Is it possible to integrate Cython and TG2? I have one computation (written in python) which is heavily numerical and would largly benefit from rewriting into C or cython.
Without you having additionally specificity in your question and not knowing what exactly you mean by 'integrate', all I can offer is that cython provides a fairly simple way of (often dramatically) speeding up certain code written in python either via static typing or calling external c/c++ libraries. If there is only a single numerical calculation that can be written in cython and then called from within TG2, then this is a good candidate for using cython. Your mileage will vary though depending on how much of it can be written in something that translates to pure C, versus something that relies heavily on the Python C-API.
Some (many actually) numerical calculations are also amenable to the type computations that numpy excels at, so if you haven't tried it, that may be another option.
In general though if you want a detailed answer, you should put an equivalent amount of detail in the question.