Hi. I haven't tested the speed of the old .Fortran interface, but in this post [1] I describe how to build a simple interface (there are two small packages on github that correspond to the code) and in this one [2] I compare the speed of the different languages, but all using .Call.
Hope that helps, Avi [1] https://www.avrahamadler.com/2018/12/09/the-need-for-speed-part-1-building-an-r-package-with-fortran/ [2] https://www.avrahamadler.com/2018/12/23/the-need-for-speed-part-2-c-vs-fortran-vs-c/ On Wed, Dec 23, 2020 at 11:34 AM Balasubramanian Narasimhan <na...@stanford.edu> wrote: > > I think it should be pretty easy to fix up SUtools to use the .Call > instead of .Fortran following along the lines of > > https://github.com/wrathematics/Romp > > I too deal with a lot of f77 and so I will most likely finish it before > the new year, if not earlier. (Would welcome testers besides myself.) > > Incidentally, any idea of what the performance hit is, quantitatively? I > confess I never paid attention to it myself as most Fortran code I use > seems pretty fast, i.e. glmnet. > > -Naras > > > On 12/23/20 3:57 AM, Koenker, Roger W wrote: > > 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.ad...@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 > >> <na...@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" <rkoen...@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@r-project.org mailing list > >>> https://urldefense.com/v3/__https://stat.ethz.ch/mailman/listinfo/r-devel__;!!DZ3fjg!s1-ihrZ9DPUtXpxdIpJPA1VedpZFt12Ahmn4CycOmile_uSahFZnJPn_5KPIr_nqkqg$ ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
