# Dissecting lme4's lmer function. Part 3.

This is the final part of my analysis of the function `lmer`

, which is used to fit linear mixed models in the R package `lme4`

. In two previous blog posts, we have seen the general layout of the function `lmer`

, the dealings with the R model formula, and the setting up of the objective function for the optimization (see part 1 and part 2).