Nate,
The problem here is how you are have implemented your static member of
trackIdx. You only declared it.
I'd suggest one of two alternatives:
// add this below the struct declaration.
int trackIdx::tracker = 0;
Or, just create it in the function where you actually use it instead of
making it a member.
int operator() (std::string x1, std::string x2) {
static int tracker;
tracker++;
return ((s1==x1 && s2==x2) ? (tracker-1) : -1);
}
On Wed, Oct 22, 2014 at 12:39 PM, nate russell <russell.n2...@gmail.com>
wrote:
> Hello,
>
> I am running into the "Error in dyn.load [...] unable to load shared
> object ['/tmp/...'] undefined symbol [_...]" error; however it is only
> happening with one particular Rcpp function, which I find puzzling. Here is
> my .cpp file containing two functions - I can compile the first one without
> any issue (in its own file), but the second brings about the noted error
> message:
>
>
> #include <Rcpp.h>
> #include <vector>
> #include <string>
> #include <algorithm>
> // [[Rcpp::plugins(cpp11)]]
>
> /*
> * Works fine.
> */
>
> struct checkTwo {
> public:
> checkTwo(const std::string& s1_, const std::string& s2_)
> : s1(s1_), s2(s2_) {}
> int operator() (std::string x1, std::string x2) {
> return (s1==x1 && s2==x2 ? 1 : 0);
> }
> private:
> std::string s1;
> std::string s2;
> };
>
> // [[Rcpp::export]]
> int count_if_if(const Rcpp::DataFrame& df,
> const std::string& c1,
> const std::string& c2)
> {
> std::vector<std::string> vc1 = df["C1"];
> std::vector<std::string> vc2 = df["C2"];
> int N = df.nrows();
>
> std::vector<int> vcount;
> vcount.resize( N );
>
>
> std::transform(vc1.begin(),vc1.end(),vc2.begin(),vcount.begin(),checkTwo(c1,c2));
> int total = std::accumulate(vcount.begin(),vcount.end(),0);
>
> return total;
> }
>
> /*
> * Does not compile.
> */
>
> struct trackIdx {
> public:
> trackIdx(const std::string& s1_, const std::string& s2_)
> : s1(s1_),s2(s2_) {}
> int operator() (std::string x1, std::string x2) {
> tracker++;
> return ((s1==x1 && s2==x2) ? (tracker-1) : -1);
> }
> private:
> std::string s1;
> std::string s2;
> static int tracker;
> };
>
> // [[Rcpp::export]]
> std::vector<int> mc_index(const Rcpp::DataFrame& df,
> const std::string& c1,
> const std::string& c2)
> {
> std::vector<std::string> vc1 = df["C1"];
> std::vector<std::string> vc2 = df["C2"];
> int N = df.nrows();
>
> std::vector<int> vcount;
> vcount.resize( N );
>
> std::vector<int> result;
> result.resize( N );
>
>
> std::transform(vc1.begin(),vc1.end(),vc2.begin(),vcount.begin(),trackIdx(c1,c2));
> std::copy_if(vcount.begin(),vcount.end(),result.begin(),
> [](int i) -> bool {
> return !(i<0);
> });
>
> return result;
> }
>
>
> The above functions (only "count_if_if" at the moment) can be tested like
> this:
>
> Df <- data.frame(
> C1=rep(LETTERS[1:4],each=15),
> C2=as.character(rep(rep(1:3,each=5),4)),
> C3=rep(rep(1:3,each=5),4),
> stringsAsFactors=FALSE)
> ##
> count_if_if(Df,"B","3")
> ##
> # mc_index(Df,"B","3")
>
>
>
> The exact error message I am getting is:
>
> Error in
> dyn.load("/tmp/Rtmpw7VSkV/sourcecpp_27046ca49cd4/sourceCpp_67600.so") :
> unable to load shared object
> '/tmp/Rtmpw7VSkV/sourcecpp_27046ca49cd4/sourceCpp_67600.so':
> /tmp/Rtmpw7VSkV/sourcecpp_27046ca49cd4/sourceCpp_67600.so: undefined
> symbol: _ZN8trackIdx7trackerE
>
>
> and judging by the last bit, "undefined symbol: _ZN8trackIdx7trackerE", it
> looks like my "trackIdx" function object is the source of the problem.
>
> I have tested this on two different platforms -
>
> my network server running CentOS 7:
>
> R version 3.1.1
> Platform: x86_64-redhat-linux-gnu (64-bit)
> Rcpp_0.11.3
>
>
> and my laptop running Ubuntu 14.04:
>
> R version 3.0.2
> Platform: x86_64-pc-linux-gnu (64-bit)
> Rcpp_0.11.2
>
>
> Both of these machines use a reasonably up-to-date version of g++ that
> supports c++11 (although I don't think this has anything to do with the
> issue). I have never had any problems compiling Rcpp functions on either of
> these platforms, yet the second function object & Rcpp function above
> produce the same error on each machine. If anyone can explain what is going
> wrong and/or suggest how to correct the problem with the above code I would
> appreciate it very much.
>
> Thank you,
> Nathan Russell
>
>
>
>
>
>
> _______________________________________________
> Rcpp-devel mailing list
> Rcpp-devel@lists.r-forge.r-project.org
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>
--
-------------------------
Matt Wright
312-264-2987 (p)
312-479-6821 (m)
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