def phi_from_spinx_spiny(spinx, spiny):
    """Returns the angle between the x-component axis and the in-plane spin.
    """
    phi = numpy.arctan2(spiny, spinx)
    return phi % (2 * numpy.pi)
def phi_from_spinx_spiny ( spinx , spiny ) : phi = numpy . arctan2 ( spiny , spinx ) return phi % ( 2 * numpy . pi )
Returns the angle between the x-component axis and the in-plane spin.