mceta – Monte-Carlo focei?

nlmixr2 4.0 mceta Two of popular algorithms for fitting nonlinear fixed effects models in pharmacometrics are first order conditional estimation (with interaction), sometimes called focei. This is often considered a classical estimation method As time progressed, Monte-Carlo methods started being used, such as stochastic approximation estimation-maximization (saem). This uses Mote-Carlo Methods to try to find the maximum expectation of the nonlinear-mixed effects model. The new feature I am discussing is mceta for focei, which combines the Monte-Carlo sampling with focei.

nlmixr2 verse 4.0+

nlmixr2 4.0 verse As promised, I am discussing some other change that are breaking and makes nlmixr2 a major release. First is a very visible change as you load nlmixr2: library(nlmixr2) ## ── Attaching packages ───────────────────────────────────────────────────────── nlmixr2 4.0.1 ── ## ✔ lotri 1.0.2 ✔ monolix2rx 0.0.6 ## ✔ nlmixr2data 2.0.9 ✔ nlmixr2lib 0.3.0 ## ✔ nlmixr2est 4.1.0 ✔ nlmixr2rpt 0.2.1 ## ✔ nlmixr2extra 3.0.3 ✔ nonmem2rx 0.1.8 ## ✔ nlmixr2plot 3.

By Matthew Fidler in nlmixr2

August 28, 2025

nlmixr2 4.0

nlmixr2 4.0 We at the nlmixr2 team are committed to quality results. This is seen in line with our vision: The vision of nlmixr2 is to develop a R-based open-source nonlinear mixed-effects modeling software package that can compete with commercial pharmacometric tools and is suitable for regulatory submissions. This release furthers the quality by changing linear compartment models the ADVAN solutions to the WNL solutions(both claim to be something that NONMEM is using for the linear solved systems).

By Matthew Fidler in nlmixr2

July 16, 2025

nlmixr2 ecosystem

nlmixr2 ecosystem I have seen a few new pharmacometrics tools integrated in the nlmixr2 ecosystem recently. I thought I would point out the tools I know that integrate in the nlmixr2 ecosystem. Some are maintained by our nlmixr2 team, and many are not. For each category, these are ordered alphabetically. Tools that Enhance nlmixr2’s language nlmixr2lib In addition to a model library, it has tools to change model components (like add Weibull absorption, add transit compartments, change standard elimination to Michaleis-Menton absorption; maintained by Bill Denney and developed by the nlmixr2 team).

By Matthew Fidler in nlmixr2

June 30, 2025

nlmixr2/rxode2 exploring data with rxode2 geoms

rxode2 and ggplot rxode2 (and nlmixr2) uses ggplot internally. This means most things are compatible with ggplot2. One thing that is not quite as widely known that rxode2 has some custom geom functions that are useful for exploring pharmacometrics data. geom_amt() – exploring when dosing occurs rxode2 will allow exploring time of dosing with the geom_amt(). From the geom_amt() documentation we can see how this is applied: library(rxode2) library(units) ## udunits database from /usr/share/xml/udunits/udunits2.

By Matthew Fidler in rxode2

May 31, 2025