Message-ID: <4B618A52.6080805@citycable.ch>
Date: 2010-01-28T13:00:02Z
From: Guillaume Yziquel
Subject: Problem with R math library.
In-Reply-To: <19297.33736.990250.454097@ron.nulle.part>
Dirk Eddelbuettel a ?crit :
>
> 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,
--
Guillaume Yziquel
http://yziquel.homelinux.org/