convert arctan2 result from -1*pi .. +1*pi to 0 .. 2*pi

arctan2_2pi.py

# The arctan2 funtion returns an angle between -PI and +PI (radians)
# If you need a range from zero to 2PI, this is how the
# arctan2 result can be converted.
# Zero still means "aligned with the 'x' axis"
# And the angle is still to be interpreted counter-clockwise.

import numpy as np

def arctan2_2pi(y, x):
    return -1 * (
            np.arctan2(
            y, (-1) * x
        ) - np.pi
    )
    
assert arctan2_2pi(0, 1) == 0
assert arctan2_2pi(1, 1) == np.pi/4
assert arctan2_2pi(1, 0) == np.pi/2
assert arctan2_2pi(1, -1) == 3*np.pi/4
assert arctan2_2pi(0, -1) == np.pi
assert arctan2_2pi(-1, -1) == 5 * np.pi/4
assert arctan2_2pi(-1, 0) == 3 * np.pi/2
assert arctan2_2pi(-1, 1) == 7 * np.pi/4