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C++ with R on Mac OS

It sometimes could be a great idea to incorporate bits of C++ into our R coding through the Rcpp package. Before writing or calling our C++ functions, we need firstly a working C++ setup for R, which is not difficult on Mac OS system.

First, we need a C++ compiler. We can download XCode and install the Command Line Tools. Second, we need to create a file $\sim$/.R/Makevars, to tell R which compliers to use. The file creation can be done by typing the following commands in Terminal,

cd ~/.R
nano Makevars

Now add the following text:

CC = clang
CXX = clang++

And follow the directions at the bottom of the screen to "write out" and close the file (Control-O Enter and Control-X). Next, we need to install Rcpp package in R from source so that it is built with the same C++ complier we are using.

install.packages("Rcpp", type = "source")

After finishing the setup of connection between C++ and R, we can write a C++ function that R can call. This C++ file should have extension .cpp. And we can thus source it into R using sourceCpp(). It will create a matching R function and we can use it with input.
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