SAFD-algorithm VS array

Hello everybody, I want to share with you a small app / program I developed some time ago (and which I am maintaining) which can be used to compute the coefficients of a function development in a spherical harmonics convergent series . Spherical harmonics are a set of functions used to find a solution of the Schroedinger equation for the hydrogen atom for example, in quantum physics. The coefficients computed to find a function development (which function depends on polar and azimuthal angle in spherical coordinates) are used in many field of physics. I decided for fun to develope a program to compute them. Tell me what do you think and of course any hint is more than welcome! You are free to send a pull request or open issues if you want, I'll feature you in the main README file, directly in the contributor list. If you like the repo, don't forget to leave a star! Thanks. Repository link: https://github.com/JustWhit3/SAFD-algorithm

GitHub repository: https://github.com/JustWhit3/SAFD-algorithm

On the part of templates VS aliases: I disagree, that long names would "spoil" the code. Readability & Maintenance > Esthetic ! As I first read your code, I was confused about these custom types and later on, I saw that they were just default types named different. Maybe this works good for you, but I guess this does not hold for the major C++ developers. For example, look how Boost::array is doing this: