Derivator.ipynb

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   "cells": [
    {
     "metadata": {},
     "cell_type": "heading",
     "source": "Exercise for the course [Python for MATLAB users](http://sese.nu/python-for-matlab-users/), by Olivier Verdier",
     "level": 2
    },
    {
     "metadata": {},
     "cell_type": "code",
     "input": "%pylab\n%matplotlib inline\nfrom __future__ import division",
     "outputs": [],
     "language": "python",
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    {
     "metadata": {},
     "cell_type": "markdown",
     "source": "A numerical derivative of a function $f$ is a formula of the type\n\\\\[\nf'(x_0) \\simeq \\frac{f(x_0+h/2) - f(x_0-h/2)}{h}\n\\\\]"
    },
    {
     "metadata": {},
     "cell_type": "markdown",
     "source": "Implement a function `derivator` which returns the derivative *function*."
    },
    {
     "metadata": {},
     "cell_type": "code",
     "input": "def derivator(f, h):\n    pass",
     "outputs": [],
     "language": "python",
     "trusted": true,
     "collapsed": false
    },
    {
     "metadata": {},
     "cell_type": "code",
     "input": "msin_ = derivator(cos, 1e-10)",
     "outputs": [],
     "language": "python",
     "trusted": true,
     "collapsed": false
    },
    {
     "metadata": {},
     "cell_type": "code",
     "input": "assert(allclose(msin_(0), 0))\nassert(allclose(msin_(pi), 0))\nassert(allclose(msin_(pi/2), -1.))",
     "outputs": [],
     "language": "python",
     "trusted": true,
     "collapsed": false
    }
   ],
   "metadata": {}
  }
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