fibonacci series what Iam is missing ?

[Steven D'Aprano]

On Tue, 24 Mar 2015 03:16 am, Chris Angelico wrote about the standard
recursive version of the Fibonacci series:

> On Tue, Mar 24, 2015 at 3:01 AM, Ganesh Pal <ganesh1pal at gmail.com> wrote:

>> def fib(n):
>>     if n == 0:
>>         return 0
>>     elif n == 1:
>>         return 1
>>     else:
>>         return fib(n-1) + fib(n-2)


> 2) Your algorithm is about as hopelessly inefficient as it could
> possibly be, barring deliberate intent.


It is pretty inefficient, but it is a good toy example of recursion. It's
also a good example of how *not* to write the Fibonacci series in practice,
what is mathematically straightforward is not always computationally
efficient.

The question is, just how inefficient is is? How many calls to `fib` are
made in calling fib(n)?

Answer to follow.



-- 
Steven