Function exp2_rrule 

pub fn exp2_rrule<S: ScalarAd>(result: S, cotangent: S) -> S

Reverse rule for 2^x.

Examples

use chainrules::exp2_rrule;

let dy = exp2_rrule(8.0_f64, 1.0);
assert!((dy - 8.0_f64 * std::f64::consts::LN_2).abs() < 1e-12);