Pymbolic is a small expression tree and symbolic manipulation library. Two things set it apart from other libraries of its kind:

• Users can easily write their own symbolic operations, simply by deriving from the builtin visitor classes.
• Users can easily add their own symbolic entities to do calculations with.

Pymbolic currently understands regular arithmetic expressions, derivatives, sparse polynomials, fractions, term substitution, expansion. It automatically performs constant folding, and it can compile its expressions into Python bytecode for fast(er) execution.

If you are looking for a full-blown Computer Algebra System, look at sympy or PyGinac. If you are looking for a basic, small and extensible set of symbolic operations, pymbolic may well be for you.

Resources:

• documentation
• download (via the package index)
• source code via git (also bug tracker)