[Rcpp-devel] Irregular crash with rcpp and inline

Marie Auger-Methe marie.augermethe at gmail.com
Fri Apr 13 12:31:29 CEST 2012


I am new to Rcpp, c++, and inline. I have created a simple test function 
which works some of the times but not all the times. It generally 
crashes when I run it with a large sample size or after calling the 
function multiple times. When it doesn't work, it crashes R completely 
and so I have no error message that can help me figure out what caused 
the problem.
Here is my code:


     mycppfx <- '
       #include <cmath>

       // Input values
       NumericVector distc(dist);
       NumericVector rtac(rta);
       int nc = distc.size();
       NumericVector dx(nc);
       NumericVector dy(nc);
       NumericMatrix coord(nc+1,2);

       // Transforming relative turning angle into absolute turning angle
       NumericVector ata(nc);
       ata[0] = fmod(rtac[0],2*PI);
       for(int j = 1; j < nc+1; j++){
         ata[j] = fmod(ata[j-1] + rtac[j],2*PI);

       //Change into cartesian coordinates

       // Calculate the displacement in each direction

       dx = distc * cos(ata);
       dy = distc * sin(ata);

       nc += 1;

       // Add the displacments
       for(int j = 1; j < nc; j++){
         coord(j,0) = coord(j-1, 0) + dx[j-1];
         coord(j,1) = coord(j-1, 1) + dy[j-1];

       return coord;
     myfx <- cxxfunction(signature(dist ="NumericVector", 
                       body = mycppfx, plugin = "Rcpp")

     n <- 1000
     dist <- rexp(n,10)
     rta <- rvm(n,0,1)

     res <- myfx(dist,rta)

Any tips would be appreciated,


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