[R-pkg-devel] R, BLAS, and FCLEN (solved)
Göran Broström
gor@n@bro@trom @end|ng |rom umu@@e
Fri Sep 13 00:07:15 CEST 2019
On 2019-09-12 09:13, Martin Maechler wrote:
>>>>>> Göran Broström
>>>>>> on Wed, 11 Sep 2019 13:36:40 +0200 writes:
>
> > A followup question: Is it possible to call a BLAS/LAPACK subroutine,
> > where one parameter is character, from FORTRAN (77) code called by
> > .Fortran? (No problem "in the past".)
>
> [as there wasn't a reply till now : ]
>
> Yes, that should continue to be possible.
>
> > And if yes, how?
>
> I'm sorry I don't know (and currently lack the time to try to find out)...
I solved it by writing a C wrapper (for the BLAS subroutine dgemv) cdgemv:
#define USE_FC_LEN_T
#include <Rconfig.h>
#include <R_ext/BLAS.h>
#ifndef FCONE
# define FCONE
#endif
#include <R.h>
#include "cdgemv.h"
void F77_SUB(cdgemv)(const int *trans, const int *m, const int *n,
const double *alpha, const double *a,
const int *lda,
const double *x, const int *incx,
const double *beta,
double *y, const int *incy){
char trams;
if (*trans == 1){
trams = 'N';
F77_CALL(dgemv)(&trams, m, n, alpha, a, lda, x, incx, beta, y,
incy FCONE);
}else
Rprintf("trans has wrong value\n");
}
}
which I call from Fortran. Curiously, a Fortran wrapper also seems to work.
G,
>
> Martin
>
> > Documentation describes calls from C to Fortran and
> > vice versa, but not this situation (AFAICS).
>
> > Yes, I know that .Fortran is not well seen these days, but my fortran
> > code is ancient, from the before-R era, and I would like to leave it as-is.
>
> > G,
>
> > Den 2019-09-01 kl. 21:46, skrev Göran Broström:
> >>
> >>
> >> On 2019-08-31 18:47, Göran Broström wrote:
> >>> I'm having difficulties updating my package eha: When I run standard
> >>> checks 'at home' everything is fine, but 'CRAN-submissions' reports
> >>> (among other things):
> >>>
> >>> geomsup.f:324:9: warning: type of ‘dgemv’ does not match original
> >>> declaration [-Wlto-type-mismatch]
> >>> 324 | & one, score, ione)
> >>> | ^
> >>> /home/tmp/R-d-gcc-LTO/include/R_ext/BLAS.h:107:1: note: type mismatch
> >>> in parameter 12
> >>> 107 | F77_NAME(dgemv)(const char *trans, const int *m, const int *n,
> >>> | ^
> >>>
> >>> This is odd since the LAPACK subroutine dgemv takes only 11
> >>> parameters. However, in include/R_ext/BLAS.h we have
> >>>
> >>> F77_NAME(dgemv)(const char *trans, const int *m, const int *n,
> >>> const double *alpha, const double *a, const int *lda,
> >>> const double *x, const int *incx, const double *beta,
> >>> double *y, const int *incy FCLEN);
> >>>
> >>> with a 12th parameter FCLEN?? How am I supposed to fix this, and what
> >>> the ... is FCLEN? googling leads to nothing useful (for me). It seems
> >>> as if R is redefining some standard LAPACK routines.
> >>>
> >>> Also a note I do not understand (in this context):
> >>>
> >>> note: type ‘void’ should match type ‘long int’
> >>>
> >>> Any help is much appreciated.
> >>>
> >>> Best, Göran
> >>>
> >>> PS. How can I trigger these Warnings 'at home'?
> >>
> >> See https://www.stats.ox.ac.uk/pub/bdr/LTO/README.txt (thanks to Uwe
> >> Ligges).
> >>
> >> Another relevant document seems to be (2019-05-15):
> >>
> >> https://developer.r-project.org/Blog/public/2019/05/15/gfortran-issues-with-lapack/index.html
> >>
> >>
> >> First sentence:
> >> "Recent version of the GNU Fortran compiler (7, 8, 9) include
> >> optimizations that break interoperability between C and Fortran code
> >> with BLAS/LAPACK."
> >>
> >> And later:
> >> "For the time being, everyone should use -fno-optimize-sibling-calls
> >> with GFortran version 7 and newer."
> >>
> >> G,
> >>
> >>> ______________________________________________
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> >>> https://stat.ethz.ch/mailman/listinfo/r-package-devel
> >>
> >> ______________________________________________
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>
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