tfor <- cmpfun(tfor) twhile <- cmpfun(twhile) /Henrik
On Sun, Nov 3, 2013 at 11:55 AM, Prof J C Nash (U30A) <nas...@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 >> >> >> > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
