Function cbrt_rrule 

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

Reverse rule for cbrt.

Examples

use chainrules::cbrt_rrule;

let dx = cbrt_rrule(2.0_f64, 1.0);
assert!((dx - (1.0 / 12.0)).abs() < 1e-12);