On Wed, 27 Feb 2008, Martin Maechler wrote:
> Thank you Henrik,
>
>>>>>> "HenrikB" == Henrik Bengtsson <[EMAIL PROTECTED]>
>>>>>> on Tue, 26 Feb 2008 22:03:24 -0800 writes:
>
> {with many superfluous empty statements ( i.e., trailing ";" ):
Indeed!
> HenrikB> x <- rnorm(1e6);
>
> [................]
>
>
> HenrikB> y <- log2(x); # or log10(x)
> HenrikB> w <- warnings();
> HenrikB> print(object.size(w));
> HenrikB> ## [1] 8000536
> HenrikB> str(w);
> HenrikB> ## List of 1
> HenrikB> ## $ NaNs produced: language log(c(2.12082478659910,
> HenrikB> 1.40263187453398, 1.574125429
> HenrikB> ## 83486, -0.816399069824751, 0.215940065840533,
> 1.20975177084379,
> HenrikB> -0.340287874362
> HenrikB> ## 813, 0.117151537611550, ...
> HenrikB> ## - attr(*, "dots")= list()
> HenrikB> ## - attr(*, "class")= chr "warnings"
>
> HenrikB> Note also how long it takes to display and str() the warning.
>
> Yes, indeed.
> It's a subtle problem and happens
> because in do_log1arg() a new call is constructed in which 'x'
> has already been evaluated.
>
> A subtle fix to the subtle problem
> is to replace CAR(args) by CADR(call) in there
>
> --- arithmetic.c (Revision 44626)
> +++ arithmetic.c (working copy)
> @@ -1372,7 +1372,9 @@
> if(PRIMVAL(op) == 10) tmp = ScalarReal(10.0);
> if(PRIMVAL(op) == 2) tmp = ScalarReal(2.0);
>
> - PROTECT(Call = lang3(install("log"), CAR(args), tmp));
> + /* CADR(call) instead of CAR(args), since 'args' have been
> + * evaluated in Dispatch*(..) above : */
> + PROTECT(Call = lang3(install("log"), CADR(call), tmp));
> res = eval(Call, env);
> UNPROTECT(1);
> return res;
>
> -----
>
> That does fix the problem you've reported (and passes "make check")
> but I'm not quite at ease with it, since it will lead to
> effectively evaluate the argument *twice*.
>
> A different approach that I'd find cleaner
> would be to *not* construct and eval() a
> new Call inside do_log1arg, but I assume there had been a good
> reason for doing things they way they are now...
There was (although possibly no longer -- there was a bug in S4 dispatch
of primitives that failed to re-promise args).
The real issue is somewhere else entirely, the complete deparse in
print.warnings.
>
> Martin Maechler, ETH Zurich
>
> ______________________________________________
> R-devel@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
--
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
______________________________________________
R-devel@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel
