Function l2_distance 

pub fn l2_distance(a: &[f32], b: &[f32]) -> f32

L2 (Euclidean) distance: sqrt(Σ(a[i] - b[i])²).

Example

use innr::l2_distance;

let a = [0.0_f32, 0.0];
let b = [3.0_f32, 4.0];
assert!((l2_distance(&a, &b) - 5.0).abs() < 1e-6);