[R] Speeding up small functions

[Wee-Jin Goh]

Greetings list,

In my code, I have a few small functions that are called very very  
frequently. An example of one such function is the following :

sigmoid<-function(x) 1/(1+exp(-x))

Now, is there anyway to make this go faster? For example, in C++ we  
could make it inline. Is there a corresponding feature in R?

Cheers,
Wee-Jin