This drat package repository provides RcppMLPACK packages. In particular it used for pre-release of RcppMLPACK2 which is based on MLPACK version 2.* which is not on CRAN
# first add the repo
drat::addRepo("RcppMLPACK")
# either install just one or more given packages
install.packages("RcppMLPACK")
# or update already installed packages
update.packages()
Packages in this repository are available under their respective license, which is generally GPL version 2 or newer.