Function r2star_qsm_from_magnitude 

pub fn r2star_qsm_from_magnitude(
    magnitude: &[f64],
    echo_times: &[f64],
    chi_total: &[f64],
    mask: &[u8],
    params: &R2starQsmParams,
) -> (Vec<f64>, Vec<f64>, Vec<f64>)

R2*-QSM separation fitting R2* from multi-echo magnitude, then separating.

Fits R2* by magnitude-weighted log-linear least squares (weight ∝ magnitude²), matching the QSM-CI reference implementation, then calls r2star_qsm.

Arguments

• magnitude — Multi-echo magnitude, flattened as (n_voxels, n_echoes) in row-major order (echo fastest per voxel) — the same layout as crate::r2star::r2star_arlo.
• echo_times — Echo times in seconds (n_echoes).
• chi_total — Conventional QSM χ_total in ppm (n_voxels).
• mask — Binary brain mask (n_voxels).
• params — See R2starQsmParams.

Returns

(chi_pos, chi_neg, chi_total) as in r2star_qsm.