[R] rgamma function
zuo at stat.wisc.edu
Mon Jul 16 21:49:24 CEST 2012
Sorry that I posted the wrong syntax. My initial program is very long
and I tried to post the section where I have been narrowed to locate the
In this sample I am simulating a Gamma with size parameter 5000 and
scale parameter 1.
I plugged in many breaks in my initial program and what I found was that
most of the time the program stops when encountering a call to rgamma()
function. It just freezes without popping out any error.
SEXP generateGamma ()
Thanks for your suggestions!
On 07/15/12 07:07, peter dalgaard wrote:
> On Jul 14, 2012, at 04:55 , Chandler Zuo wrote:
>> Has anyone encountered the problem of rgamma function in C? The following simplified program always dies for me, and I wonder if anyone can tell me the reason.
>> SEXP generateGamma ()
>> return (rgamma(5000,1));
>> Has anyone encountered a similar problem before? Is there another way of generating Gamma random variable in C?
>> P.S. I have no problem compiling and loading this function in R.
> It doesn't even give off a warning??
> The prototype in Rmath.h is
> double rgamma(double, double);
> and you should be returning an SEXP. As soon as something tries to interpret the double value as a pointer -- Poof!
> Notice that rgamma in C is not the same function as the R counterpart, in particular it isn't vectorized, so only generates one random number at a time. The long and the short of it is that you need to read up on sections 5.9 and 5.10 of Writing R Extensions.
>> Thanks for suggestions in advance!
>> R-help at r-project.org mailing list
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
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