RcppZiggurat unable to compile example code - r

Question

I am trying to employ the Ziggurat sampler in R, however actually wanted to use it directly in my C++ code. I installed the GSL library, RcppGSL and RcppZiggurat and using zrnorm() in R works just fine. I thought ok, lets try to compile the code sample provided in the RcppZiggurat.pdf, and go from there to implement the Ziggurat sampler directly in my C++ code... the following happens though...
From the pdf file I thought I can simply utilize:
#include <Rcpp.h>
#include <Ziggurat.h>
static Ziggurat::Ziggurat::Ziggurat zigg;
// [[Rcpp::export]]
Rcpp::NumericVector zrnorm(int n) {
Rcpp::NumericVector x(n);
for (int i=0; i<n; i++) {
x[i] = zigg.norm();
}
return x;
}
// [[Rcpp::export]]
void zsetseed(unsigned long int s) {
zigg.setSeed(s);
return;
}
Error:
official_zigg_code.cpp:2:10: fatal error: 'Ziggurat.h' file not found
#include <Ziggurat.h>
^
1 error generated.
make: *** [official_zigg_code.o] Error 1
clang++ -I/Library/Frameworks/R.framework/Resources/include -DNDEBUG -I/usr/local/include -
I/usr/local/include/freetype2 -I/opt/X11/include -
I"/Library/Frameworks/R.framework/Versions/3.1/Resources/library/Rcpp/include" -fPIC -Wall -
mtune=core2 -g -O2 -c official_zigg_code.cpp -o official_zigg_code.o
Error in Rcpp::sourceCpp("official_zigg_code.cpp") :
Error 1 occurred building shared library.
I have absolutely no clue how to proceed from here. I desperately tried to find answers on stack exchange but nothing could help me to solve this. From what I understand the RcppZiggurat package actually uses the above function so how can I fail to compile it, when I am able to use zrnorm() directly?

Answer 1

The error is fairly obvious:
fatal error: 'Ziggurat.h' file not found
This means that you did not tell R / the compiler about RcppZiggurat.
The fix is easy. In the case of an Rcpp-driven compilation via sourceCpp(), add
this one line
// [[Rcpp::depends(RcppZiggurat)]]
which does just that. All this is documented with Rcpp, and you are more or less expected to read at least some of its documentation.
If you want to build outside of Rcpp, you need to make sure the compiler find the header file(s). One commonly uses the -I flag for that, this is typically discussed where compiler are introduced.