Function box_cox 

pub fn box_cox(y: &[f64], lambda: f64) -> Result<Vec<f64>, TransformError>

Apply the Box-Cox power transformation to positive data.

For each element yᵢ > 0:

y(λ) = ln(y)           when |λ| < 1e-10
        (y^λ - 1) / λ   otherwise

Errors

• TransformError::InsufficientData — fewer than 2 data points
• TransformError::NonPositiveData — any element ≤ 0

Examples

use u_numflow::transforms::box_cox;

let y = vec![1.0, std::f64::consts::E];
let y_t = box_cox(&y, 0.0).unwrap();
assert!((y_t[0] - 0.0).abs() < 1e-10);
assert!((y_t[1] - 1.0).abs() < 1e-9);