Thanks for this optimization and for adding it to R-devel. My
original command on the glibc 2.3.3 machine now runs much faster:
> system.time(x <- as.Date(rep("01-01-2005", 100000), format = "%m-%d-%Y"))
[1] 0.97 0.91 1.88 0.00 0.00
and is in line with the time seen on the glibc 2.3.2 machine.
Jeff
Prof Brian Ripley writes:
> On Thu, 5 May 2005, Peter Dalgaard wrote:
>
> > Jeff Enos <[EMAIL PROTECTED]> writes:
> >
> >> Thanks for these suggestions. C-level profiling yields the following:
> >>
> >> % cumulative self self total
> >> time seconds seconds calls s/call s/call name
> >> 36.01 5.34 5.34 100000 0.00 0.00 get_locale_strings
> >> 4.32 5.98 0.64 100000 0.00 0.00 mktime00
> >> 3.98 6.57 0.59 277462 0.00 0.00 Rf_eval
> >> 3.71 7.12 0.55 472935 0.00 0.00 Rf_findVarInFrame3
> >> 3.64 7.66 0.54 100000 0.00 0.00 strptime_internal
> >> 3.51 8.18 0.52 1 0.52 7.51 do_strptime
> >>
> >> It looks like strftime is called from get_locale_strings, which might
> >> be the culprit. Any suggestions on where I might go from here?
> >
> > You might try modifying get_locale_strings (and its wide counterpart)
> > with a check for an unchanged locale. E.g.
> >
> > static char *last_LC_TIME=NULL;
> >
> > ....
> >
> > tmp = setlocale(LC_TIME, NULL)
> > if (strcmp(tmp, last_LC_TIME)) return;
> >
> > last_LC_TIME = tmp;
> >
> > .... set the strings ....
> >
> > if the call to setlocale is considerably faster than 40 calls to
> > strftime(), you might have a winner.
>
> Yes, I think that would be a worthwhile optimization. I didn't bother
> because I figured it would be fast enough (which at 50musec it almost
> always is).
>
> However, get_locale_strings is only 36% of the total, and we have at least
> another 60% to account for. (81.01 vs 1.18 secs.)
>
> --
> 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
--
Jeff Enos
Kane Capital Management
[EMAIL PROTECTED]
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