How to write a user-defined model
I want to learn how to write a user-defined model in PSSE but I do not know where to start. First, I started to learn Fortran language since the model should be written in Fortran. But I would appreciate if anyone can guide me with the correct steps to follow and propose organized resources to learn from.
Also if anyone has a simple example of a user-defined model such that I can start by redoing it.