Function equal_width_bin 

pub fn equal_width_bin(
    col: &[f64],
    n_bins: usize,
    out: &mut [f64],
) -> Result<(), DataError>

Equal-width binning of a float column into n_bins integer codes in 0..n_bins.

Non-finite values are rejected (no silent map to bin 0).

Errors

Empty n_bins, length mismatch, or non-finite input.