Fast Fibonacci computation

Question

I saw a comment on Google+ a few weeks ago in which someone demonstrated a straight-forward computation of Fibonacci numbers which was not based on recursion and didn\'t use mem

Answer 1

From Wikipedia,

For all n ≥ 0, the number Fn is the closest integer to phi^n/sqrt(5) where phi is the golden ratio. Therefore, it can be found by rounding, that is by the use of the nearest integer function