bofh453-cos-timing.ipynb

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   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
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   "source": [
    "from __future__ import division"
   ]
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  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
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   "outputs": [],
   "source": [
    "import numpy as np\n",
    "import numba as nb"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
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   "source": [
    "A = np.random.random((60000000,))\n",
    "B = np.random.random((60000000,))"
   ]
  },
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    {
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     "text": [
      "1 loops, best of 3: 2.3 s per loop\n"
     ]
    }
   ],
   "source": [
    "%timeit np.cos(A) * np.cos(B)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1 loops, best of 3: 2.99 s per loop\n"
     ]
    }
   ],
   "source": [
    "%timeit (np.cos(A + B) + np.cos(A - B)) / 2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
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   "source": [
    "@nb.jit(nopython=True)\n",
    "def unreduced_expr(A, B):\n",
    "    return np.cos(A) * np.cos(B)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1 loops, best of 3: 1.76 s per loop\n"
     ]
    }
   ],
   "source": [
    "%timeit unreduced_expr(A, B)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "@nb.jit(nopython=True)\n",
    "def reduced_expr(A, B):\n",
    "    return (np.cos(A + B) + np.cos(A - B)) / 2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1 loops, best of 3: 1.93 s per loop\n"
     ]
    }
   ],
   "source": [
    "%timeit reduced_expr(A, B)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": []
  }
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