qspec.orthonormal_rtp  (  r ,  axis = -1  )[source]

Parameters:

rarray_like

The first vector of the orthonormal system. Does not have to be normalized.

axisNone

The axis along which the vector components are aligned.

Returns:

out(array_like, array_like, array_like)

The three orthonormal vectors 'e_r', 'e_theta' and 'e_phi' given the vector 'r' pointing in the 'e_r' direction.