On 27-08-2023 21:02, Ivan Krylov wrote:
On Sun, 27 Aug 2023 19:54:23 +0100
John Logsdon <j.logs...@quantex-research.com> wrote:
Not so although it did lower the gc() time to 95.84%.
This was on a 16 core Threadripper 1950X box so I was intending to
use library parallel but I tried it on my lowly windows box that is
years old and got it down to 88.07%.
Does the Windows box have the same version of R on it?
Yes, they are both 4.3.1
The only thing I can think of is that there are quite a lot of cases
where a function is generated on the fly as in:
eval(parse(t=paste("dprob <-
function(x,l,s){",dist.functions[2,][dist.functions[1,]==distn],"(x,l,s)}",sep="")))
This isn't very idiomatic. If you need dprob to call the function named
in dist.functions[2,][dist.functions[1,]==distn], wouldn't it be easier
for R to assign that function straight to dprob?
dprob <- get(dist.functions[2,][dist.functions[1,]==distn])
This way, you avoid the need to parse the code, which is typically not
the fastest part of a programming language.
(Generally in R and other programming languages with recursive data
structures, storing variable names in other variables is not very
efficient. Why not put functions directly into a list?)
Agreed but this statement and other similar ones are only assigned once
in an outer loop.
Rprof() samples the whole call stack. Can you find out which functions
result in a call to gc()? I haven't experimented with a wide sample of
R code, but I don't usually encounter gc() as a major entry in my
Rprof() outputs.
From the first table, removing all the system functions, it suggests
that the function do.combx() is mainly guilty. I have recoded that and
gc() no longer appears - as it shouldn't with it switched off! One
difference was that the new code used the built in combn function while
the old code used gtools::combinations. I need gtools::permutations
elsewhere but that is not time critical.
Thanks Ivan for making me think!
--
John Logsdon
Quantex Research Ltd
m:+447717758675/h:+441614454951
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.
