Different change of basis matrix when restricting irreps about escnn HOT 1 CLOSED

hi @hlzl

The reason is that id[0] is an integer representing a discrete rotation for the dihedral group while it is an angle in [0, 2pi) for the O(2) group.
However, the function utils.psi expects an angle in [0, 2pi), so the integer must be converted into a rotation angle in the first case. You can see the meaning of the id tuple in the Dihedral group and the O2 group documentations under "Subgroup Structure".

However, you just made me realise that the documentation of the O2._restrict_irrep() method is incorrect, although it should not be rendered in the docs pages.

Anyways, I will fix it, thanks!

Gabriele

from escnn.