title: import matplotlib.pyplot as plt, ImportError: libGL.so.1: cannot open shared object file: No such file or directory
body: <p><code>import matplotlib.pyplot as plt</code> is erroring with python2.7, anaconda3.</p>
  
  <p>The error is <code>ImportError: libGL.so.1: cannot open shared object file: No such file or directory</code></p>
  
  <p><strong>Error report</strong></p>
  
  <pre><code>Traceback (most recent call last):
    File "&lt;string&gt;", line 1, in &lt;module&gt;
    File "/serving/anaconda3/envs/python27/lib/python2.7/site-packages/matplotlib/pyplot.py", line 115, in &lt;module&gt;
      _backend_mod, new_figure_manager, draw_if_interactive, _show = pylab_setup()
    File "/serving/anaconda3/envs/python27/lib/python2.7/site-packages/matplotlib/backends/__init__.py", line 32, in pylab_setup
      globals(),locals(),[backend_name],0)
    File "/serving/anaconda3/envs/python27/lib/python2.7/site-packages/matplotlib/backends/backend_qt5agg.py", line 16, in &lt;module&gt;
      from .backend_qt5 import QtCore
    File "/serving/anaconda3/envs/python27/lib/python2.7/site-packages/matplotlib/backends/backend_qt5.py", line 26, in &lt;module&gt;
      import matplotlib.backends.qt_editor.figureoptions as figureoptions
    File "/serving/anaconda3/envs/python27/lib/python2.7/site-packages/matplotlib/backends/qt_editor/figureoptions.py", line 20, in &lt;module&gt;
      import matplotlib.backends.qt_editor.formlayout as formlayout
    File "/serving/anaconda3/envs/python27/lib/python2.7/site-packages/matplotlib/backends/qt_editor/formlayout.py", line 56, in &lt;module&gt;
      from matplotlib.backends.qt_compat import QtGui, QtWidgets, QtCore
    File "/serving/anaconda3/envs/python27/lib/python2.7/site-packages/matplotlib/backends/qt_compat.py", line 128, in &lt;module&gt;
      from PyQt5 import QtCore, QtGui, QtWidgets
  ImportError: libGL.so.1: cannot open shared object file: No such file or directory
  </code></pre>
  
  <p><strong>conda list is</strong></p>
  
  <pre><code>$conda list
  cairo 1.14.8 0 defaults
  certifi 2016.2.28 py27_0 defaults
  cycler 0.10.0 py27_0 defaults
  dbus 1.10.20 0 defaults
  expat 2.1.0 0 defaults
  fontconfig 2.12.1 3 defaults
  freetype 2.5.5 2 defaults
  functools32 3.2.3.2 py27_0 defaults
  glib 2.50.2 1 defaults
  gst-plugins-base 1.8.0 0 defaults
  gstreamer 1.8.0 0 defaults
  harfbuzz 0.9.39 2 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
  icu 54.1 0 defaults
  jpeg 9b 0 defaults
  libffi 3.2.1 1 defaults
  libgcc 5.2.0 0 defaults
  libgfortran 3.0.0 1 defaults
  libiconv 1.14 0 defaults
  libpng 1.6.30 1 defaults
  libxcb 1.12 1 defaults
  libxml2 2.9.4 0 defaults
  matplotlib 2.0.2 np113py27_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
  mkl 2017.0.3 0 defaults
  numpy 1.13.1 py27_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
  openssl 1.0.2l 0 defaults
  pandas 0.20.3 py27_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
  pango 1.40.3 1 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
  patsy 0.4.1 py27_0 defaults
  pcre 8.39 1 defaults
  pip 9.0.1 py27_1 defaults
  pixman 0.34.0 0 defaults
  pycairo 1.10.0 py27_0 defaults
  pyparsing 2.2.0 py27_0 defaults
  pyqt 5.6.0 py27_2 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
  python 2.7.13 0 defaults
  python-dateutil 2.6.1 py27_0 defaults
  pytz 2017.2 py27_0 defaults
  qt 5.6.2 5 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
  qt5 5.3.1 1 dsdale24
  readline 6.2 2 defaults
  scikit-learn 0.19.0 np113py27_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
  scipy 0.19.1 np113py27_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
  setuptools 36.4.0 py27_1 defaults
  sip 4.18 py27_0 defaults
  six 1.10.0 py27_0 defaults
  sqlite 3.13.0 0 defaults
  statsmodels 0.8.0 np113py27_0 https://mirrors.tuna.tsinghua.edu.cn/anaconda/pkgs/free
  subprocess32 3.2.7 py27_0 defaults
  tk 8.5.18 0 defaults
  wheel 0.29.0 py27_0 defaults
  zlib 1.2.11 0 defaults
  (python27)
  </code></pre>