ardea
ardea has been recently submitted to CRAN and combines work that was originally performed with metal and CUDA separately, and tooling for users to interface with OpenCL. ardea’s goal is to provide reliable and uniform access to non-CPU compute devices for R users in familiar R-ish patterns. It is currently somewhat limited in functionality, but provides reliable and robust tooling for incorporating GPU function dispatch into in ad-hoc scripts or functions. ardea should install anywhere R will install, but it will only compile tooling for frameworks it can detect during installation.
This is still a work in progress, and is a bit of a free-time project. If it is accepted to CRAN, the next steps for ardea will focus on expanding functionality to cover realistic use-cases for R package developers.