Function normal_strain 

pub fn normal_strain(change_in_length: f64, original_length: f64) -> Option<f64>

Computes normal strain from change in length and original length.

Formula: ε = ΔL / L0.

Returns None when original_length is less than or equal to zero or when any input or result is not finite.

Examples

use use_elasticity::normal_strain;

assert_eq!(normal_strain(2.0, 10.0), Some(0.2));