Function std_deviation

performance-metrics/src/main.rs:341–359

(data: &[f64])

}

fn std_deviation(data: &[f64]) -> Option<f64> {
    let count = data.len();

    if count > 0 {
        let mean = mean(data).unwrap();
        let variance = data
            .iter()
            .map(|value| {
                let diff = mean - *value;
                diff * diff
            })
            .sum::<f64>()
            / count as f64;

        Some(variance.sqrt())
    } else {
        None
    }
}

mod adjuster {
    pub fn identity(v: f64) -> f64 {