On Sun, 2 Apr 2006, Federico Calboli wrote: > is there any general advice about speeding up recursive functions > (not mentioning 'don't use them')?
Well, that's very general (did you mean recursive functions in R or C or what?). Recursion is not particularly slow in R, and you are limited to a depth of a most a few thousand. E.g.: > f <- function(x) if(x > 0) f(x-1) > system.time(for(i in 1:100) f(2000)) [1] 0.59 0.00 0.60 NA NA which is 3 usec per call. One piece of advice is to keep memory usage down, as in many of the examples I have looked at the speed issue was actually a memory issue, with datasets being copied at each level. -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
