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

nlmixr2 Neural Network ODEs with pmxNODE

Neural Network ODEs and nlmixr2 I have had some requests to talk about nlmixr2 using neural network ODEs, since neural networks are something that more people are exploring with the explosion of artificial intelligence LLMs. There is a package, pmxNODE, by Dominic Bräm that adds neural network ODEs to pharmacometric modeling tools like NONMEM, Monolix and nlmixr2. In addition to the code that Dominic has added, I extended this package to allow Neural Networks directly in a rxode2 or nlmixr2 model.

nlmixr2 augmented plot

This month I will on a single nlmixr2’s plot function that is shared with nlme, augPred(). I think this is useful but also harder to find like the rxode2 plots discussed last month. The example of this feature is the phenobarbitol data: library(nlmixr2) pheno <- function() { ini({ tcl <- log(0.008) # typical value of clearance tv <- log(0.6) # typical value of volume ## var(eta.cl) eta.cl + eta.v ~ c(1, 0.

By Matthew Fidler in nlmixr2

March 31, 2025