Struct GridND 

pub struct GridND<F: SemiflowFloat = f64, const D: usize = 2> {
    pub axes: [Grid1D<F>; D],
    pub interp: InterpKind,
}

d-dimensional tensor-product grid with uniform axes.

Each axis is a Grid1D<F> with independent geometry, boundary policy, and interpolation kind. Dimension D is a const generic parameter. Values are stored axis-0-fastest: flat_idx = k_{D-1}·n_{D-2}·…·n₀ + … + k₁·n₀ + k₀.

Example

use semiflow::{Grid1D, grid_nd::GridND};
let axes = core::array::from_fn(|_| Grid1D::new(-5.0_f64, 5.0, 16).unwrap());
let grid = GridND::<f64, 2>::new(axes).unwrap();
assert_eq!(grid.len(), 256); // 16*16

Fields

axes: [Grid1D<F>; D]

Per-axis grids. axes[0] is the fastest-varying axis.

Each axis contributes its own crate::grid::BoundaryPolicy to GridFnND::sample. The axes’ individual InterpKinds are NOT consulted — see GridND::interp.

interp: InterpKind

Tensor-product interpolation kind used by GridFnND::sample.

Default InterpKind::CubicHermite (ADR-0191). A single grid-level knob rather than a per-axis one because Grid1D::new already stamps every axis with SepticHermite, leaving no way to tell a deliberate choice from an inherited default. CubicHermite removes the accumulated per-step interpolation variance at 4^D nodes per sample; SepticHermite would cost 8^D for no gain on that failure mode, and is not implemented for D > 1.

Implementations

impl<F: SemiflowFloat, const D: usize> GridND<F, D>

pub fn new(axes: [Grid1D<F>; D]) -> Result<Self, SemiflowError>

Construct from an array of D axes.

Errors

• DomainViolation if D == 0.
• DomainViolation if any axis has n < 4.

pub fn with_interp(self, interp: InterpKind) -> Self

Override the tensor-product interpolation kind (builder, ADR-0191).

Only InterpKind::CubicHermite and InterpKind::Linear are implemented for D > 1; the others make GridFnND::sample return SemiflowError::Unsupported. Linear needs the linear-interp feature, matching the 1-D contract.

pub fn len(&self) -> usize

Total number of grid points: n₀ · n₁ · … · n_{D-1}.

pub fn is_empty(&self) -> bool

Returns false for any valid GridND (all axes have n >= 4).

pub fn n_along(&self, d: usize) -> usize

Number of nodes along axis d.

Panics

Panics if d >= D (debug only).

pub fn flat_idx(&self, idx: &[usize; D]) -> usize

Convert a multi-index [k₀, k₁, …, k_{D-1}] to a flat index.

Axis 0 is fastest-varying (row-major in axis-0 direction).

Panics

Panics in debug if kd >= n_d for any d.

pub fn x_at(&self, d: usize, k: usize) -> F

Physical coordinate of multi-index [k₀, …, k_{D-1}] on axis d.

pub fn centre(&self) -> [F; D]

Physical coordinates of the grid CENTRE (used for SPD validation).

Trait Implementations

impl<F: Clone + SemiflowFloat, const D: usize> Clone for GridND<F, D>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.