Le 23/10/2013 06:12, [email protected] a écrit :
Hi,
This has to be a basic question, but I cannot figure out what I am missing nor
see quite similar pre-existing posts.
I am trying to create an Rcpp module around a class (generated C++ proxy
class). The environment is Rcpp 0.10.5 on Windows, R 3.0.2 x64 and RTools 3.0.
R CMD INSTALL spits the dummy at compilation(?) time when the Exporter things kick in, with the
message " cannot convert 'SEXP' to 'const std::vector<double>*' in
initialization" on the 'Play' method as per below.
class SimulationExport {
public:
SimulationExport();
~SimulationExport();
void Execute(void);
void Play(const char* name, const std::vector<double>* values);
// other methods snipped
}
RCPP_MODULE(SimulationEx){
class_<SimulationExport>( "Simulation" )
// snipped
.method( "play", &SimulationExport::Play)
// snipped
}
I don't get why it cannot wrap a vector<double> given how similar it is to "7.2.2.7 Full
Example" in the " Seamless R and C++ Integration with Rcpp" book. The same sample code
created with Rcpp.package.skeleton compiles (though it fails check on load, BTW). The only difference is
the presence of a 'const' modifier before the vector, but removing it does not solve the issue.
Rcpp.package.skeleton('sampleRcpp', module=TRUE, author='J-M')
library(devtools)
check('sampleRcpp') # passes past the compilation step.
Cheers,
J-M
As Dirk said, don't use a pointer to a std::vector<double>.
What do you do in Play with this vector ?
Why did you want to pass it as a pointer ? If this was for performance,
then passing a reference won't cut it because Rcpp cheats and when you
pass a reference as a parameter to a function that is Rcpp::export'ed,
what happens is that the data gets copied.
Could you instead pass down an NumericVector ? The reason is that given
Rcpp's design, copy semantics of NumericVector are cheap (no data copy).
Which leads back to hte original question: what does Play want to do
with this vector ?
Romain
--
Romain Francois
Professional R Enthusiast
+33(0) 6 28 91 30 30
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