Function add_rrule 

pub fn add_rrule<S: ScalarAd>(cotangent: S) -> (S, S)

Reverse rule for add.

Returns cotangents with respect to (x, y).

Examples

use chainrules::add_rrule;

let (dx, dy) = add_rrule(1.25_f64);
assert_eq!(dx, 1.25_f64);
assert_eq!(dy, 1.25_f64);