Enum FrailtySpec 

pub enum FrailtySpec {
    None,
    GaussianShift {
        sigma_fixed: Option<f64>,
    },
    HazardMultiplier {
        sigma_fixed: Option<f64>,
        loading: HazardLoading,
    },
}

Frailty modifier specification at the family level.

Two structurally different exact modifiers exist:

1. GaussianShift: additive Gaussian on the final transformation index. Exact for probit families — the existing sextic microcell kernel survives unchanged (just scale denested cell coefficients by 1/√(1+σ²)).

2. HazardMultiplier: lognormal multiplier on the loaded cumulative hazard. Exact for PH/cloglog families — row likelihoods are finite sums of K_{k,m}(μ, σ) kernel terms.

These are mathematically distinct families. Do not mix them.

Variants

None

No frailty modifier.

GaussianShift

Gaussian shift on the final scalar index: U ~ N(0, σ²) added to η. Exact for probit: E[Φ(η + U)] = Φ(η / √(1+σ²)). The existing sextic microcell kernel is preserved.

Fields

sigma_fixed: Option<f64>

Fixed σ, or None if learnable.

HazardMultiplier

Lognormal hazard multiplier: conditional hazard h(t|U) involves exp(U). Exact for PH/cloglog/survival via K_{k,m} kernel.

Fields

sigma_fixed: Option<f64>

Fixed σ, or None if learnable.

loading: HazardLoading

How the multiplier loads onto hazard components.

Implementations

impl FrailtySpec

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

Validate that this frailty spec is compatible with score_warp/linkwiggle cubic marginal-slope families.

• GaussianShift is exact: the sextic microcell kernel is preserved (probit scaling by 1/τ, τ = √(1+σ²)).
• HazardMultiplier is exact only for PH/cloglog rowwise families. It is NOT finite-state exact with score_warp/linkwiggle cubic marginal-slope, because the multiplicative frailty breaks the polynomial kernel closure that the cubic cell derivatives require.

Returns an error if the combination is not exactly integrable.

Trait Implementations

impl Clone for FrailtySpec

fn clone(&self) -> FrailtySpec

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FrailtySpec

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for FrailtySpec

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for FrailtySpec

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for FrailtySpec

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for FrailtySpec