Possible for beam x/y pols to incorrectly be compared to uvdata directional pols.

[aewallwi]

The function _get_req_pols currently assumes that the feed values for a uvbeam object with non None x_orientation are set to N or E. However, there are valid uvbeam objects where feed_array contains 'x' or 'y' with x_orientation specifying the mapping from the xy labels to the directions. As written, this function will incorrectly conclude that the nn, ee, neanden` pols are not present in the uvbeam object (when converted to power).

hera_sim/hera_sim/visibilities/vis_cpu.py

Line 414 in 4c0c324

def _get_req_pols(self, uvdata, uvbeam, polarized: bool) -> List[Tuple[int, int]]:

[piyanatk]

@aewallwi Yes, I think you are correct that if x_orientation is None, they are assume to be N and E, but I might be wrong. We had lengthy discussion on how to implement this. I will leave it to @steven-murray or @r-pascua for details.

Can you provide example print out of feed_array and x_orientation of a UVBeam where the latter contain mapping? I think we should support that but it is a separate issue on default assumption of x_orientation (which I think we already have sensible a set up.)