Thanks to all and best wishes for a better 2021.
Unfortunately I remain somewhat confused:
o Bill reveals an elegant way to get from my rudimentary registration setup
to
one that would explicitly type the C interface functions,
o Ivan seems to suggest that there would be no performance gain from doing
this.
o Naras?s pcLasso package does use the explicit C typing, but then uses
.Fortran
not .Call.
o Avi uses .Call and cites the Romp package
https://github.com/wrathematics/Romp
where it is asserted that "there is a (nearly) deprecated interface
.Fortran() which you
should not use due to its large performance overhead.?
As the proverbial naive R (ab)user I?m left wondering:
o if I updated my quantreg_init.c file in accordance with Bill?s suggestion
could I
then simply change my .Fortran calls to .Call?
o and if so, do I need to include ALL the fortran subroutines in my src
directory
or only the ones called from R?
o and in either case could I really expect to see a significant performance
gain?
Finally, perhaps I should stipulate that my fortran is strictly f77, so no
modern features
are in play, indeed most of the code is originally written in ratfor, Brian
Kernighan?s
dialect from ancient times at Bell Labs.
Again, thanks to all for any advice,
Roger
> On Dec 23, 2020, at 1:11 AM, Avraham Adler <avraham.adler at
gmail.com> wrote:
>
> Hello, Ivan.
>
> I used .Call instead of .Fortran in the Delaporte package [1]. What
> helped me out a lot was Drew Schmidt's Romp examples and descriptions
> [2]. If you are more comfortable with the older Fortran interface,
> Tomasz Kalinowski has a package which uses Fortran 2018 more
> efficiently [3]. I haven't tried this last in practice, however.
>
> Hope that helps,
>
> Avi
>
> [1]
https://urldefense.com/v3/__https://CRAN.R-project.org/package=Delaporte__;!!DZ3fjg!s1-ihrZ9DPUtXpxdIpJPA1VedpZFt12Ahmn4CycOmile_uSahFZnJPn_5KPITBN5NK8$
> [2]
https://urldefense.com/v3/__https://github.com/wrathematics/Romp__;!!DZ3fjg!s1-ihrZ9DPUtXpxdIpJPA1VedpZFt12Ahmn4CycOmile_uSahFZnJPn_5KPISF5aCYs$
> [3]
https://urldefense.com/v3/__https://github.com/t-kalinowski/RFI__;!!DZ3fjg!s1-ihrZ9DPUtXpxdIpJPA1VedpZFt12Ahmn4CycOmile_uSahFZnJPn_5KPIbwXmXqY$
>
> Tomasz Kalinowski
>
>
>
> On Tue, Dec 22, 2020 at 7:24 PM Balasubramanian Narasimhan
> <naras at stanford.edu> wrote:
>>
>> To deal with such Fortran issues in several packages I deal with, I
>> wrote the SUtools package
(https://urldefense.com/v3/__https://github.com/bnaras/SUtools__;!!DZ3fjg!s1-ihrZ9DPUtXpxdIpJPA1VedpZFt12Ahmn4CycOmile_uSahFZnJPn_5KPIJ5BbDwA$
) that you
>> can try. The current version generates the registration assuming
>> implicit Fortran naming conventions though. (I've been meaning to
>> upgrade it to use the gfortran -fc-prototypes-external flag which
should
>> be easy; I might just finish that during these holidays.)
>>
>> There's a vignette as well:
>>
https://urldefense.com/v3/__https://bnaras.github.io/SUtools/articles/SUtools.html__;!!DZ3fjg!s1-ihrZ9DPUtXpxdIpJPA1VedpZFt12Ahmn4CycOmile_uSahFZnJPn_5KPITq9-Quc$
>>
>> -Naras
>>
>>
>> On 12/19/20 9:53 AM, Ivan Krylov wrote:
>>> On Sat, 19 Dec 2020 17:04:59 +0000
>>> "Koenker, Roger W" <rkoenker at illinois.edu>
wrote:
>>>
>>>> There are comments in various places, including R-extensions
?5.4
>>>> suggesting that .Fortran is (nearly) deprecated and hinting
that use
>>>> of .Call is more efficient and now preferred for packages.
>>> My understanding of ?5.4 and 5.5 is that explicit routine
registration
>>> is what's important for efficiency, and your package already
does that
>>> (i.e. calls R_registerRoutines()). The only two things left to add
>>> would be types (REALSXP/INTSXP/...) and styles (R_ARG_IN,
>>> R_ARG_OUT/...) of the arguments of each subroutine.
>>>
>>> Switching to .Call makes sense if you want to change the interface
of
>>> your native subroutines to accept arbitrary heavily structured
SEXPs
>>> (and switching to .External could be useful if you wanted to play
with
>>> evaluation of the arguments).
>>>
>>
>> ______________________________________________
>> R-devel at r-project.org mailing list
>>
https://urldefense.com/v3/__https://stat.ethz.ch/mailman/listinfo/r-devel__;!!DZ3fjg!s1-ihrZ9DPUtXpxdIpJPA1VedpZFt12Ahmn4CycOmile_uSahFZnJPn_5KPIr_nqkqg$