[Rcpp-devel] Eigen-like pointer mappings in Rcpp?

[Sparapani, Rodney]

Hi Gang:

I am working with some C++ code that uses pointers.  I know I could 
change the code.  But, I was wondering if there is an easy way to
map the double pointer into the R data via Rcpp.  I have been using 
RcppEigen to do that.  For example...

RcppExport SEXP myfunc(SEXP _n, SEXP _x) {
   const int n=Rcpp::as<int>(_n);

   double *x=(double *)malloc(n*sizeof(double));

   Eigen::Map<Eigen::VectorXd> map_x(x, n);

   map_x=Rcpp::as< Eigen::Map<Eigen::VectorXd> >(_x);

   double a=fit(x, n);

...

It seems to me there should be an easier way like ...

RcppExport SEXP myfunc(SEXP _n, SEXP _x) {
   const int n=Rcpp::as<int>(_n);

   double *x=Rcpp::as<double*>(_x); // or a const-correct version

   double a=fit(x, n);

...

Thanks,

Rodney