Struct SphericalSplineBasisSpec 

pub struct SphericalSplineBasisSpec {
    pub center_strategy: CenterStrategy,
    pub penalty_order: usize,
    pub double_penalty: bool,
    pub radians: bool,
    pub method: SphereMethod,
    pub max_degree: Option<usize>,
    pub wahba_kernel: SphereWahbaKernel,
    pub identifiability: SphericalSplineIdentifiability,
}

Intrinsic S² (sphere) smooth configuration.

Fields

center_strategy: CenterStrategy

Center/knot selection strategy in latitude/longitude coordinates (used only when method == Wahba).

penalty_order: usize

Sphere roughness penalty order m ∈ {1, 2, 3, 4}.

• Wahba method, Sobolev kernel (default): the reproducing-kernel norm is Σ_l [l(l+1)]^m · |f̂_l|² — the canonical H^m(S²) Sobolev norm. m=2 is the usual curvature (thin-plate analogue) penalty.
• Wahba method, Pseudo kernel: the order maps to the Wahba 1981 pseudo-spline kernel with Legendre weights 2 / [(l+1)(l+2)···(l+m+1)]. Same m=2 is the TPS pseudo-spline.
• Harmonic method: raises the Laplace-Beltrami eigenvalue penalty to [l(l+1)]^m (same as the Sobolev kernel norm above).

double_penalty: bool

Add a ridge-like shrinkage penalty.

radians: bool

Interpret latitude/longitude in radians instead of degrees. Default is degrees (Earth/data-frame convention); set true for radians.

method: SphereMethod

Construction method. Default Wahba (reproducing kernel); Harmonic uses real spherical harmonics with a Laplace-Beltrami eigenvalue penalty (Wood §5.6.2, mgcv bs="sos").

max_degree: Option<usize>

Maximum spherical-harmonic degree L when method == Harmonic. Basis dimension is L * (L + 2). Ignored for Wahba.

wahba_kernel: SphereWahbaKernel

When method == Wahba, which reproducing kernel to use: Sobolev (true H^m(S²), the default) or Pseudo (Wahba 1981 / mgcv bs="sos"). See SphereWahbaKernel docs.

Deserialised specs that omit this field fall back to the standard Default (Sobolev). Saved models that pre-date this field are not supported — they must be re-fit with the current encoding.

identifiability: SphericalSplineIdentifiability

Realized-design identifiability policy for the Wahba sphere (#532).

The finite-center Wahba kernel design K(data, centers) · z can span a near-constant direction on the data rows even though the continuous kernel omits the l=0 mode. In any model with a parametric intercept this collides with the global intercept — the #531 constant-vs-intercept rank-1 collision class. The fix (mirroring MaternIdentifiability::FrozenTransform) lets the global identifiability pipeline compose a parametric-orthogonalization onto z and freeze the composed transform here, so the predict-time rebuild reuses the exact fit-time realized transform instead of silently dropping the orthogonalization.

Trait Implementations

impl Clone for SphericalSplineBasisSpec

fn clone(&self) -> SphericalSplineBasisSpec

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SphericalSplineBasisSpec

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

Formats the value using the given formatter.

impl Default for SphericalSplineBasisSpec

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for SphericalSplineBasisSpec

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for SphericalSplineBasisSpec

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

where __S: Serializer,

Serialize this value into the given Serde serializer.