Fabrice Bellard told AFP he used an inexpensive desktop computer — and not a supercomputer used in past records — to calculate Pi to nearly 2.7 trillion decimal places.<\/p>\n
That is around 123 billion digits more than the previous record set last August by Japanese professor Daisuke Takahashi, he said.<\/p>\n
Takahashi, using a T2K Open Supercomputer, took 29 hours to crunch Pi to 2.577 trillion digits.<\/p>\n
Bellard took 131 days, comprising 103 for the computation in binary digits, 13 days for verification, 12 days to convert the binary digits to a base of 10 and three final days to check the conversion.<\/p>\n
The gear cost “a bit less than 2,000 euros” (3,000 dollars), Bellard, who earns a living as a software consultant in digital television in Paris, said in an email exchange.<\/p>\n
“It is a completely standard PC. The only unusual thing is that it has five 1.5-terabyte hard disks. Mainstream PCs generally have only one 1-terabyte disk.”<\/p>\n
Bellard has placed on his website details of the achievement, including the use of a high-powered mathematical engine called the Chudnovsky algorithm that chewed through the computation.<\/p>\n
Extracts of the 2,699,999,990,000-digit outcome have been published so that they can be compared to preceding records in order to gain independent verification, Bellard told AFP.<\/p>\n
Files containing the digits are also being offered to any outside organism keen on hosting the record, he said.<\/p>\n
Pi, the ratio of a circle’s circumference to its diameter, kicks off with 3.14159… in a string whose digits are believed never to repeat or end.<\/p>\n
Bellard said he was “not especially interested” in Pi’s digits but more in taking up the gauntlet of writing the software to carry out the arithmetic.<\/p>\n
“Optimising these algorithms to get good performance is a difficult programming challenge,” he wrote.<\/p>\n