rxUiGet.foceiHdEta2: Second-order eta sensitivities of the prediction for the...

In nlmixr2est: Nonlinear Mixed Effects Models in Population PK/PD, Estimation Routines

Second-order eta sensitivities of the prediction for the exact log-likelihood ('ll()'/generalized) inner Hessian under 'fast=TRUE'.

Description

For a generalized endpoint 'rx_pred_' is the per-observation log-density, so its second eta-derivatives 'd2(rx_pred_)/deta_i deta_j' let 'calcEtaHessian' assemble the exact inner Hessian 'H = Omega^-1 - sum_obs d2(logLik)/deta2' analytically – mirroring the Gaussian Gauss-Newton 'sum(cHff*a*a)+Omega^-1' assembly – instead of the Shi21 finite difference of the inner gradient. Reuses the augmented-model second-order chain ('.g2', see [.foceiAnalyticAugModelDirs]). Stores on the symengine env '..HdEta2' (the 'rx__d2pred_i_j__' lhs lines, upper triangle i<=j) and '..sens2' (the second-order state-sensitivity ODEs). Only built for a fast generalized fit; the ordinary inner model is unchanged.

Usage

## S3 method for class 'foceiHdEta2'
rxUiGet(x, ...)

Arguments

x	list of rxode2 UI
...	ignored

Value

symengine env with '..HdEta2' and '..sens2' added

nlmixr2est documentation built on Aug. 5, 2026, 1:11 a.m.