I'm debating whether to use C++ or Python for a largely math-based program. 
Both have great math libraries, but which language is generally faster for complex math?
You could also consider a hybrid approach. Python is generally easier and faster to develop in, specially for things like user interface, input/output etc. 
C++ should certainly be faster for some math operations (although if your problem can be formulated in terms of vector operations or linear algebra than numpy provides a python interface to very efficient vector manipulations).
Python is easy to extend with Cython, Swig, Boost Python etc. so one strategy is write all the bookkeeping type parts of the program in Python and just do the computational code in C++.
C++ or Python for an Extensive Math Program?