Re: [R] R-Fortran question (multiple subroutines)
G'day Remko, On Mon, 25 Oct 2010 15:33:30 +1100 Remko Duursma remkoduur...@gmail.com wrote: apologies if this is somewhere in a manual, I have not been able to find anything relevant. You probably have to set some appropriate flags and the information should be somewhere in the manual of your compiler. Though, Writing R Exensions will tell you now to change/specify flags for compilers. I run Windows Vista. My condolences. :) But is it possible to have more than one subroutine in my source file, one depending on the other? Yes. I.e, my code looks something like this: subroutine f(x,y,z) call g(x,y,z) end subroutine g(x,y,z) z = x*y end calling this from R shows that subroutine g is not called. What do you mean with g is not called? How did you assert this? If the code functions correctly, then g has to be called, either explicitly or implicitly (e.g. if it was inlined). Do you mean that when you compile the code and load the resulting DLL from R, you can only call subroutine f via .Fortran but not subroutine g? The code compiled as executable works fine. What do you mean with compiled as executable? The snippet that you showed would not compile as an executable as there is no main program. So what do you mean with works fine? That you can call the subroutine g from the main program that you use when creating an executable? My guess, based on this snippet, is that your compiler notices that subroutine g is not really needed and replaces the call to g within f by the body of g and does not create a separate entry point for g in the compiled object; a process known as in-lining (IIRC) and typically used by compilers if high levels of optimisations are requested. The compiler does not know that you intend to call g later directly from R via .Fortran, all it sees is the code in the file and, if high optimisation is requested, it may feel free to rearrange the code to stream-line it (e.g. by in-lining). So possible solutions could be: 1) ask for a lower level of optimisation 2) tell the compiler not to do in-lining (flag --no-inline??) 3) put the routines into separate files, compile the files separately and then link all the resulting object files together into a DLL. AFAIK, optimising/inlining across separate files is a tricky issue so few, if any, compilers would do so. 4) Check whether there is an option to specify which exportable symbols have to be in the DLL in the end. Cheers, Berwin == Full address Berwin A Turlach Tel.: +61 (8) 6488 3338 (secr) School of Maths and Stats (M019)+61 (8) 6488 3383 (self) The University of Western Australia FAX : +61 (8) 6488 1028 35 Stirling Highway Crawley WA 6009e-mail: ber...@maths.uwa.edu.au Australiahttp://www.maths.uwa.edu.au/~berwin __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] R-Fortran question (multiple subroutines)
Remko Duursma wrote: Dear R-helpers, apologies if this is somewhere in a manual, I have not been able to find anything relevant. I run Windows Vista. I have some Fortran code in a subroutine, and have no problem calling this from R with .Fortran, compiling the code either with 'R CMD SHLIB' or independently with gfortran. But is it possible to have more than one subroutine in my source file, one depending on the other? Or is this not supported, or is there a trick? Of course, I could rewrite my code, but there are lots of subroutines... I.e, my code looks something like this: subroutine f(x,y,z) call g(x,y,z) end subroutine g(x,y,z) z = x*y end calling this from R shows that subroutine g is not called. The code compiled as executable works fine. There are no such limitations imposed by R. I'd suggest your diagnosis of the problem is wrong. If you can't spot the problem, please post a real example (simplified if possible, but not as much as the one above). Duncan Murdoch thanks, Remko - Remko Duursma Research Lecturer Centre for Plants and the Environment University of Western Sydney Hawkesbury Campus Richmond NSW 2753 Mobile: +61 (0)422 096908 www.remkoduursma.com __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] R-Fortran question (multiple subroutines)
G'day all, On Mon, 25 Oct 2010 06:52:15 -0400 Duncan Murdoch murdoch.dun...@gmail.com wrote: Remko Duursma wrote: [...] I.e, my code looks something like this: subroutine f(x,y,z) call g(x,y,z) end subroutine g(x,y,z) z = x*y end calling this from R shows that subroutine g is not called. The code compiled as executable works fine. There are no such limitations imposed by R. I'd suggest your diagnosis of the problem is wrong. If you can't spot the problem, please post a real example (simplified if possible, but not as much as the one above). Actually, it turns out that this example is simplified enough. :) I put this snippet into a file, compiled it via R CMD SHLIB, loaded it into R and then was very surprised about the result of .Fortran(f, x=1.1, y=2.2, z=0.0). Eventually it dawned to me, Remko needs to read the table in section 5.2 of Writing R Extensions. The simple fix in this case is to put a double precision x, y, z at the beginning of each subroutine. The default precision in FORTRAN is not double precision, that's why the code seems to work when compiled as stand alone but not when called from R. In general, I would recommend to start each subroutine with implicit none (o.k., I know that this is not standard FORTRAN77 but most compiler support that construct; the alternative, that would confrom with the FORTRAN77 standard, is to declare everything to be implicitly of type character and then let the fun begin) and then to explicitly declare all variables to be of the appropriate type. HTH. Cheers, Berwin __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] R-Fortran question (multiple subroutines)
Berwin A Turlach wrote: Remko Duursma wrote: [...] I.e, my code looks something like this: subroutine f(x,y,z) call g(x,y,z) end subroutine g(x,y,z) z = x*y end calling this from R shows that subroutine g is not called. The code compiled as executable works fine. There are no such limitations imposed by R. I'd suggest your diagnosis of the problem is wrong. If you can't spot the problem, please post a real example (simplified if possible, but not as much as the one above). Actually, it turns out that this example is simplified enough. :) I put this snippet into a file, compiled it via R CMD SHLIB, loaded it into R and then was very surprised about the result of .Fortran(f, x=1.1, y=2.2, z=0.0). Eventually it dawned to me, Remko needs to read the table in section 5.2 of Writing R Extensions. The simple fix in this case is to put a double precision x, y, z at the beginning of each subroutine. The default precision in FORTRAN is not double precision, that's why the code seems to work when compiled as stand alone but not when called from R. In general, I would recommend to start each subroutine with implicit none (o.k., I know that this is not standard FORTRAN77 but most compiler support that construct; the alternative, that would confrom with the FORTRAN77 standard, is to declare everything to be implicitly of type character and then let the fun begin) and then to explicitly declare all variables to be of the appropriate type. I alway look for a command line option for the fortran compiler to achieve the implicit none. gfortran has the option -fimplicit-none. I try to always use it. For R package building I start out with using the implicit-none option and comment it out in the makevars only in the final stage when R warns me about non standard options. Berend -- View this message in context: http://r.789695.n4.nabble.com/R-Fortran-question-multiple-subroutines-tp3009729p3010385.html Sent from the R help mailing list archive at Nabble.com. __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] R-Fortran question (multiple subroutines)
Hi Berwin and all others who replied: that did the trick, thanks for your help! remko Actually, it turns out that this example is simplified enough. :) I put this snippet into a file, compiled it via R CMD SHLIB, loaded it into R and then was very surprised about the result of .Fortran(f, x=1.1, y=2.2, z=0.0). Eventually it dawned to me, Remko needs to read the table in section 5.2 of Writing R Extensions. The simple fix in this case is to put a double precision x, y, z at the beginning of each subroutine. The default precision in FORTRAN is not double precision, that's why the code seems to work when compiled as stand alone but not when called from R. In general, I would recommend to start each subroutine with implicit none (o.k., I know that this is not standard FORTRAN77 but most compiler support that construct; the alternative, that would confrom with the FORTRAN77 standard, is to declare everything to be implicitly of type character and then let the fun begin) and then to explicitly declare all variables to be of the appropriate type. HTH. Cheers, Berwin __ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
