[Rcpp-devel] moving lists between functions in a package

[Scott Monroe]

Thanks so much.  Sorry for the silly error in the example.  The following
works, and has the basic functionality I'm looking for.

#include <RcppArmadillo.h>
using namespace Rcpp ;
// [[Rcpp::depends(RcppArmadillo)]]

// [[Rcpp::export]]
List check_B(arma::mat B) {
  int p = B.n_cols;
  arma::mat BB = B*B;
  arma::vec X = B.col(0);

  return Rcpp::List::create(Rcpp::Named("X")=X, Rcpp::Named("BB")=BB,
Rcpp::Named("p")=p);
}

// [[Rcpp::export]]
List check_A(NumericMatrix A) {
  arma::mat B = Rcpp::as<arma::mat>(A);
  Rcpp::List L = check_B(B);
  arma::mat CC = L["BB"];

  return Rcpp::List::create(Rcpp::Named("B")=B, Rcpp::Named("CC")=CC);
}


On Fri, Dec 27, 2013 at 12:51 PM, Dirk Eddelbuettel <edd at debian.org> wrote:

>
> On 27 December 2013 at 12:36, Scott Monroe wrote:
> | I am trying to figure out how to create a package where I have one
> function
> | call another, which returns a list.  Some example .cpp code is below.
>  If I
> | just compile the first function, everything is fine.  When I add the
> second
> | function, I get errors.  I'm sure I'm using the Rcpp::List syntax
> incorrectly,
> | but I haven't had luck finding an example of how to do this.
> |
> | Again, I'd like to be able to call the first function from the second,
> grab the
> | results from the returned list, and do further computations.
> |
> | Thanks, Scott
> |
> |
> | #include <RcppArmadillo.h>
> | using namespace Rcpp ;
> | // [[Rcpp::depends(RcppArmadillo)]]
> |
> | // [[Rcpp::export]]
> | List check_C(NumericMatrix B) {
> |   arma::mat A = Rcpp::as<arma::mat>(B);
> |   int p = A.n_cols;
> |   arma::mat AA = A*A;
> |   arma::vec X = A.col(0);
> |
> |   return Rcpp::List::create(Rcpp::Named("X")=X, Rcpp::Named("AA")=A,
> | Rcpp::Named("p")=p);
> | }
> |
> | // [[Rcpp::export]]
> | List check_C(NumericMatrix A) {
> |   Rcpp::List L = check_C(A);
>
> A comes in as a matrix, now you are trying to make it a List -- that won't.
>
> Plus, as Simon, observed you may want to rename the functions a little.
>
> Dirk
>
> |
> |   return Rcpp::List::create(Rcpp::Named("A")=A);
> | }
> |
> |
> |
> |
> | ----------------------------------------------------------------------
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> --
> Dirk Eddelbuettel | edd at debian.org | http://dirk.eddelbuettel.com
>
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