parsing speed
(just my additional $.02) ... and as a general rule (subject to numerous exceptions, caveats, etc.) 1) it is programming and debugging time that most impacts "overall" program execution time; 2) this is most strongly impacted by code readability and size (the smaller the better); 3) both of which are enhanced by modular construction and reuseability, which argues for avoiding inline code and using separate functions. These days, i would argue that most of the time it is program clarity and correctness (they are related) that is the important issue, not execution speed. ... again, subject to exceptions and caveats, etc. -- Bert Gunter Genentech Non-Clinical Statistics South San Francisco, CA "The business of the statistician is to catalyze the scientific learning process." - George E. P. Box
-----Original Message----- From: r-help-bounces at stat.math.ethz.ch [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Duncan Murdoch Sent: Monday, May 16, 2005 3:09 PM To: f.calboli at imperial.ac.uk Cc: r-help Subject: Re: [R] parsing speed Federico Calboli wrote:
Hi everyone,
I have a question on parsing speed.
I have two functions:
F1
F2
As things are now, F2 calls F1 internally:
F2 = function(x){
if (something == 1){
y = F1(x)
}
if (something ==2){
do whatever
}
}
*Assuming there could be some difference*, is is faster to
use the code
as written above or should I actually write the statements
of F1 to make
the parsing faster?
The parsing only happens once when you define the functions, and is (almost always) a negligible part of total execution time. I think you're really worried about execution time. You'll probably get more execution time with a separate function because function calls take time. However, my guess is that putting F1 inline won't make enough difference to notice. Duncan
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