Arbitrary precision arithmetic with GMP

Question

I\'m using the GMP library to make a Pi program, that will calculate about 7 trillion digits of Pi. Problem is, I can\'t figure out how many bits are needed to hold that many de

Answer 1

2^10 = 1024, so ten bits will represent slightly more than three digits. Since you're talking about 7 trillion digits, that would be something like 23 trillion bits, or about 3 terabytes, which is more than I could get on one drive from Costco last I visited.

You may be getting overambitious. I'd wonder about the I/O time to read and write entire disks for each operation.

(The mathematical way to solve it is to use logarithms, since a number that takes 7 trillion digits to represent has a log base 10 of about 7 trillion. Find the log of the number in the existing base, convert the base, and you've got your answer. For shorthand between base 2 and base 10, use ten bits==three digits, because that's not very far wrong. It says that the log base 10 of 2 is .3, when it's actually more like .301.)