Thanks @ptrblck. The estimator I have developed is a classifier. You can see it here if you’re interested: https://github.com/leockl/helstrom-quantum-centroid-classifier 15
Based on what you said about a large number of numpy operations are implemented in PyTorch, I don’t think I will have issues with the code as it is mostly all written using numpy arrays.
However, I am still not very clear on how to inherit from scikit-learn’s BaseEstimator and ClassifierMixin (which allows for methods like .fit(), .predit() etc.) into PyTorch. Any clues, directions or even better examples on this would really be appreciated. Many thanks in advance.