Romain, Thanks a lot for the clarifications!
Anwar On Jun 29, 2013, at 12:35 PM, Romain Francois <rom...@r-enthusiasts.com> wrote: > Hello, > > just use: > > double* values = input.begin() ; > > A NumericVector uses R allocated memory, and R allocates an array of doubles > to store a numeric vector. > > You then need to remember you dońt own the pointer. So make sure your code > does not eg delete[] it. > > The code you've used was very inefficient and will make many unecessary > copies of the data, each time the std::vctor wants to grow. > > If you want a std:vector you can do something like this: > > std::vector<double> vec( input.begin(), input.end() ) ; > > Or: > > std::vector<double> vec = as< std::vector<double> >(input) ; > > Romain > > Le 29 juin 2013 à 12:08, Anwar Ludin <anwar.lu...@riskcetera.com> a écrit : > >> Hello, >> >> I need to interface some R code with a numerical library containing >> functions taking as input double* >> >> What is the most efficient way to create an array of doubles from a >> NumericVector. >> >> I was thinking of something like: >> >> >> >> >> >> >> // input is of type Rcpp::NumericVector and passed from R >> std::vector<double> vec; >> std::copy(input.begin(), input.end(), std::back_inserter(vec)); >> >> double* values = &vec[0]; >> >> // now call function taking a double* >> >> >> Regards, >> >> Anwar >> _______________________________________________ >> 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
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