[Rd] Byte code compile (not) helpful in R3.0.2 -- Fixed.

[Prof J C Nash (U30A)]

Thanks. I should not try adjusting code after some hours of proofreading.

Making that change gave a suitable time difference.

Best, JN



On 13-11-03 03:46 PM, Henrik Bengtsson wrote:
> 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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