anchor.diff:    libpng-devel freetype-devel \
     hdf5-devel \
     netcdf-devel \
  -  libyaml-devel
  +  libyaml-devel tkinter
   
   # Install system-indepedent python environment
  -RUN virtualenv /opt/python
  +RUN virtualenv /opt/python && \
  +  mkdir -p /opt/ipython && \
  +  chown -R researcher /opt/python /opt/ipython
  +
  +USER researcher
   
   # Install from PIP
   # - Notebook dependencies
  
positive.code:   /opt/python/bin/pip install git+git://github.com/pytables/pytables@develop
  
  # Install NLTK
  RUN yum install -y tkinter && \
    /opt/python/bin/pip install nltk pyyaml
  
  # Create IPython profile, then
  # install MathJAX locally because CDN is HTTP-only
  RUN mkdir -p /opt/ipython && \
    IPYTHONDIR=/opt/ipython /opt/python/bin/ipython profile create default && \
    /opt/python/bin/python -c "from IPython.external.mathjax import install_mathjax; install_mathjax()" && \
    chown -R researcher /opt/python /opt/ipython
  
  # Add supporting files (directory at a time to improve build speed)
  COPY etc /etc
  
negative.code: # - Readline for usability
  # - Useful IPython libraries
  # - Missing IPython dependency
  RUN source /opt/python/bin/activate && \
    pip install --upgrade setuptools==9.1 && \
    pip install \
      tornado pyzmq jinja2 \
      ipython \
      pyreadline \
  