Test Channel Ordering

Test Channel Ordering.ipynb

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   "cells": [
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "import numpy as np\n",
      "\n",
      "channels_last = np.random.random((150, 150, 40))\n",
      "channels_first = np.random.random((40, 150, 150))"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 1
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def gradient_channels_first(image_data):\n",
      "    g = np.empty((image_data.shape[0] * 2,) + image_data.shape[1:])\n",
      "    for i in xrange(image_data.shape[0]):\n",
      "        gx, gy = np.gradient(image_data[i])\n",
      "        g[2 * i] = gx\n",
      "        g[2 * i + 1] = gy\n",
      "    return g"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 2
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "def gradient_channels_last(image_data):\n",
      "    g = np.empty(image_data.shape[:2] + (image_data.shape[2] * 2,))\n",
      "    for i in xrange(image_data.shape[2]):\n",
      "        gx, gy = np.gradient(image_data[..., i])\n",
      "        g[..., 2 * i] = gx\n",
      "        g[..., 2 * i + 1] = gy\n",
      "    return g"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 3
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "%timeit gradient_channels_first(channels_first)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "100 loops, best of 3: 13 ms per loop\n"
       ]
      }
     ],
     "prompt_number": 5
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "%timeit gradient_channels_last(channels_last)"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "10 loops, best of 3: 22.7 ms per loop\n"
       ]
      }
     ],
     "prompt_number": 6
    }
   ],
   "metadata": {}
  }
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