Struct Grid 

pub struct Grid {
    pub dims: (usize, usize, usize),
    pub voxel_size: (f64, f64, f64),
}

A 3D volume grid with dimensions and voxel sizes.

Fields

dims: (usize, usize, usize)

Volume dimensions (nx, ny, nz)

voxel_size: (f64, f64, f64)

Voxel sizes in mm (vsx, vsy, vsz)

Implementations

impl Grid

pub fn new( nx: usize, ny: usize, nz: usize, vsx: f64, vsy: f64, vsz: f64, ) -> Self

Create a new Grid from dimensions and voxel sizes.

pub fn nx(&self) -> usize

pub fn ny(&self) -> usize

pub fn nz(&self) -> usize

pub fn vsx(&self) -> f64

pub fn vsy(&self) -> f64

pub fn vsz(&self) -> f64

pub fn n_total(&self) -> usize

Total number of voxels.

pub fn spacing(&self, axis: usize) -> f64

Spacing along one axis, in mm. axis is 0 = x, 1 = y, 2 = z.

Panics

If axis is not 0, 1 or 2.

pub fn extent(&self, axis: usize) -> usize

Number of samples along one axis. axis is 0 = x, 1 = y, 2 = z.

Panics

If axis is not 0, 1 or 2.

pub fn require_contiguous_slices_if_known( &self, slices: Option<SliceGeometry>, ) -> Result<(), SliceGapError>

Check contiguity against slice geometry the acquisition may not have recorded.

None means the acquisition did not say how thick its slices are, and a gap then cannot be detected — nothing in a NIfTI distinguishes 3 mm slices every 3 mm from 2 mm slices every 3 mm, because the spacing is the pitch. This returns Ok in that case, deliberately and in one place rather than at each call site: refusing every acquisition that failed to record a recommended BIDS field would block the vast majority of data, which has no gap. The missing information is in the input, not in this crate, and the right response is for the host to say so once.

The name says if_known so no call site can read as though a gap had been ruled out. Where the thickness is known, this is Grid::require_contiguous_slices.

pub fn require_contiguous_slices( &self, slice_thickness: f64, slice_axis: usize, ) -> Result<(), SliceGapError>

Check that the volume is contiguous along the slice axis, as the FFT dipole kernel requires.

A 2D multi-slice acquisition often leaves a gap between slices: the excited slab is thinner than the slice-to-slice pitch, so the sampled volume has holes in it. A Grid cannot express that — its voxel_size is the pitch, and nothing records the thickness — so the gap has to be supplied, normally from the acquisition’s SliceThickness sidecar field.

It matters because the dipole kernel, and the spherical kernels of the SHARP family, are evaluated as FFTs on a uniform grid. That is not an approximation that degrades with the gap; the convolution being computed is simply not the one the physics calls for, and the resulting map is wrong rather than noisy — wrong in a way that still looks like a susceptibility map. So this refuses rather than warns.

In-plane work is unaffected: a gap along z does not disturb a purely in-plane kernel, so slice-wise unwrapping is valid on gapped data and deliberately does not call this. Anything that convolves along the slice axis has to.

Arguments

• slice_thickness - Excited slice thickness in mm. For a contiguous acquisition this equals the slice spacing, which is what a 3D acquisition should pass.
• slice_axis - Axis the slices are stacked along: 0 = x, 1 = y, 2 = z.

Panics

If slice_axis is not 0, 1 or 2.

Trait Implementations

impl Clone for Grid

fn clone(&self) -> Grid

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Grid

impl Debug for Grid

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

Formats the value using the given formatter.

impl PartialEq for Grid

fn eq(&self, other: &Grid) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Grid