[R] Why is looping in R inefficient, but in C not?

Hey, I just read another post about calling R from C. Someone on stackoverflow (DWin makes me suspect its David W.?) referenced this: http://www.math.univ-montp2.fr/~pudlo/R_files/call_R.pdf Which made me think: Why is a loop in R bad, but in C not? And where exactly does looping cost the

Re: [R] Why is looping in R inefficient, but in C not?

For the same reason the Cray XMP was fast at numerical computations... a loop written in a low level language can be optimized to work faster than one written in a higher level language. The XMP optimized loops into hardware, but R just optimizes them in C code, exposed to the R programmer as

Re: [R] Why is looping in R inefficient, but in C not?

Probably the easiest way to think about it is that most of the extra time is the overhead of calling a function. So counting the number of calls to R functions is going to tell you how much overhead there is. (Remember that functions call other functions.) On 26/06/2011 08:21, Jeff Newmiller

Re: [R] Why is looping in R inefficient, but in C not?

On Jun 26, 2011, at 2:56 AM, Alexander Engelhardt wrote: Hey, I just read another post about calling R from C. Someone on stackoverflow (DWin makes me suspect its David W.?) referenced this: http://www.math.univ-montp2.fr/~pudlo/R_files/call_R.pdf Which made me think: Why is a loop in R