I used Yahoo's Hadoop clusters to compute the 1,000,000,000,000,001st bit of π. The 7 hexadecimal digits of π starting at the 10^15+1 bit are:
Although Hadoop is primarily used for data-intensive applications, it can also be used to run CPU-intensive jobs on many machines. Computing a range of bytes in π using a BPP-type formula, requires a lot of arithmetic operations and therefore CPU, but not much storage. When computing the 10^15+1st bit of π, the first 30% of the computation was done in idle slots of our Hadoop clusters spread over 20 days. The remaining 70% was finished over a weekend on the Hammer cluster, which was also used for the petabyte sort benchmark.
This validates the results calculated by PiHex, which took more than 2 years on 1734 computers from 56 different countries.
My program was written entirely in Java and ran on Hadoop 0.20. An earlier version is checked in as a Hadoop example named BaileyBorwinPlouffe. The new code will be uploaded soon.
-- Tsz Wo (Nicholas), Sze