What is the maximum recursion depth in Python, and how to increase it?

Question

I have this tail recursive function here:

def recursive_function(n, sum):
    if n < 1:
        return sum
    else:
        return recursive_function(n-1         


        

Answer 1

Of course Fibonacci numbers can be computed in O(n) by applying the Binet formula:

from math import floor, sqrt

def fib(n):                                                     
    return int(floor(((1+sqrt(5))**n-(1-sqrt(5))**n)/(2**n*sqrt(5))+0.5))

As the commenters note it's not O(1) but O(n) because of 2**n. Also a difference is that you only get one value, while with recursion you get all values of Fibonacci(n) up to that value.