R help - Jul 2010 - Call to rgamma using .C causes R to hang

Hi,

I've been trying to get this working for ages, but it causes R to hang.

Here is my C code saved as test1.c

# include <R.h>
# include <Rmath.h>
void test1 (double *x, double *result)
{
     result[0] = rgamma(*x, 2.0);
}

This was compiled using R CMD SHLIB test1.c & loaded in R using:

dyn.load("test1.dll")
out <- .C("test1",x=as.double(2),random=double(1))

R then hangs

However, if I change "rgamma" in the above to be "rnorm" or
"runif",
everything works just fine. I'm not sure if it matters, but the function 
'rgamma' under R works OK.

I'm running Windows XP & I followed the instructions at
http://cran.r-project.org/doc/manuals/R-admin.html#Windows-standalone
after building R from source.


Thanks,

Steve

G'day Steve,

On Tue, 20 Jul 2010 17:20:49 +0930
Steve Pederson <stephen.pederson at adelaide.edu.au> wrote:

I suggest to insert the following two lines (untested as I usually
don't work on Windows):
 
> # include <R.h>
> # include <Rmath.h>
> void test1 (double *x, double *result)
> {
	GetRNGstate();
>      result[0] = rgamma(*x, 2.0);
	PutRNGstate();
> }
> 
[...] 
> I'm running Windows XP & I followed the instructions at
> http://cran.r-project.org/doc/manuals/R-admin.html#Windows-standalone
> after building R from source.
But you didn't follow the instructions of Section 6.3 in the "Writing R
Extensions manual. :)

http://cran.r-project.org/doc/manuals/R-exts.html#Random-numbers

HTH.

Cheers,

	Berwin

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