<div dir="ltr">Just for the sake of completeness, I noticed that the value of trackIdx::tracker was persisting (and therefore continuing to be incremented) between function calls with mc_index, so in addition to your first suggestion, I added a member function to reset the value to zero, and everything seems to be working smoothly. Once again, thank you for your help. <br><br>Nathan Russell<br><br><br><br><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div>#include <Rcpp.h></div><div>#include <vector></div><div>#include <string></div><div>#include <algorithm></div><div>// [[Rcpp::plugins(cpp11)]]</div><div><br></div><div>class trackIdx {</div><div> public:</div><div> trackIdx(const std::string& s1_, const std::string& s2_)</div><div> : s1(s1_),s2(s2_) {}</div><div> int operator() (std::string x1, std::string x2) {</div><div> tracker++;</div><div> return (s1==x1 && s2==x2 ? (tracker-1) : -10);</div><div> }</div><div> void reset() { tracker = 0; }</div><div> private:</div><div> std::string s1;</div><div> std::string s2;</div><div> static int tracker;</div><div>};</div><div><br></div><div>int trackIdx::tracker = 0;</div><div><br></div><div>// [[Rcpp::export]]</div><div>std::vector<int> mc_index(const Rcpp::DataFrame& df,</div><div> const std::string& c1,</div><div> const std::string& c2)</div><div>{</div><div> std::vector<std::string> vc1 = df["C1"];</div><div> std::vector<std::string> vc2 = df["C2"];</div><div> int N = df.nrows();</div><div> </div><div> std::vector<int> vcount;</div><div> vcount.resize( N );</div><div> </div><div> trackIdx track(c1,c2);</div><div> </div><div> std::transform(vc1.begin(),vc1.end(),vc2.begin(),vcount.begin(),track);</div><div> vcount.erase(</div><div> std::remove_if(vcount.begin(),vcount.end(),</div><div> [](int i) -> bool {</div><div> return (i<0);</div><div> }),</div><div> vcount.end());</div><div> </div><div> track.reset();</div><div> return vcount;</div><div>}</div></blockquote><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Oct 22, 2014 at 2:29 PM, nate russell <span dir="ltr"><<a href="mailto:russell.n2012@gmail.com" target="_blank">russell.n2012@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Matthew, <br><br>Thank you for such a quick response; both of those suggestions worked perfectly. Out of curiosity, is there any reason to use one of these implementations over the other - or are they essentially equivalent? <br><br>Regards,<br>Nathan Russell</div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Oct 22, 2014 at 2:10 PM, Matthew Wright <span dir="ltr"><<a href="mailto:mattw@trdlnk.com" target="_blank">mattw@trdlnk.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Nate,<div><br>The problem here is how you are have implemented your static member of trackIdx. You only declared it.</div><div><br></div><div>I'd suggest one of two alternatives:</div><div><div><br></div><div>// add this below the struct declaration.</div><div>int trackIdx::tracker = 0;</div></div><div><br></div><div>Or, just create it in the function where you actually use it instead of making it a member.</div><div><span><div> int operator() (std::string x1, std::string x2) {</div></span><div> static int tracker;</div><span><div> tracker++;</div><div> return ((s1==x1 && s2==x2) ? (tracker-1) : -1);</div><div> }</div></span></div><div><br></div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div>On Wed, Oct 22, 2014 at 12:39 PM, nate russell <span dir="ltr"><<a href="mailto:russell.n2012@gmail.com" target="_blank">russell.n2012@gmail.com</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div><div dir="ltr">Hello,<br><br>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:<br><br><br><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div>#include <Rcpp.h></div><div>#include <vector></div><div>#include <string></div><div>#include <algorithm></div><div>// [[Rcpp::plugins(cpp11)]]</div><div><br></div><div>/*</div><div> * Works fine. </div><div> */</div><div><br></div><div>struct checkTwo {</div><div> public:</div><div> checkTwo(const std::string& s1_, const std::string& s2_)</div><div> : s1(s1_), s2(s2_) {}</div><div> int operator() (std::string x1, std::string x2) {</div><div> return (s1==x1 && s2==x2 ? 1 : 0);</div><div> }</div><div> private:</div><div> std::string s1;</div><div> std::string s2;</div><div>};</div><div><br></div><div>// [[Rcpp::export]]</div><div>int count_if_if(const Rcpp::DataFrame& df,</div><div> const std::string& c1,</div><div> const std::string& c2)</div><div>{</div><div> std::vector<std::string> vc1 = df["C1"];</div><div> std::vector<std::string> vc2 = df["C2"];</div><div> int N = df.nrows();</div><div> </div><div> std::vector<int> vcount;</div><div> vcount.resize( N );</div><div> </div><div> std::transform(vc1.begin(),vc1.end(),vc2.begin(),vcount.begin(),checkTwo(c1,c2));</div><div> int total = std::accumulate(vcount.begin(),vcount.end(),0);</div><div> </div><div> return total;</div><div>}</div><div><br></div><div>/*</div><div> * Does not compile. </div><div> */</div><div><br></div><div>struct trackIdx {</div><div> public:</div><div> trackIdx(const std::string& s1_, const std::string& s2_)</div><div> : s1(s1_),s2(s2_) {}</div><div> int operator() (std::string x1, std::string x2) {</div><div> tracker++;</div><div> return ((s1==x1 && s2==x2) ? (tracker-1) : -1);</div><div> }</div><div> private:</div><div> std::string s1;</div><div> std::string s2;</div><div> static int tracker;</div><div>};</div><div><br></div><div>// [[Rcpp::export]]</div><div>std::vector<int> mc_index(const Rcpp::DataFrame& df,</div><div> const std::string& c1,</div><div> const std::string& c2)</div><div>{</div><div> std::vector<std::string> vc1 = df["C1"];</div><div> std::vector<std::string> vc2 = df["C2"];</div><div> int N = df.nrows();</div><div> </div><div> std::vector<int> vcount;</div><div> vcount.resize( N );</div><div> </div><div> std::vector<int> result;</div><div> result.resize( N );</div><div> </div><div> std::transform(vc1.begin(),vc1.end(),vc2.begin(),vcount.begin(),trackIdx(c1,c2));</div><div> std::copy_if(vcount.begin(),vcount.end(),result.begin(),</div><div> [](int i) -> bool {</div><div> return !(i<0);</div><div> });</div><div> </div><div> return result;</div><div>}</div></blockquote><div><br>The above functions (only "count_if_if" at the moment) can be tested like this:<br><br></div><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div>Df <- data.frame(</div></div><div><div> C1=rep(LETTERS[1:4],each=15),</div></div><div><div> C2=as.character(rep(rep(1:3,each=5),4)),</div></div><div><div> C3=rep(rep(1:3,each=5),4),</div></div><div><div> stringsAsFactors=FALSE)</div></div><div><div>##</div></div><div><div>count_if_if(Df,"B","3")</div></div><div><div>##</div></div><div><div># mc_index(Df,"B","3")</div></div></blockquote><div><br><br>The exact error message I am getting is:<br><br></div><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px"><div><div>Error in dyn.load("/tmp/Rtmpw7VSkV/sourcecpp_27046ca49cd4/sourceCpp_67600.so") : </div></div><div><div> unable to load shared object '/tmp/Rtmpw7VSkV/sourcecpp_27046ca49cd4/sourceCpp_67600.so':</div></div><div><div> /tmp/Rtmpw7VSkV/sourcecpp_27046ca49cd4/sourceCpp_67600.so: undefined symbol: _ZN8trackIdx7trackerE</div></div></blockquote><div><br>and judging by the last bit, "undefined symbol: _ZN8trackIdx7trackerE", it looks like my "trackIdx" function object is the source of the problem. <br><br>I have tested this on two different platforms - <br><br>my network server running CentOS 7:<br><br></div><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px">R version 3.1.1 <br>Platform: x86_64-redhat-linux-gnu (64-bit)<br>Rcpp_0.11.3</blockquote><br>and my laptop running Ubuntu 14.04:<br><br><blockquote style="margin:0px 0px 0px 40px;border:none;padding:0px">R version 3.0.2<br>Platform: x86_64-pc-linux-gnu (64-bit)<br>Rcpp_0.11.2</blockquote><br>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. <br><br>Thank you,<br>Nathan Russell<br><br><br><br><br><br></div>
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