I need to compare two functions in terms of elapsed time. At the moment I am using the following code:
system.time(f1())
system.time(f2())
And if I want to run the same functions multiple times I use:
system.time(replicate(10, f1()))
system.time(replicate(10, f2()))
The information that I get from system.time is user, system and elapsed time.
The point is that I would know, if I replicate the function, also the min and max elapsed time of the single call.
How can I do?
If you are not constrained by using only base packages, I would suggest using microbenchmark package.
> f1 <- function() 1
> f2 <- function() 2
> microbenchmark::microbenchmark(f1(), f2(), times = 10)
Unit: nanoseconds
expr min lq mean median uq max neval cld
f1() 134 195 896.7 309 360 6418 10 a
f2() 133 138 305.3 189 230 1320 10 a
However, if you still want to use system.time, just move replicate outside of system.time call. For example,
> f1 <- function() sapply(1:100000, identity)
> times <- replicate(10, system.time(f1())[3])
> min(times)
[1] 0.051
> max(times)
[1] 0.057
