>>>>> Balasubramanian Narasimhan
>>>>> on Wed, 23 Dec 2020 08:34:40 -0800 writes:
> 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
well, glmnet's src/*.f code seems closer to assembly than to
even old fortran 77 style ..
which would not change when calling it via .Call() ...
;-)
The performance "hit" of using .Fortran is probably almost only
from the fact .C() and .Fortran() now compulsorily *copy* their
arguments, whereas with .Call() you are enabled to shoot
yourself in both feet .. ;-)
Martin
> 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$
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