On 1 March 2016 at 10:29, Philippe Huber wrote:
| Hi,
|
| I am starting to use Rcpp and got into some issues with basic examples.
|
| I am trying to run this:
|
| #include <Rcpp.h>
|
| using namespace Rcpp;
|
| // [[Rcpp::export]]
| NumericVector timesTwo(NumericVector x) {
| return x * 2;
| }
|
| It works fine when I use it like:
| > evalCpp(timesTwo(2))
| [1] 4
|
| But as soon as I use a vector, I get some weird error message:
|
| > v=as.vector(c(2,2))
| > evalCpp(timesTwo(v))
| g++ -m64 -I"C:/PROGRA~1/R/R-32~1.3/include" -DNDEBUG -I"C:/Users/Hubert/
| Documents/R/win-library/3.2/Rcpp/include"
-I"C:/Users/Hubert/AppData/Local/Temp
| /RtmpaujML3" -I"d:/RCompile/r-compiling/local/local323/include" -O2 -Wall
| -mtune=core2 -c file33c329d4fd2.cpp -o file33c329d4fd2.o
| file33c329d4fd2.cpp: In function 'SEXPREC* get_value()':
| file33c329d4fd2.cpp:7:6: error: redefinition of 'SEXPREC* get_value()'
| file33c329d4fd2.cpp:6:6: error: 'SEXPREC* get_value()' previously defined here
| make: *** [file33c329d4fd2.o] Error 1
| Warning message:
| l'exécution de la commande 'make -f "C:/PROGRA~1/R/R-32~1.3/etc/x64/Makeconf"
| -f "C:/PROGRA~1/R/R-32~1.3/share/make/winshlib.mk" SHLIB_LDFLAGS='$
| (SHLIB_CXXLDFLAGS)' SHLIB_LD='$(SHLIB_CXXLD)' SHLIB="sourceCpp_10.dll" WIN=64
| TCLBIN=64 OBJECTS="file33c329d4fd2.o"' renvoie un statut 2
| Error in sourceCpp(code = code, env = env, rebuild = rebuild, showOutput =
| showOutput, :
| Error 1 occurred building shared library.
|
| I tried to find a solution but got nothing.
|
| Can someone please help me?
help(evalCpp) tells you "Evaluates a C++ expression" which is correct. The
canonical example is something like
evalCpp("2 + 2")
What you want here is sourceCpp() to source and run a file. Please see the
vignette 'Rcpp Attribute' for countless examples. You can, as in the
augmented example below, even include R code to be run after the build:
R> sourceCpp("/tmp/sourceCppEx.cpp")
R> timesTwo(21)
[1] 42
R> timesTwo(c(1,3,5))
[1] 2 6 10
R>
As you can see, works as expected.
Dirk
------------- example with included R snippet below -------------------------
#include <Rcpp.h>
using namespace Rcpp;
// [[Rcpp::export]]
NumericVector timesTwo(NumericVector x) {
return x * 2;
}
/***R
timesTwo(21)
timesTwo(c(1,3,5))
*/
-----------------------------------------------------------------------------
--
http://dirk.eddelbuettel.com | @eddelbuettel | e...@debian.org
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