SpectralRadex is a python module made up of two parts: a RADEX wrapper and a spectral model.
A number of libraries exist for the first purpose. However, SpectralRadex uses F2PY to compile a version of RADEX written in modern Fortran. As a result, running a RADEX model creates no subprocesses, no text files, and can be easily parallelized. Check our tutorials section for an example of running a grid of RADEX models quickly and entirely within Python.
For the second purpose, we use the RADEX calculated line opacities and excitation temperatures to calculate the brightness temperature as a function of frequency. This allows observed spectra to be modelled in python in a non-LTE fashion. See our spectral modelling tutorial for more.