On 24 March 2011 at 01:27, nandan amar wrote:
| Hello,
| I tried following code for copying data from an R array to C++ array variable
| ------------------------------------------------------------------
| #include <R.h>
| #include <R_ext/Applic.h>
| #include <Rinternals.h>
| #include <RInside.h>
| int main(int argc, char *argv[])
| {
|
| RInside R(argc, argv);
| float sum[50];//int sum[50];
| R.parseEvalQ("arr<-c(1:50)") ;
| for(int i=0;i<=50;i++)
| sum[i] = R["arr[i]"];
| for(int i=0;i<=50;i++)
| std::cout << "value: " << sum[i] << std::endl ;
| exit(0);
| }
|
-------------------------------------------------------------------------------
| It got compiled and I got following error while running. Error is same for sum
| [] to be int/float
|
| terminate called after throwing an instance of 'Rcpp::not_compatible'
| what(): expecting a single value
| Aborted
You had a couple of small errors in there (indices from 0 to 50) as well as
one design issue: R _and_ C++ (when using STL) know vectors, so why do this
element-wise? Lastly, your 'i' is only known in C++ but not in R so it can
never index.
Below are two different fixed versions, each running just to 5 rather than 50.
Cheers, Dirk
edd@max:~/svn/rinside/pkg/inst/examples/standard$ make
g++ -I/usr/share/R/include -I/usr/local/lib/R/site-library/Rcpp/include
-I"/usr/local/lib/R/site-library/RInside/include" -O3 -pipe -g -Wall
nandan2.cpp -L/usr/lib64/R/lib -lR -lblas -llapack
-L/usr/local/lib/R/site-library/Rcpp/lib -lRcpp
-Wl,-rpath,/usr/local/lib/R/site-library/Rcpp/lib
-L/usr/local/lib/R/site-library/RInside/lib -lRInside
-Wl,-rpath,/usr/local/lib/R/site-library/RInside/lib -o nandan2
g++ -I/usr/share/R/include -I/usr/local/lib/R/site-library/Rcpp/include
-I"/usr/local/lib/R/site-library/RInside/include" -O3 -pipe -g -Wall
nandan.cpp -L/usr/lib64/R/lib -lR -lblas -llapack
-L/usr/local/lib/R/site-library/Rcpp/lib -lRcpp
-Wl,-rpath,/usr/local/lib/R/site-library/Rcpp/lib
-L/usr/local/lib/R/site-library/RInside/lib -lRInside
-Wl,-rpath,/usr/local/lib/R/site-library/RInside/lib -o nandan
edd@max:~/svn/rinside/pkg/inst/examples/standard$ ./nandan; cat nandan.cpp
value: 1
value: 2
value: 3
value: 4
value: 5
// -*- mode: C++; c-indent-level: 4; c-basic-offset: 4; tab-width: 8; -*-
#include <RInside.h>
int main(int argc, char *argv[]) {
RInside R(argc, argv);
float sum[5];//int sum[50];
R.parseEvalQ("arr <- c(1:50)") ;
for(int i=1;i<=5;i++) {
char txt[32];
sprintf(txt, "z <- arr[%d]; z", i);
sum[i-1] = R.parseEval(txt);;
}
for(int i=0;i<5;i++)
std::cout << "value: " << sum[i] << std::endl ;
exit(0);
}
edd@max:~/svn/rinside/pkg/inst/examples/standard$ ./nandan2; cat nandan2.cpp
value: 1
value: 2
value: 3
value: 4
value: 5
// -*- mode: C++; c-indent-level: 4; c-basic-offset: 4; tab-width: 8; -*-
#include <RInside.h>
int main(int argc, char *argv[]) {
RInside R(argc, argv);
float sum[5];//int sum[50];
R.parseEvalQ("arr <- c(1:50)") ;
for(int i=1;i<=5;i++) {
char txt[32];
sprintf(txt, "z <- arr[%d]", i);
R.parseEvalQ(txt);
sum[i-1] = R["z"];
}
for(int i=0;i<5;i++)
std::cout << "value: " << sum[i] << std::endl ;
exit(0);
}
edd@max:~/svn/rinside/pkg/inst/examples/standard$
--
Dirk Eddelbuettel | e...@debian.org | http://dirk.eddelbuettel.com
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