Module sigma_link

Structs§

EXP_NEG_STABLE_MAX_ARG: Maximum exponent argument for the one-sided overflow guard on the inverse sigma link. exp(500) ≈ 1.4e217 leaves ~91 orders of magnitude of headroom before reaching f64::MAX ≈ 1.8e308, sufficient for any reasonable downstream multiplicative chain.
LOGB_SIGMA_FLOOR: Lower bound on σ in response-scaled units for the location-scale GAMLSS noise link σ = LOGB_SIGMA_FLOOR + exp(η). Mirrors mgcv’s gaulss(b=0.01) default. The Gaussian location-scale log-likelihood

exp_neg_stable: Overflow-safe exp(-x): guards against overflow when x is very negative (so exp(-x) would overflow to +inf) by capping the exponent at +500, but allows natural IEEE 754 underflow to 0.0 when x is very positive.
exp_sigma_derivs_up_to_fourth
exp_sigma_derivs_up_to_fourth_scalar
exp_sigma_derivs_up_to_third
exp_sigma_derivs_up_to_third_scalar
exp_sigma_eta_for_sigma_scalar
exp_sigma_from_eta_scalar
exp_sigma_inverse_from_eta_scalar: Inverse exp-link 1/σ = exp(-η) with the one-sided overflow guard from exp_neg_stable. Required by every solver path that forms products like t · exp(-η_ls) — without the guard, very negative η_ls produces +inf, which propagates as NaN through subsequent multiplications and breaks the monotonicity floor / penalty chain.
exp_sigma_jet1_scalar
exp_sigma_jet3_scalar
logb_sigma_derivs_up_to_fourth
logb_sigma_derivs_up_to_fourth_scalar
logb_sigma_derivs_up_to_third_scalar
logb_sigma_eta_for_sigma_scalar
logb_sigma_from_eta_scalar
logb_sigma_from_eta_with_floor_scalar: Reconstruct σ from η with an explicit, response-scale-relative floor.
logb_sigma_jet1_scalar
logb_sigma_jet3_scalar
safe_exp: Exact exponential link on the native f64 range.