SymPy is a Python library for symbolic mathematics. It aims to become
a full-featured computer algebra system (CAS) while keeping the
code as simple as possible in order to be comprehensible and easily
extensible. SymPy is written entirely in Python and does not require
any external libraries.

Optional dependencies are pyglet (needed only for plotting) and ipython.

Please read https://github.com/sympy/sympy/wiki/Release-Notes-for-0.7.0 
for backward compatibility issues with sympy 0.6.x.