Question about zero123 azimuth angle

[ug-kim]

Hello, I have some questions about the azimuth angle of zero123.

95f72bb#diff-90e65461624aace29412e4625384cd3a3e3f96731f13b29686bfcc6c34b871b6

In this commit, you change your code like below.

However, in the zeor123 paper in supplementary, azimuth is encoded with phi -> [sin(phi), cos(phi)].
(theta is polar, phi is azimuth).

What is the difference between these two encodings of azimuth, and why you changed like that?
(two encodings are 1) phi -> [sin(phi), cos(phi)], 2) phi -> [sin(-phi), cos(phi)])