Hi there, I am trying to write a c++ shared library for R. I need a function which has the same functionality as sample() in R, i.e., does permutation, sample with/without replacement. Does R have internal sample routine so that I can call it directly? I did not find it in R.h, Rinternal.h. Thanks
where is internal function of sample()?
4 messages · Weijie Cai, Marc Schwartz, Brian Ripley +1 more
On Mon, 2005-04-11 at 23:04 -0400, Weijie Cai wrote:
Hi there, I am trying to write a c++ shared library for R. I need a function which has the same functionality as sample() in R, i.e., does permutation, sample with/without replacement. Does R have internal sample routine so that I can call it directly? I did not find it in R.h, Rinternal.h. Thanks
A quick grep of the source code tree tells you that the function is in .../src/main/random.c A general pattern for C .Internal functions is to use a prefix of "do_" in conjunction with the R function name. So in this case, the C function is called do_sample and begins at line 391 (for 2.0.1 patched) in the aforementioned C source file. HTH, Marc Schwartz
On Mon, 11 Apr 2005, Weijie Cai wrote:
I am trying to write a c++ shared library for R. I need a function which has the same functionality as sample() in R, i.e., does permutation, sample with/without replacement. Does R have internal sample routine so that I can call it directly? I did not find it in R.h, Rinternal.h.
That's because it is not in the API. The function is do_sample in src/main/random.c. You could construct an appropriate call with some ingenuity. Please note that R-devel is the list for C-level programming questions, as the posting guide points out.
Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595
On Mon, 11 Apr 2005, Marc Schwartz wrote:
A general pattern for C .Internal functions is to use a prefix of "do_" in conjunction with the R function name. So in this case, the C function is called do_sample and begins at line 391 (for 2.0.1 patched) in the aforementioned C source file.
and in the case of the few exceptions to this rule you can look in names.c for a complete table. -thomas