Le 08/11/2019 à 11:06, LEVRA-JUILLET William a écrit :
Hi all,
I’m evaluating RInside/Rcpp to interact our C++ project with R.
I’ve seen the samples to get/set data (matrix, dataframes, etc) to/from
R and it builds/works fine.
(Using gcc/mingw compiler from RTools on Windows)
My questions is about functions…
My project is C++, and it uses RInside to call R from our code.
Let’s say I have a C++ function implemented in my project, and I want to
pass that c++ function to R so it can be “used” as a R function
(typically passed as argument to optim/optimize)
I couldn’t find a way to do that using RInside.
Ideally, I’d like to achieve something like:
#include <RInside.h>
double Banana(double x, double y)
{
return (1-x)*(1-x)+100*(y-x*x)*(y-x*x);
}
Int main()
{
RInside R(argc,, argv);
R[“fn”] = Banana;
R.parseEval(“optim(c(-2,-2), fn”);
}
I believe it’s similar to
https://stackoverflow.com/questions/53729493/rinside-wrapping-a-c-function-for-use-in-an-r-function
But I can’t really understand the Rcpp::XPtr suggestion from Dirk.
Any help or pointers welcome J
Sorry for a late comment but for what it's worth, XPtr won't help here
as optim() expects an R function, not C++ pointer to a function.
Moreover, this R function takes only one argument -- a vector, not a
couple of scalars. So maybe you meant something similar to:
#include <RInside.h>
int main(int argc, char *argv[]) {
RInside R(argc, argv);
R.parseEval("Rcpp::cppFunction('double Banana(double x, double y)
{return (1-x)*(1-x)+100*(y-x*x)*(y-x*x);};', cacheDir='lib')");
R.parseEval("fn <- function(p, ...) Banana(p[1L], p[2L])");
Rcpp::RObject res = R.parseEval("optim(c(-2,-2), fn)");
Rf_PrintValue(res);
return 0;
}
which prints:
$par
[1] 0.9990277 0.9977136
$value
[1] 1.269722e-05
$counts
function gradient
157 NA
$convergence
[1] 0
$message
NULL
As already underlined by others this is a sub-optimal way to use C++
functions in R but here it is imposed by optim() interface. For better
designed interfaces (at least from "optimality of R/C++ exchanges" point
of view) refer to examples cited by Dirk and Inaki.
Best,
Serguei.
Thx a mil
mailbox:///home/sokol/.thunderbird/r8hre4b3.default/Mail/pop.insa-tlse.fr/Inbox?number=44&header=quotebody&part=1.1.2&filename=image005.jpg
<https://addactis.letsignit.com/r/32/6de77c22-c065-4906-899e-eec38189d60a/undefined>
mailbox:///home/sokol/.thunderbird/r8hre4b3.default/Mail/pop.insa-tlse.fr/Inbox?number=44&header=quotebody&part=1.1.3&filename=image006.png
<https://addactis.letsignit.com/r/199/c042c4a7-2508-4bf6-801a-4eeb09778ade/undefined>
mailbox:///home/sokol/.thunderbird/r8hre4b3.default/Mail/pop.insa-tlse.fr/Inbox?number=44&header=quotebody&part=1.1.4&filename=image007.png
<https://addactis.letsignit.com/r/42/b8791eba-0dab-4aa1-ab9d-813a5f8be48d/undefined>
mailbox:///home/sokol/.thunderbird/r8hre4b3.default/Mail/pop.insa-tlse.fr/Inbox?number=44&header=quotebody&part=1.1.5&filename=image008.png
<https://addactis.letsignit.com/r/45/15ea361f-f441-4b13-94a0-4bdb30820d9a/undefined>
* William **LEVRA-JUILLET*
Senior Software Architect
* ADDACTIS Software*
+33 (0)4 81 92 13 00
www.addactis.com
<https://addactis.letsignit.com/r/32/91871b88-8586-4561-b012-50a3a792527a/undefined>
<https://addactis.letsignit.com/r/32/cf8ac9eb-d46f-4524-bc9e-5cdb532bef11/undefined>
<https://addactis.letsignit.com/r/199/49e483e9-091d-4caf-a1b4-7e37d9c9ac9e/undefined>
<https://addactis.letsignit.com/r/42/72f7499f-cd02-4bd4-835a-88f1053cabf2/undefined>
<https://addactis.letsignit.com/r/45/b9ce1c50-1455-48cb-b90f-b8348d799476/undefined>
* William **LEVRA-JUILLET*
Senior Software Architect
* ADDACTIS Software*
+33 (0)4 81 92 13 00
www.addactis.com
<https://addactis.letsignit.com/r/32/9cd210c2-e7cd-4d30-995a-e3ba4da16780/undefined>
_______________________________________________
Rcpp-devel mailing list
Rcpp-devel@lists.r-forge.r-project.org
https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
_______________________________________________
Rcpp-devel mailing list
Rcpp-devel@lists.r-forge.r-project.org
https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
