@sh.add_function(dsp, outputs=['planetary_ratio'])
def identify_planetary_ratio(
planetary_speeds_in, engine_speeds_out, final_drive_speeds_in):
"""
Calculates final drive speed [RPM].
:param planetary_speeds_in:
Planetary speed vector [RPM].
:type planetary_speeds_in: numpy.array
:param engine_speeds_out:
Engine speed vector [RPM].
:type engine_speeds_out: numpy.array
:param final_drive_speeds_in:
Final drive speed in [RPM].
:type final_drive_speeds_in: float
:return:
Fundamental planetary speed ratio [-].
:rtype: numpy.array
"""
r = planetary_speeds_in - engine_speeds_out
r /= engine_speeds_out - final_drive_speeds_in
return co2_utl.reject_outliers(r)