Greetings R developers! I have been working on a just-in-time compiler for R arithmetic expressions. An example: jit(1) # turn on just-in-time compilation for(i in 1:na) # example convolution code for(j in 1:nb) ab[i + j] <- ab[i + j] + a[i] * b[j] The loop will run about 30% faster. That's not much of a speedup, but the code is still in early development and the figure will get much better. If you are interested there is more information at www.milbo.users.sonic.net/ra. Stephen Milborrow www.milbo.users.sonic.net