Sorry, forgot to switch the header to the R group....
--- Globe Trotter <itsme_410 at yahoo.com> wrote:
> Date: Thu, 2 Mar 2006 19:35:21 -0800 (PST)
> From: Globe Trotter <itsme_410 at yahoo.com>
> Subject: Re: [R] calling R's library using C
> To: Dirk Eddelbuettel <edd at debian.org>
>
> Hi, Dirk:
>
> Thanks for all the help. I thought I would clarify certain things. First, I
> did
> not read that section of the manual (no one provided the pertinent link),
but
> I
> did try out that example that you suggested. It is also in
> R.2.2.1/src/nmath/standalone. However, and this is where I got misled,
> Professor Ripley's caustic statement that I should have had the
functions in
> libR.so (but I did not know where to look) led me astray. I am sure it is
all
> my fault. Anyway, the fact of the matter is that because if I include that
> library (and define that MATH_STANDALONE), I get errors: in particular, it
> would not recognize set_seed (which is a function which should work only if
> that is included). So, something was clearly long. After spending all of
> Thursday on this, I decided to post back.
>
> Thanks again for your missive. While I would appreciate the pertinent
manual
> (English is not my strong suit, but I can follow there, I am sure): btw, I
do
> not have the /usr/share/doc/r-mathlib/ directory, nor is it anywhere on my
> system (as per the output to locate), I really thank you for all your help!
I
> am sure Professor Ripley would also appreciate your support.
>
>
> --- Dirk Eddelbuettel <edd at debian.org> wrote:
>
> >
> > (whitespace trimmed)
> >
> > On 2 March 2006 at 13:42, Globe Trotter wrote:
> > | Thanks, everyone for all the help! So, here is my calling function
in C
> > | (called
> > | test.c):
> > |
> > | #include<stdio.h>
> > | #include<stdlib.h>
> > | #include<Rmath.h>
> > |
> > | int main(void) {
> > | printf("%f \n",pchisq(2.,7., 1, 0));
> > | printf("%f \n",pnchisq(2.,7.,0., 1, 0));
> > | return EXIT_SUCCESS;
> > | }
> > |
> > | I compile using:
> > |
> > | gcc test.c -I/usr/lib/R/include -L/usr/lib/R/lib -lm -lR
> > |
> > | However, running
> > | ./a.out
> > |
> > | gives me:
> > |
> > | 1.000000
> > | 0.040160
> > |
> > | The first is wrong, but the second non-central is correct, and
matches
> the
> > | answer from R.
> > |
> > | Incidentally, pgamma (which is what pchisq calls, as per the C
program
> > inside
> > | R) is also wrong and not surprisingly, gives the same answer as
above.
> > |
> > | Any suggestions?
> >
> > As Brian Ripley already told you, you are so wrong that it is unclear
why
> we
> > bother helping you for matters clearly stated in manuals you continue
to
> > ignore.
> >
> > Anyway -- on my Debian system, your file compiles, builds and runs
"fine":
> >
> > edd at basebud:/tmp> gcc -o globetrotter -I/usr/share/R/include
globetrotter.c
> > -lm -lRmath -L/usr/lib/R/lib -lR
> > edd at basebud:/tmp> LD_LIBRARY_PATH=/usr/lib/R/lib ./globetrotter
> > 0.040160
> > 0.040160
> >
> > That said, I put "fine" in quotes as you shouldn't need
either -lR nor the
> > include directive. Witness:
> >
> > edd at basebud:/tmp> cp /usr/share/doc/r-mathlib/examples/test.c
nmtest.c
> > edd at basebud:/tmp> gcc -o nmtest nmtest.c -lm -lRmath
> > edd at basebud:/tmp> ./nmtest
> > edd at basebud:/tmp> tail -6 nmtest.c
> > main()
> > {
> > /* something to force the library to be included */
> > qnorm(0.7, 0.0, 1.0, 0, 0);
> > return 0;
> > }
> > edd at basebud:/tmp>
> >
> > The key is the
> > #define MATHLIB_STANDALONE 1
> > in the R example. Once you add that before the #include for Rmath.h,
you're
> > fine:
> > edd at basebud:/tmp> gcc -o globetrotter globetrotter.c -lm -lRmath
> > edd at basebud:/tmp> ./globetrotter
> > 0.040160
> > 0.040160
> > edd at basebud:/tmp> cat globetrotter.c
> > #include<stdio.h>
> > #include<stdlib.h>
> > #define MATHLIB_STANDALONE 1
> > #include <Rmath.h>
> >
> > int main(void) {
> > printf("%f \n",pchisq(2.,7., 1, 0));
> > printf("%f \n",pnchisq(2.,7.,0., 1, 0));
> > return EXIT_SUCCESS;
> > }
> >
> > As they say, if all else fails you could consider reading the manual
that
> > discusses this example.
> >
> > Dirk
> >
> >
> > --
> > Hell, there are no rules here - we're trying to accomplish
something.
> > -- Thomas A. Edison
> >
>
>
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