[Rd] Problem with R math library.

[Guillaume Yziquel]

Guillaume Yziquel a écrit :
> Dirk Eddelbuettel a écrit :
>>
>> Salut Guilluame,
>>
>> | > val norm_rand : unit -> float
>> | > Random variates from the standard normal distribution. Bug: 
>> currently systematically returns -8.77332116900134373.
>> | | Any idea as to why the function systematically returns the same 
>> value? | Is there a way the math library should be initialised?
>>
>> I think it is pretty clearly documented in R-exts:
>>
>>   However, before these are used, the user must call
>>          GetRNGstate();
>>     and after all the required variates have been generated, call
>>          PutRNGstate();
>>     These essentially read in (or create) `.Random.seed' and write it out
>>   after use.
> 
> Fair enough. I admit I've been busy with low detail stuff, and omitted 
> to come back to R-exts.
> 
> However, I have another question on which I do not find information (I 
> found it once, but do not know how to find it again...): What's the big 
> difference between using the R mathematical library in standalone mode 
> and not in standalone mode? How does it translate in terms of C 
> directives and linking modalities? I've noticed the MATHLIB_STANDALONE 
> macro, but I do not know how I should use it...
> 
> All the best,

OK. So concerning the headers:

#define MATHLIB_STANDALONE
#include <Rmath.h>

Concerning dependencies: compile against only libRmath.so. Not against 
libR.so. (I wonder why this is so crucial, though...)

Concerning documentation: Section 9 The standalone Rmath library from 
the R-admin.pdf documentation.

This solved my problem, since I'm able to generated random values with 
norm_rand, unif_rand, etc...

Thank you for your help.

-- 
      Guillaume Yziquel
http://yziquel.homelinux.org/