Finding the closest fibonacci numbers

Question

I am trying to solve a bigger problem, and I think that an important part of the program is spent on inefficient computations.

I need to compute for a given number N, th

Answer 1

You can use the closed-form expression of the fibonacci numbers.

Since the second term in it is very small, you can approximate it with just the first term, so n can be found with base-golden ratio logarithm.