The summary of the main changes follows:
Courtesy of CRANberries, there is also a diffstat report for the most recent release As always, more detailed information is on the RcppArmadillo page. Questions, comments etc should go to the rcpp-devel mailing list off the R-Forge page.
Changes in RcppArmadillo version 0.3.820 (2013-05-12)
Upgraded to Armadillo release Version 3.820 (Mt Cootha)
as_scalar()for compound expressions
faster transpose of small vectors
faster matrix-vector product for small vectors
faster multiplication of small fixed size matrices