RotatingFrame.vectorized_map_into_frame is not JAX compatible and has ambiguous name

[DanPuzzuoli]

The problem

This method is not JAX compatible (simple fix).

It is also "ambiguous" in the sense that "vectorized_map" does not indicate the nature of the transformation - a vectorized map in this context could either be the state of a differential equation or an operator that acts on states, and both are subject to different transformation rules. It currently implements the operator transformation, and there is no way to do a vectorized state transformation.

Suggestion

JAX fix is easy - I think there is a single usage of np that can be changed to unp. Along with this though, tests need to be added that would have caught this. I don't believe this method is being tested anywhere.

For the ambiguity, this method should be renamed vectorized_map -> vectorized_operator, and the equivalent vectorized_state method should also be added. There also isn't an out_of_frame version of this function, so one should be added for each of the operator and state methods.

[DanPuzzuoli]

One thing to note here is that the "vectorized" transformations can be implemented by the standard RotatingFrame methods but with the frame operator being the vectorized version of the map X -> [F, X]. So, an elegant solution to implementing these methods may be to just internally construct a RotatingFrame instance using the vectorized frame, and then call the ordinary methods.