Fibonacci number benchmark

fibonacci.js

// fibonacci(40) takes 2 seconds in Node.js 0.6.14

// http://en.wikipedia.org/wiki/Fibonacci_number

function fibonacci(n) {
  return n < 2 ? n : fibonacci(n-2) + fibonacci(n-1);
}

fibonacci.php

// fibonacci(40) takes 60 seconds in PHP 5.4.0
// fibonacci(40) takes 21 seconds in PHP 7

function fibonacci($n) {
  return $n < 2 ? $n : fibonacci($n-2) + fibonacci($n-1);
}

fibonacci.py

# fibonacci(40) takes 42 seconds in Python 3.2.2

def fibonacci(n):
	return n if n < 2 else fibonacci(n-1) + fibonacci(n-2)

fibonacci.ruby

# fibonacci(40) takes 18 seconds in Ruby 1.9.3

def fibonacci(n)
  n < 2 ? n : fibonacci(n-1) + fibonacci(n-2)
end