Function stated_angle_difference_bounds 

pub fn stated_angle_difference_bounds(
    angle_min: f64,
    angle_max: f64,
) -> (f64, f64)

One branch angle difference interval as the source states it, for a consumer that applies no pad. Inputs and outputs are radians.

The interval constrains theta_from - theta_to, as MATPOWER and PowerModels define it. The MATPOWER 0/0 spelling states no constraint. A lower side at or below −360 degrees and an upper side at or above 360 degrees also denote absent limits. Absent sides become negative or positive infinity, respectively: unwrapped DC angle differences can exceed a full turn. Every other stated bound passes through unchanged.