.9GHz, can burst to 3.4GHz, have 128MB L3 cache and happily run 64 threads apiece. A server with 1TB of RAM was also employed, with Ubuntu Linux 20.04 installed on a pair of solid-state disks of unspecified size.

A JBOD housed 38 7200RPM hard disks, each with 16TB capacity.

Thirty-four of those disks were used to store values swapped from RAM – a design chosen because memory is very expensive. Hard disks were chosen over SSDs because SSD performance degrades over time and the university’s designers feared their intensive calculations could cause problems. In all, the uni said 510TB of disk space was used.

The uni’s rig was modest compared to the cloudy 96-vCPU effort that Google employed to calculate Pi to 31.4 trillion decimal places in 2019.

An app called y-Cruncher did the work, and was configured to move data in parallel from the server to the 34 disks at around 8.5GB/sec.

Sharp-eyed readers will have noted that the JBOD housed 38 disks – the other four were used to store the value of Pi itself.

The last ten digits stored on those disks are 7817924264 and they are now the last known digits of Pi, if the uni’s calculations are correct. If the world record is confirmed by Guinness, the full number will be published, the uni said. ®

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