## Nicholas Sze of Yahoo Finds Two-Quadrillionth Digit of Pi 299

Posted
by
timothy

from the I'm-a-good-guesser-in-binary-too dept.

from the I'm-a-good-guesser-in-binary-too dept.

gregg writes

*"A researcher has calculated the 2,000,000,000,000,000th digit of pi — and a few digits either side of it. Nicholas Sze, of technology firm Yahoo, determined that the digit — when expressed in binary — is 0."*
## Re:So, what is the digit in decimal? (Score:3, Informative)

We only know how to calculate it in binary (or any base that is a power of 2). You can't convert to decimal without know all the rest of the digits.

## Re:You fail math forever (Score:2, Informative)

## Re:You fail math forever (Score:3, Informative)

101-5

110-6

111-7

## Re:So, what is the digit in decimal? (Score:5, Informative)

We only know how to calculate it in binary (or any base that is a power of 2). You can't convert to decimal without know all the rest of the digits.

Parent is correct, digits of pi can be calculated independently in base 2, 4, 8, 16 or 2^n since the 1990s [maa.org]. So, it is possible to calculate the 2,000,000,000,000,000th number of pi without calculating the digits before that one. Now, if we want to calculate the digit in decimal (or converse the binary digit to decimal), we need to calculate all of the two-quadrillion digits. Knowing this digit is in itself not very interesting.

## Re:The interesting thing about this article is how (Score:3, Informative)

At least with regards to calculating Pi, it's isn't particularly new. They first used this parallel method back in the 1980's.

## Re:how do they do it (Score:3, Informative)

Regardless of what actually happened, there isn't any computation that requires keeping data in memory rather than hard disk. Memory is just faster, if you need more space for the computation, you can always actually use the 100 disks.

## Re:Oh yeah? (Score:1, Informative)

You're wrong, because TFA is discussing the binary representation of pi. It's either a 1 or a 0.

## Re:Last Digit? (Score:4, Informative)

Pi is NOT irrational! It is transcendental. Look it up!

http://en.wikipedia.org/wiki/Transcendental_number [wikipedia.org] :

All real transcendental numbers are irrational, since all rational numbers are algebraic.

## Re:an so are an infinite other digits in that numb (Score:4, Informative)

The hexadecimal digit extraction formula for PI (that allows you to skip calculating the previous hex digits) is already known. It can calulcuate the N'th hexadecimaldigit of Pi without calculating most of the previous digits: http://en.wikipedia.org/wiki/Bailey%E2%80%93Borwein%E2%80%93Plouffe_formula [wikipedia.org]

A slower generalized version that can extract the n'th digit of Pi in any base (including decimal) has also been found: http://web.archive.org/web/19990116223856/www.lacim.uqam.ca/plouffe/Simon/articlepi.html [archive.org]

## Re:an so are an infinite other digits in that numb (Score:3, Informative)