On Wed, Jun 24, 2015 at 11:08 AM, Charles Determan
<cdeterma...@gmail.com> wrote:
> Many thanks Krzysztof, your suggestion works. I can explicitly create a
> 'new' arma::mat object and pass the resulting XPtr between functions. I
> will work on making everything prettier and document for a submission to
> Rcpp Gallery unless someone is aware of one that already exists that I
> somehow overlooked.
>
> // [[Rcpp::export]]
> SEXP testXptr(NumericMatrix A)
> {
> arma::mat *armaMat = new arma::mat(A.begin(),A.rows(), A.cols(), false);
> XPtr<arma::mat> pMat(armaMat);
> return(pMat);
> }
>
> // [[Rcpp::export]]
> void testReturn(SEXP ptrA, int nr, int nc)
> {
> XPtr<arma::mat> ptrB(ptrA);
> arma::mat B = arma::mat( (double *) ptrB->memptr(),
> nr,
> nc,
> false);
> B.print("copied matrix");
> }
You can make this a little nicer:
// [[Rcpp::export]]
void testReturn(XPtr<arma::mat> ptrA, int nr, int nc)
{
arma::mat B = arma::mat( (double *) ptrA->memptr(),
nr,
nc,
false);
B.print("copied matrix");
}
Hadley
--
http://had.co.nz/
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