Numpy average

gistfile1.txt

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   "cells": [
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     "cell_type": "code",
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     "input": [
      "import numpy as np\n",
      "np.version.full_version"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
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       "output_type": "pyout",
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     "input": [
      "a = np.ones(1000000, dtype=np.int16) * 500\n",
      "\n",
      "mask = np.random.randint(0, 2, a.size)\n",
      "b = np.ma.masked_array(a, mask=mask)\n",
      "\n",
      "np.average(b), np.mean(b), np.ma.average(b), np.ma.mean(b)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
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       "text": [
        "(500.0, 500.0, 500.0, 500.0)"
       ]
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     "input": [
      "a = np.ones(10000000, dtype=np.int16) * 500\n",
      "\n",
      "mask = np.random.randint(0, 2, a.size)\n",
      "b = np.ma.masked_array(a, mask=mask)\n",
      "\n",
      "np.average(b), np.mean(b), np.ma.average(b), np.ma.mean(b)\n"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
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       "text": [
        "(500.0, -359.51019673027423, -359.51019673027423, -359.51019673027423)"
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     "prompt_number": 3
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     "cell_type": "code",
     "collapsed": false,
     "input": [
      "b = b.astype(np.float64)\n",
      "np.average(b), np.mean(b), np.ma.average(b), np.ma.mean(b)"
     ],
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       "text": [
        "(500.0, 500.0, 500.0, 500.0)"
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