[Rd] Byte code compile not helpful in R3.0.2

[Henrik Bengtsson]

tfor <- cmpfun(tfor)
twhile <- cmpfun(twhile)

/Henrik


On Sun, Nov 3, 2013 at 11:55 AM, Prof J C Nash (U30A) <nashjc at uottawa.ca> wrote:
> My bad to not give details. I'm comparing (though not quite directly) to
> results in the posting
> http://rwiki.sciviews.org/doku.php?id=tips:rqcasestudy.
>
> What prompted the query was a write up of "for" versus "while" loops,
> where there was a speedup using compiler for one of these. I had the
> example in a knitr file, and when I was reviewing the text before
> sending it to an editor, I realized the timings no longer supported the
> text. They were, as I recall, developed in R 2.15.2, and I just looked
> through my VMs with different OS's to see if there is one with that
> still extant, but except for a real Win7 case I have been too "good" and
> updated to at least 3.0.1, where I'm getting no advantage. The Win7 case
> is R 2.15.1, and there the compiler actually went slower on one run of
> the code below. That may be due to antivirus running -- had not booted
> that partition for quite a while.
>
> Here is the for-while test code:
>
> #  forwhiletime.R
> library(microbenchmark)
> require(compiler)
>
> tfor <- function(n){
>     for (i in 1:n) {
>        xx<-exp(sin(cos(as.double(i))))
>     }
>     xx
> }
>
> twhile <- function(n){
>     i<-0
>     while (i<n) {
>        i<-i+1
>        xx<-exp(sin(cos(as.double(i))))
>     }
>     xx
> }
> n<-10000
>
> timfor<-microbenchmark(tfor(n))
> timwhile<-microbenchmark(twhile(n))
> timfor
> timwhile
> cmpfun(tfor)
> cmpfun(twhile)
> timforc<-microbenchmark(tfor(n))
> timwhilec<-microbenchmark(twhile(n))
> timforc
> timwhilec
> looptimes<-data.frame(timfor$time, timforc$time, timwhile$time,
> timwhilec$time)
> colMeans(looptimes)
>
>
> Actually, I'm not greatly axious about all this. Mainly I want to make
> sure that I get whatever advice is to be rendered so it is correct.
>
> Best,
>
> JN
>
>
> On 13-11-03 02:22 PM, Duncan Murdoch wrote:
>> On 13-11-03 2:15 PM, Prof J C Nash (U30A) wrote:
>>> I had a bunch of examples of byte code compiles in something I was
>>> writing. Changed to 3.0.2 and the advantage of compiler disappears. I've
>>> looked in the NEWS file but do not see anything that suggests that the
>>> compile is now built-in. Possibly I've just happened on a bunch of
>>> examples where it does not help, but experiences of a year ago do not
>>> seem to remain valid now. Just wondering if my experience was consistent
>>> with what is expected now in 3.0.2.
>>
>> Post some details, please.  Are the times in 3.0.2 like the times in
>> 3.0.1 with or without compiling?  Or were you comparing to some other
>> version?
>>
>> Duncan Murdoch
>>
>>
>>
>
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