A new release 0.3.3.9.1 of RcppEigen arrived on CRAN today (and just went to Debian too) bringing support for Eigen 3.3.9 to R. Eigen is a C++ template library for linear algebra: matrices, vectors, numerical solvers, and related algorithms.

The release started with a gentle nudge from the Stan team to <a href=“https://github.com/R