Struct NdiParams 

pub struct NdiParams {
    pub tau: f64,
    pub alpha: f64,
    pub max_iter: usize,
    pub auto_stop: bool,
    pub b0: f64,
    pub echo_times: Vec<f64>,
    pub te: EchoTime,
    pub kernel: FansiKernel,
}

NDI algorithm parameters

Fields

tau: f64

Gradient-descent step size

alpha: f64

L2 regularization weight

max_iter: usize

Number of iterations (the maximum, with auto_stop)

auto_stop: bool

Stop once the high-frequency energy of the estimate along the dipole cone exceeds that just off it (FANSI ndi_auto.m)

b0: f64

Field strength in Tesla (scan parameter, for the radian conversion)

echo_times: Vec<f64>

Echo times in seconds, in acquisition order (scan parameter, for the radian conversion).

te: EchoTime

Which echo time the radian conversion uses. Default EchoTime::First. FANSI’s multi-echo example, script_DICOM_Philips.m, scales the field by deltaTE = TE(echo2) - TE(echo1) (FANSI-toolbox 93044a3, line 364) before ndi (lines 459, 465), and its comment on that line says “You may use also any individual echo time”. On the qsm-forward phantom (echoes 4/12/20/28 ms; FANSI’s discrete kernel, measured for QSM.rs#418 with the integration tests’ settings; XSIM / NRMSE / r), the magnitude weight at the first echo gives the best NRMSE and r (0.635 / 52.0% / 0.854) against 0.636 / 54.0% / 0.842 at the echo spacing. (With the continuous kernel, #276: 0.636 / 51.4% / 0.858 against 0.637 / 53.3% / 0.846.)

The magnitude weight is required, although ndi.m weights by ones when given none (lines 51-56): with a flat weight NDI is worse on that phantom (0.625 / 58.8% / 0.818 at the first echo, 0.630 / 57.3% / 0.825 at the spacing; continuous kernel 0.628 / 57.5% / 0.822 at the first echo).

kernel: FansiKernel

The dipole kernel. Default FansiKernel::Discrete, FANSI’s dipole_kernel_angulated as the original is run with; FansiKernel::Continuous is the crate’s continuous kernel (see FansiKernel for the decision and the measurements).

Implementations

impl NdiParams

pub fn auto() -> Self

FANSI ndi_auto.m defaults: automatic stopping, at most 500 iterations.

Trait Implementations

impl Clone for NdiParams

fn clone(&self) -> NdiParams

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for NdiParams

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

Formats the value using the given formatter.

impl Default for NdiParams

fn default() -> Self

FANSI ndi.m defaults.

impl Serialize for NdiParams

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

where __S: Serializer,

Serialize this value into the given Serde serializer.