On Mon, Nov 1, 2010 at 10:12 AM, Megh Dal <megh700...@yahoo.com> wrote: > Dear friend, I have to construct some recursive algorithm for which I used > some for loop like: > > res <- vector(length=10000) > res[1] = 0 > for (i in 2:(10000+1)) res[i] <- res[i-1]*........some function > > I have noticed that this is taking too much time. Is there any way to speed > up things?
You can't speed ANYTHING up until you know where the time is going. In your case, is it in "some function" or in R's loop. Try replacing 'some function' with a constant and see what happens. I suspect it will be very quick. > system.time(for (i in 2:(10000+1)) res[i] <- res[i-1]*1.12) user system elapsed 0.076 0.000 0.077 yup. So it's all in 'some function'. Next question? Barry ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
