{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "def factorial(n):\n",
    "    if n == 0:\n",
    "        return 1\n",
    "    else:\n",
    "        return n * factorial(n - 1)\n",
    "\n",
    "def fact_test():\n",
    "    for x in range(10000000):\n",
    "        i = factorial(10)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "3628800\n",
      "1 loop, best of 3: 18 s per loop\n"
     ]
    }
   ],
   "source": [
    "print(factorial(10))\n",
    "%timeit fact_test()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "%load_ext cython"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "%%cython\n",
    "\n",
    "def c_naive_factorial(n):\n",
    "    if n == 0:\n",
    "        return 1\n",
    "    else:\n",
    "        return n * c_naive_factorial(n - 1)\n",
    "\n",
    "def c_naive_fact_test():\n",
    "    for x in range(10000000):\n",
    "        i = c_naive_factorial(10)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "3628800\n",
      "1 loop, best of 3: 4.96 s per loop\n"
     ]
    }
   ],
   "source": [
    "print(c_naive_factorial(10))\n",
    "%timeit c_naive_fact_test()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "%load_ext cython"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "%%cython\n",
    "import cython\n",
    "cimport cython\n",
    "\n",
    "cdef int cfactorial(int n):\n",
    "    if n == 0:\n",
    "        return 1\n",
    "    else:\n",
    "        return n * cfactorial(n - 1)\n",
    "    \n",
    "cdef void cfact_test(int n):\n",
    "    cdef i, j\n",
    "    for i in range(10000000):\n",
    "        j = cfactorial(n)\n",
    "\n",
    "def fact_test(n):\n",
    "    cfact_test(n)\n",
    "        \n",
    "def factorial(n):\n",
    "    return cfactorial(n)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "3628800\n",
      "323 ms ± 1.48 ms per loop (mean ± std. dev. of 7 runs, 1 loop each)\n",
      "Approximately 50x improvement\n"
     ]
    }
   ],
   "source": [
    "print(factorial(10))\n",
    "%timeit fact_test(10)\n",
    "print(\"Approximately 50x improvement\")"
   ]
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python 3",
   "language": "python",
   "name": "python3"
  },
  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
   "version": "3.6.1"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 2
}