I need to call R functions through a C++ subroutine. The problem is
that, as many have pointed out, you can't call the RInside environment
more than once. So how do I get my subroutine to "know" about R? Can I
pass something along? I am not really a C++ programmer, so I apologize
for my ignorance. (and THANKS for developing some pretty amazing tools)
Here is an example of what doesn't work.
First, the subroutine:
#include "r_funcs.h"
std::vector< double > ks_test(std::vector< double >x, std::vector<
double >y, int argc, char *argv[]) {
SEXP ans;
R.RInside::assign(x,"x");
R.RInside::assign(y, "y");
std::string evalstr = " \
cat('Running ls()\n'); print(ls()); \
ks <- ks.test(x,y); \
ks$p";
R.RInside::parseEval(evalstr, ans);
RcppVector<double> vec(ans);
std::vector<double> v = vec.stlVector();
return(v);
}
header file:
#ifndef R_FUNCS_H
#define R_FUNCS_H
#include <RInside.h>
//#include <Rcpp.h>
std::vector< double > ks_test(std::vector< double >x, std::vector<
double >y, int argc, char *argv[]);
#endif //R_FUNCS_H
the main file:
#include <stdio.h>
#include "r_funcs.h"
int main(int argc, char *argv[]) {
RInside::RInside R(argc,argv);
// testing stuff
std::vector< double > x(5);
std::vector< double > y(5);
int i;
double var[5] = {1,2.2,3.4,4.33,42.4};
for(i=0; i<5; i++) {
x[i] = var[i];
std::cout << x[i] << std::endl;
}
double var2[5] = {3.224,4.1,4.22,4,4.4};
for(i=0; i<5; i++) {
y[i] = var2[i];
}
// correct function call
std::vector< double > v = ks_test(x,y,argc,argv);
// output
std::cout << "In main_stat_compare, ks p-value is " << v[0] << std::endl;
exit(0);
}
Of course if I move the RInside declaration into the subroutine, this
example works, but I can only call the ks test once. :(
--
----------------------------------------
Eileen Meyer
Physics& Astronomy MS-108
Rice University
6100 Main St. Houston, TX 77005
www.interfolio.com/portfolio/eileenmeyer
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