Now that Rcpp got updated to 0.8.6, we have an updated RcppArmadillo release containing mostly updates to Conrad’s Armadillo version 0.9.70 as well as some more templated sugar magic. RcppArmadillo makes it easy to write highly efficient and highly readable C++ code for linear algebra (based on Armadillo) in R extensions (using Rcpp for the interface).
The short NEWS file extract follows:
0.2.6 2010-09-12 o Upgraded to Armadillo 0.9.70 "Subtropical Winter Safari" o arma::Mat, arma::Row and arma::Col get constructor that take vector or matrix sugar expressions. See the unit test "test.armadillo.sugar.ctor" and "test.armadillo.sugar.matrix.ctor" for examples.