Function sec_frule 

pub fn sec_frule<S: ScalarAd>(x: S, dx: S) -> (S, S)

Forward rule for sec.

Examples

use chainrules::sec_frule;
let (y, dy) = sec_frule(0.5_f64, 1.0);
assert!((y - 1.0 / 0.5_f64.cos()).abs() < 1e-12);
assert!((dy - (0.5_f64.sin() / 0.5_f64.cos().powi(2))).abs() < 1e-12);