Struct ProbitFrailtyScaleJet 

pub struct ProbitFrailtyScaleJet {
    pub s: f64,
    pub alpha: f64,
    pub ds: f64,
    pub d2s: f64,
}

Probit frailty scaling factor with t-derivatives (t = log σ).

Provides exact closed-form derivatives of s = 1/√(1+σ²) with respect to t = log(σ) for learnable Gaussian-shift frailty in the marginal-slope families. For Gaussian frailty on the final probit index E[Φ(η + U)] = Φ(η · s) with s = 1/√(1+σ²); writing α = σ²/(1+σ²) the derivatives are ∂t s = −α·s and ∂{tt} s = α(3α−2)·s.

Fields

s: f64

s = 1/√(1+σ²)

alpha: f64

α = σ²/(1+σ²) — shared auxiliary for all derivative levels.

ds: f64

∂_t s = -α·s

d2s: f64

∂_{tt} s = α(3α−2)·s

Implementations

impl ProbitFrailtyScaleJet

pub fn new(sigma: f64) -> Self

Build the jet from σ (not from t = log σ).

At σ = 0 the jet degenerates to (s=1, α=0, ds=0, d2s=0), which is correct: zero frailty means s ≡ 1 independent of t.

pub fn from_log_sigma(log_sigma: f64) -> Self

Build the jet from t = log(σ) directly.

Trait Implementations

impl Clone for ProbitFrailtyScaleJet

fn clone(&self) -> ProbitFrailtyScaleJet

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for ProbitFrailtyScaleJet

impl Debug for ProbitFrailtyScaleJet

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

Formats the value using the given formatter.