[R] Measuring CPU time

[Gabor Grothendieck]

On Thu, Sep 1, 2011 at 8:10 AM, . . <xkziloj at gmail.com> wrote:
> Why time is increasing for the same operation?
>
> I was expecting +/- the same time for each n.
>
> Thanks in advance.
>
> bench <- function(f1, n, ...) {
>  t <- 0
>  for(i in 1:n) {
>    func <- function(x) x^2
>    expr <- list(...)[1]
>    f1 <- c("system.time(y <- ", gsub("XXX",expr,f1),")[3]")
>    t1 <- eval(parse(text = f1))
>    printf("time %d: %f\n", i, t1)
>    t <- t + t1
>  }
>  t <- t/n
>  printf("mean time: %f", t)
> }
> bench("func(XXX)", 10, "1:100")
>

On each iteration f1 gets larger.  (Also printf is not defined.)

Check out the rbenchmark package.

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