{
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    {
      "execution_count": null, 
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      "source": [
        "%matplotlib inline"
      ], 
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    }, 
    {
      "source": [
        "\nPlotting a vector field: quiver\n================================\n\nA simple example showing how to plot a vector field (quiver) with\nmatplotlib.\n\n"
      ], 
      "cell_type": "markdown", 
      "metadata": {}
    }, 
    {
      "execution_count": null, 
      "cell_type": "code", 
      "source": [
        "import numpy as np\nimport matplotlib.pyplot as plt\n\nn = 8\nX, Y = np.mgrid[0:n, 0:n]\nT = np.arctan2(Y - n / 2., X - n/2.)\nR = 10 + np.sqrt((Y - n / 2.0) ** 2 + (X - n / 2.0) ** 2)\nU, V = R * np.cos(T), R * np.sin(T)\n\nplt.axes([0.025, 0.025, 0.95, 0.95])\nplt.quiver(X, Y, U, V, R, alpha=.5)\nplt.quiver(X, Y, U, V, edgecolor='k', facecolor='None', linewidth=.5)\n\nplt.xlim(-1, n)\nplt.xticks(())\nplt.ylim(-1, n)\nplt.yticks(())\n\nplt.show()"
      ], 
      "outputs": [], 
      "metadata": {
        "collapsed": false
      }
    }
  ], 
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      "display_name": "Python 2", 
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