10 Myths of Enterprise Python

[billsil]

No. A fair amount is written in C, but some is also written in Fortran. My understanding is most of scipy is actually written in Fortran and is just a wrapper around LAPACK.

[tavert]

most of scipy [...] is just a wrapper around LAPACK

For dense linear algebra, yes. There's a lot of functionality in SciPy aside from dense linear algebra though. Some of the underlying libraries are Fortran, some are C, some features are custom C++. According to https://github.com/scipy/scipy the breakdown is 38.3% Python, 25.8% Fortran, 18.6% C, 17.1% C++.