Function parametric_decay 

pub fn parametric_decay(x: f32, params: &DecayParams) -> f32

Weibull survival function: S(x; τ, β) = exp(-ln(2) · (x/τ)^β)

Returns a value in [0.0, 1.0] representing the decay of a signal at distance/time x from origin.

Panics

Debug-asserts that params.half_life > 0 and params.shape > 0. In release builds, invalid params produce NaN or 0.0.

Properties

All properties below are verified by the property test suite:

• P1: parametric_decay(0, _) == 1.0
• P2: parametric_decay(τ, {τ, 1.0}) ≈ 0.5
• P3: Monotone decreasing in x
• P4: Output ∈ [0.0, 1.0]
• P5: Approaches 0 as x → ∞