code: def grid_to_grid_cartesian(self, grid, radius):
          
          grid_thetas = np.arctan2(grid[:, 0], grid[:, 1])
          cos_theta, sin_theta = self.grid_angle_to_profile(grid_thetas=grid_thetas)
          return np.multiply(radius[:, None], np.vstack((sin_theta, cos_theta)).T)
docs: Convert a grid of (y,x) coordinates with their specified circular radii to their original (y,x) Cartesian 
          coordinates.
  
          Parameters
          ----------
          grid : TransformedGrid(ndarray)
              The (y, x) coordinates in the reference frame of the profile.
          radius : ndarray
              The circular radius of each coordinate from the profile center.