Function ilsqr 

pub fn ilsqr(
    field: &[f64],
    mask: &[u8],
    nx: usize,
    ny: usize,
    nz: usize,
    vsx: f64,
    vsy: f64,
    vsz: f64,
    bdir: (f64, f64, f64),
    tol: f64,
    maxit: usize,
) -> (Vec<f64>, Vec<f64>, Vec<f64>, Vec<f64>)

iLSQR: A method for estimating and removing streaking artifacts in QSM

Arguments

• field - Unwrapped local field/tissue phase (nx * ny * nz)
• mask - Binary mask of region of interest
• nx, ny, nz - Array dimensions
• vsx, vsy, vsz - Voxel sizes in mm
• bdir - B0 field direction (bx, by, bz)
• tol - Stopping tolerance for LSMR solver
• maxit - Maximum iterations for LSMR

Returns

Tuple of (susceptibility, streaking_artifacts, fast_qsm, initial_lsqr)