Function csch_rrule 

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

Reverse rule for csch.

Examples

use chainrules::csch_rrule;

let dy = csch_rrule(0.5_f64, 1.0);
let csch_x = 1.0 / 0.5_f64.sinh();
assert!((dy + csch_x * 0.5_f64.cosh() / 0.5_f64.sinh()).abs() < 1e-12);