PRIMO is a way to fit models to the data in image-space. Since the models are very expensive to run it's not feasible to sample the model parameters directly in order to find a fit to data. Instead they take a library of model outputs and parameters and do a principle component analysis in image-space. This allows them to very cheaply generate new samples without running the complete simulation for each new set of parameters.

Principle component analysis is an old school analytical numerical method and has nothing to do with AI.