Dr Murdoch, You're absolutely correct -- my apologies.
Michael On Thu, Nov 10, 2011 at 10:44 AM, Duncan Murdoch <murdoch.dun...@gmail.com> wrote: > On 10/11/2011 10:28 AM, R. Michael Weylandt wrote: >> >> Yes, there will be some reduction in speed: >> >> E.g., >> >> > system.time(replicate(1e5, (function() sum(1:10))())) >> user system elapsed >> 0.696 0.022 0.729 >> > system.time(replicate(1e5, sum(1:10))) >> user system elapsed >> 0.292 0.006 0.306 >> >> But it's not much: 3 tenths of a second for 10,000 calls. It's >> certainly worth it for ease of readibility and debugging. > > I don't think your test is valid: you're not just calling the function in > the upper loop, you're creating it too. Here's what I see: > > First, the version I complained about: > >> system.time(replicate(1e5, (function() sum(1:10))())) > user system elapsed > 0.35 0.00 0.35 > > Now a more realistic one: > >> f <- function() sum(1:10) >> system.time(replicate(1e5, f())) > user system elapsed > 0.25 0.00 0.25 > > Now the version with no function call: > >> system.time(replicate(1e5, sum(1:10))) > user system elapsed > 0.23 0.00 0.24 > > > So creating a function is expensive, but calling one isn't so bad. > > Duncan Murdoch > ______________________________________________ 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.
