rcpp

问题 [I had this sketched out as a comment elsewhere but decided to create a proper question...] What is currently considered "best practice" in terms of code structuring when using data frames in Rcpp? The ease with which one can "beam over" an input data frame from R to the C++ code is remarkable, but if the data frame has n columns, is the current thinking that this data should be split up into n separate (C++) vectors before being used? The response to my previous question on making use of a

问题 I have been using Rcpp and RInside, to integrate R and C++ . We have a complex, yet well designed C++ architecture, and I am finding it difficult to access R from within just 1 function. Is it possible to pass the R instance to different Classes / functions, to get a more OOP design ? If yes, are there any examples ? To elaborate the query, I want to say that something like this, void foo(RInside& R0, int& x0) { R0.assign(x0,"totalSum"); } void foo2(RInside& R0, int& y0) { R0.assign(y0,"temp"

问题 How can I resize in Rcpp a NumericVector ? When I use the push_back function for this, the Program slows down. But there are no .resize() or .reserve() functions. (When I have already a NumericVector with the desired size, I can use the copy-constructor to get the correct size of the NumericVector . This is in such a case much faster than usage of push_back ) 回答1: If you prefer the C++ idioms, use std::vector<double> and return that at the end where it will be converted via an implicit wrap()

问题 I'm trying to get the inline package working on my macbook. The following block of code (from the cxxfunction examples) fails: library(inline) fx <- cxxfunction( signature(x = "integer", y = "numeric" ) , ' return ScalarReal( INTEGER(x)[0] * REAL(y)[0] ) ; ' ) fx( 2L, 5 ) With this error: Error in compileCode(f, code, language = language, verbose = verbose) : Compilation ERROR, function(s)/method(s) not created! make: g++-4.2: No such file or directory make: *** [file141b5882.o] Error 1 This

问题 I started playing around with Rcpp and would like to use the fastLm function as an example (also because it's useful for potential later work). I know that fastLm is part of the RcppArmadillo package but I would like to compile it using sourceCpp . The code can be found here and is also below. The first problem I encounter is that I can't simply run sourceCpp("fastLm.cpp") in R after installing and loading Rcpp and RcppArmadillo . I get this error error: RcppArmadillo.h: No such file or

问题 I am trying to use some code from OpenCV in an R package, using Rcpp to build the package. When I compile the c code on my machine, it works fine. For example, I am using the the following syntax locally to compile the facedetect.cpp code: g++ `pkg-config --cflags opencv` facedetect.cpp -o facedetect `pkg-config --libs opencv` However, when I try to include it in my package using the following command: R CMD SHLIB facedetect.cpp -o facedetect with the following defined in my makevars file:

问题 I've managed to get the Rcpp.package.skeleton to INSTALL in Windows by the following commands at the R prompt - Rcpp.package.skeleton("mypackage") system("R CMD build mypackage") system("R CMD INSTALL mypackage") library(mypackage) This creates the mypackage.dll . However when I do the following commands - rcpp_hello_world <- function(){ .Call( "rcpp_hello_world", PACKAGE = "mypackage")} rcpp_hello_world() I get the following error: Error in .Call("rcpp_hello_world", PACKAGE = "mypackage") :

问题 We know that calling Rf_error() should be avoided in Rcpp as it involves a longjmp over C++ destructors on the stack. This is why we rather throw C++ exceptions in Rcpp code (like throw Rcpp::exception("...") or via the stop("...") function). However, R warnings may also result in a call to Rf_error() (this behavior depends on the warn option). So, a call to Rf_warning() is also risky. Rcpp::sourceCpp(code = ' #include <Rcpp.h> using namespace Rcpp; class Test { public: Test() { Rcout <<

问题 In R, if we have a data matrix, say a 100 by 10 matrix X, and a 100-elements vector t with possible values (0, 1, 2, 3), we can easily find a submatrix y of X using a simple syntax: y = X[t == 1, ] But, the problem is, how can I do that with Rcpp's NumericMatrix ? (Or, more generally, how can I do that in C++'s any containers ?) Thanks to Dirk's hint, it seems that NumericMatrix X(dataX); IntegerVector T(dataT); mat Xmat(X.begin(), X.nrow(), X.ncol(), false); vec tIdx(T.begin(), T.size(),

问题 I have consulted existing entries on SO related to my specific issue, but still could not resolve it. I am trying to do this with my machine at work, where I have limited admin rights, but I can run Rtools.exe, so I installed it. My setup for R is: platform x86_64-w64-mingw32 arch x86_64 os mingw32 system x86_64, mingw32 version.string R version 3.3.0 (2016-05-03) I am RStudion Version 0.99.902. I installed Rtools version 3.3.0.1959. All of R, Rstudio, and Rtools are installed in C:/WORK/,