The key R implementation is published in R, C, and Fortran, and there are plenty of other implementations geared toward enhancing speed or raising extensibility. A closely related implementation is pqR (quite rapid R) by Radford M. Neal with enhanced memory management and help for automatic multithreading. Renjin and http://kylersbhjk.blog2learn.com/22017178/r-programming-project-help-can-be-fun-for-anyone