Setting up an environment vs setting up a known good environment

The env folder contains files to help get you setup using a consistent environment with all packages specified.

The requirements_py[27|36].txt files contains a list of required python packages and known working versions for each. They differ from the dependencies_py[27|36].txt files in the root directory in that those files specify packages and version ranges, rather than exact versions, to allow conda to resolve dependecies and pull updated versions.

Of course, the environment really needs more than just python packages, while pip only manages python packages. The conda environment files, conda_environment_py[27|37]_[osx64|i686].yml files can be used to create conda environments with exact versions of all the packages for python 2.7 or 3.6 on OS X or linux. This is the most reliable way to recreate the entire environment.