Function functional_std 

pub fn functional_std(data: &FdMatrix) -> Result<Vec<f64>, FdarError>

Compute pointwise sample standard deviation of functional data (ddof = n-1).

Delegates to functional_variance so that functional_std(data)[j]^2 == functional_variance(data)[j] holds by construction.

Arguments

• data - Functional data matrix (n x m), requires n >= 2.

Returns

Length-m vector of pointwise sample standard deviations.

Errors

Returns FdarError::InvalidDimension if n < 2.

Examples

use fdars_core::matrix::FdMatrix;
use fdars_core::fdata::{functional_std, functional_variance};

let data = FdMatrix::from_column_major(vec![1.0, 3.0, 4.0, 2.0], 2, 2).unwrap();
let std = functional_std(&data).unwrap();
let var = functional_variance(&data).unwrap();
// std^2 == var pointwise
for j in 0..2 {
    assert!((std[j].powi(2) - var[j]).abs() < 1e-10);
}