Struct IlsqrParams 

pub struct IlsqrParams {
    pub tol: f64,
    pub max_iter: usize,
    pub pad_mm: f64,
    pub precision: IlsqrPrecision,
}

Parameters for the iLSQR algorithm.

The iteration cap defaults to QSM_iLSQR’s own default, 100, which is what runs when it is called as a function without 'niter': UK Biobank’s pipeline and STI Suite’s own STI_Templates.m example call it that way (decided 2026-10-29; until then the default was the GUI’s 40, which remains available as max_iter: STI_GUI_NITER). The padding defaults to what STI Suite 3.0’s QSM_GUI passes (as for STAR-QSM’s padding, crate::inversion::StarParams::pad). Probed in MATLAB R2023b by driving QSM_GUI headless (“3D GRE data”, then “iLSQR”) with a logging wrapper around QSM_iLSQR: the GUI passes a params struct with niter 40, padsize [12 12 12], tol_step1 0.01, tol_step2 0.001 and Kthreshold 0.1, bitwise equal to QSM_iLSQR(..., 'padsize', [12 12 12], 'niter', 40). Called without them, QSM_iLSQR uses niter 100 and padsize 6. The initial LSQR solve always uses STI’s tolerance of 0.01. max_iter is STI’s 'niter' argument (it caps both solves). pad_mm is STI’s 'padsize' (see the module docs, Padding).

Measured, the GUI’s settings (40, 12 mm) against the function’s defaults (100, 6 mm): on the qsm-forward phantom’s true local field χ XSIM 0.686 → 0.671, NRMSE 40.3 → 42.0 %, r 0.916 → 0.908 (the fewer iterations; 12 mm alone changes little), at under half the run time; behind the pipeline’s V-SHARP the differences are ≤ 0.01 XSIM (phantom 0.308 → 0.301). On an in-vivo 3T scan behind the default V-SHARP, agreement with the UK Biobank pipeline’s χ is XSIM 0.772 → 0.764, NRMSE 75.5 → 73.5 %, r 0.814 → 0.820.

Fields

tol: f64

Tolerance of the streaking-artefact solve (default: 1e-3)

max_iter: usize

Maximum iterations of each LSQR solve: STI’s 'niter' (default STI_DEFAULT_NITER = 100, QSM_iLSQR’s own default, which UK Biobank, STI_Templates.m and the χ-separation toolbox’s Chisep_script.m leave in place; QSM_GUI passes STI_GUI_NITER = 40, and QSMART 50)

pad_mm: f64

Zero padding per side in mm, on every axis: STI’s 'padsize' (default STI_GUI_PAD_MM = 12, what QSM_GUI passes; STI_DEFAULT_PAD_MM = 6 is QSM_iLSQR’s own default and STI_PAD_MM reproduces UK Biobank / STI Suite’s examples). Must be finite and ≥ 0.

precision: IlsqrPrecision

Arithmetic of the two LSQR solves (default IlsqrPrecision::Double; Single is STI Suite’s own, for parity with it)

Implementations

impl IlsqrParams

pub fn validate(&self) -> Result<(), String>

Checks the parameters: pad_mm must be finite and ≥ 0.

Trait Implementations

impl Clone for IlsqrParams

fn clone(&self) -> IlsqrParams

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for IlsqrParams

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for IlsqrParams

fn default() -> Self

Returns the “default value” for a type.

impl Serialize for IlsqrParams

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.