## Monday, December 6, 2010

### Math: At Which Point Does it Get Absurd?

In the ongoing game of "my computer is bigger and faster than yours" there seems to be one particular calculation that helps determine the winner of the game.

To calculate as many digits of pi as possible. Now I've mentioned pi before but not as something to calculate. One can never calculate pi exactly since it is a transcendental number. The decimal places keep going and going without repeating.

Which makes it a perfect number to calculate on computers because you can keep calculating it for as long as you like. There is no built in limit to how many digits you can compute.

Computing pi by hand is tedious and error prone. Nevertheless over time people sat down and did the calculations. Starting in 1947 or so computers also cranked out digits. Here is a short chronology of the number of digits calculated over time. This list ends in 1999 with a computer calculating 206 billions digits.

Eleven years later that number has been surpassed and not by a little bit. The current record for the number of calculated digits of pi is.... 5 trillion. That's 5,000 billions or 5 million million digits -(5,000,000,000,000).

Better yet it wasn't calculated on a supercomputer nor on a cluster of specialized machines nor on a specially built computer. It was calculated on a desktop computer in 90 days.

Granted it was a fully loaded desktop computer. The specs are within the reach of anyone with lots of cash and access to a computer store:

• 2 Intel Xeon processors (12 cores total)
• 96 GB of memory
• 19 x 2 TB disks and 1 x 1 TB disk
And it ran Windows Server. Given similar (or better) hardware and a bit more time maybe you an calculate a new record yourself.

The story of the calculation, with details, some pictures, and access to the program that did the calculation is all here.

After years of these types of calculations being done on supercomputers and specialized machines it's interesting to note that home computers have progressed this far. I wonder who's taken up the challenge to calculate a few extra trillion digits? I wonder if somewhere there's another high end typical computer cranking away to set a new record.

#### 1 comment:

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