Similar to this and this I'm trying to recover the original 2D field after the arctan2 operation.
Here's a MWE in python:
import numpy as np
theta = np.random.uniform(low=-3*np.pi, high=3*np.pi, size=400)
theta = theta.reshape(20,20)
y = np.sin(theta)
x = np.cos(theta)
phi = np.arctan2(y, x)
# theta = f(phi)?how to find f? Thanks.
