The principle R implementation is written in R, C, and Fortran, and there are various other implementations geared toward improving speed or growing extensibility. A closely associated implementation is pqR (very quick R) by Radford M. Neal with enhanced memory administration and guidance for computerized multithreading. Renjin and FastR http://knoxwlzpb.mybloglicious.com/2485408/new-step-by-step-map-for-online-programming-assignment-service