SciPy (pronounced "Sigh Pie") is open-source software for mathematics,
science, and engineering.

The SciPy library is built to work with NumPy arrays, and provides many
user-friendly and efficient numerical routines such as routines for
numerical integration and optimization. Together, they run on all popular
operating systems, are quick to install, and are free of charge. NumPy
and SciPy are easy to use, but powerful enough to be depended upon by
some of the world's leading scientists and engineers.

umfpack is an optional dependency.  matplotlib and ipython are nice to 
have in connection with scipy, but scipy does not depend on them.

If you need to build scipy for debugging, set DEBUG=y.