.. _virtualenv_title:

Installation without root access
===================================

Probably, these instructions are restricted to Linux and/or Mac users.

If you don't have root access to your computer but you still want to install
additional packages, you can do so by using a virtual environment. You need
to have a basic Python installation for this, and some (but remarkably few)
packages need additional non-python packages. Unfortunately, matplotlib is one
of these.

Everything
below is based on `this blog <http://dubroy.com/blog/so-you-want-to-install-a-python-package/>`_.

    1. Download `the latest version version of virtualenv.py <https://raw.github.com/pypa/virtualenv/master/virtualenv.py>`_
      to some location (it really doesn't matter where).

    2. Create a base Python environment, e.g. in the directory ``~/venv/base`` (but you can use another too)::
    
        $:> python virtualenv.py ~/venv/base
       
       This command will create a virtual environment that has access to all the
       installed packages on your system but allows you to install other packages.
       If you want a totally clean Python environment, you can do so by replacing
       the previous command with::
           
        $:> python virtualenv.py --no-site-packages ~/venv/base
        
    3. Make sure your system finds the new Python executable, by either typing the following line
      each time you want to use Phoebe, or add it to your ``~/.profile`` or ``~/.bash_profile``::
        
        $:> source ~/venv/base/bin/activate
        
    4. You now have access to pip, so you can install the required dependencies.
      If they are already installed, but you want a newer version, add the
      option ``--upgrade`` after ``install``. This will not touch your system
      installation, but will install a new version in your virtual environment::
        
        $:> pip install numpy
        $:> pip install scipy
        $:> pip install ipython