Linear Mixed Models with Sparse Matrix Methods and Smoothing R package LMMsolver version 1.0.12 Provides tools for fitting linear mixed models using sparse matrix methods and variance component estimation. Applications include spline-based modeling of spatial and temporal trends using penalized splines (Boer, 2023) <doi:10.1177/1471082X231178591>. Software Depends: R (>= 3.6) Imports: Matrix, methods, Rcpp (>= 0.10.4), spam, splines LinkingTo: Rcpp Suggests: rmarkdown, knitr, tinytest, tidyr, ggplot2, maps, sf Bart-Jan van Rossum <bart-jan.vanrossum@wur.nl> Comprehensive R Archive Network (CRAN) Martin Boer [aut] (ORCID: <https://orcid.org/0000-0002-1879-4588>), Bart-Jan van Rossum [aut, cre] (ORCID: <https://orcid.org/0000-0002-8673-2514>) GPL-3 2025-12-05 application/tgz https://CRAN.R-project.org/package=LMMsolver doi:10.32614/CRAN.package.LMMsolver