Function add_error_pointwise 

pub fn add_error_pointwise(
    data: &[f64],
    _nrow: usize,
    _ncol: usize,
    sd: f64,
    seed: Option<u64>,
) -> Vec<f64>

Add pointwise Gaussian noise to functional data.

Adds independent N(0, σ²) noise to each point.

Arguments

• data - Data matrix (n × m) in column-major format
• nrow - Number of rows (observations)
• ncol - Number of columns (evaluation points)
• sd - Standard deviation of noise
• seed - Optional random seed

Returns

Noisy data matrix (n × m) in column-major format