{
 "metadata": {
  "name": "",
  "signature": "sha256:1c79cf627e3e56fbb004a7c9a265a12aab13c938a743ac0498b3f0dac24f1a6c"
 },
 "nbformat": 3,
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 "worksheets": [
  {
   "cells": [
    {
     "cell_type": "markdown",
     "metadata": [],
     "source": [
      "> This is one of the 100 recipes of the [IPython Cookbook](http://ipython-books.github.io/), the definitive guide to high-performance scientific computing and data science in Python.\n"
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "# 4.3. Profiling your code line by line with line_profiler"
     ]
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "Standard imports."
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "import numpy as np"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "After installing `line_profiler`, we can export the IPython extension."
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "%load_ext line_profiler"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "For `%lprun` to work, we need to encapsulate the code in a function, and to save it in a Python script.."
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "%%writefile simulation.py\n",
      "import numpy as np\n",
      "\n",
      "def step(*shape):\n",
      "    # Create a random n-vector with +1 or -1 values.\n",
      "    return 2 * (np.random.random_sample(shape) < .5) - 1\n",
      "\n",
      "def simulate(iterations, n=10000):\n",
      "    s = step(iterations, n)\n",
      "    x = np.cumsum(s, axis=0)\n",
      "    bins = np.arange(-30, 30, 1)\n",
      "    y = np.vstack([np.histogram(x[i,:], bins)[0] for i in range(iterations)])\n",
      "    return y"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "Now, we need to execute this script to load the function in the interactive namespace."
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "import simulation"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "Let's execute the function under the control of the line profiler."
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "%lprun -T lprof0 -f simulation.simulate simulation.simulate(50)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "print(open('lprof0', 'r').read())"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "Let's run the simulation with 10 times more iterations."
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "%lprun -T lprof1 -f simulation.simulate simulation.simulate(iterations=500)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "print(open('lprof1', 'r').read())"
     ],
     "language": "python",
     "metadata": {},
     "outputs": []
    },
    {
     "cell_type": "markdown",
     "metadata": {},
     "source": [
      "> You'll find all the explanations, figures, references, and much more in the book (to be released later this summer).\n",
      "\n",
      "> [IPython Cookbook](http://ipython-books.github.io/), by [Cyrille Rossant](http://cyrille.rossant.net), Packt Publishing, 2014 (500 pages)."
     ]
    }
   ],
   "metadata": {}
  }
 ]
}