added optional RCPP_ARMADILLO_RETURN_COLVEC_AS_VECTOR and co.

[sgsokol]

I don't know how to add unit tests with RUnit so tested by hand with code snipets like the following:

legacy colvec

> sourceCpp(code="// [[Rcpp::depends(RcppArmadillo)]]\n#include <RcppArmadillo.h>\n// [[Rcpp::export]]\narma::vec add1(arma::vec x) {return(x+1);}")
> add1(1:2)
     [,1]
[1,]    2
[2,]    3

colvec tested with COLVEC

> sourceCpp(code="// [[Rcpp::depends(RcppArmadillo)]]\n#define RCPP_ARMADILLO_RETURN_COLVEC_AS_VECTOR\n#include <RcppArmadillo.h>\n// [[Rcpp::export]]\narma::vec add1v(arma::vec x) {return(x+1);}")
> add1v(1:2)
[1] 2 3

colvec tested with ANYVEC

> sourceCpp(code="// [[Rcpp::depends(RcppArmadillo)]]\n#define RCPP_ARMADILLO_RETURN_ANYVEC_AS_VECTOR\n#include <RcppArmadillo.h>\n// [[Rcpp::export]]\narma::vec add1v(arma::vec x) {return(x+1);}")
> add1v(1:2)
[1] 2 3

legacy rowvec

> sourceCpp(code="// [[Rcpp::depends(RcppArmadillo)]]\n#include <RcppArmadillo.h>\n// [[Rcpp::export]]\narma::rowvec add1r(arma::rowvec x) {return(x+1);}")
> add1r(1:2)
     [,1] [,2]
[1,]    2    3

rowvec tested with ROWVEC

> sourceCpp(code="// [[Rcpp::depends(RcppArmadillo)]]\n#define RCPP_ARMADILLO_RETURN_ROWVEC_AS_VECTOR\n#include <RcppArmadillo.h>\n// [[Rcpp::export]]\narma::rowvec add1rv(arma::rowvec x) {return(x+1);}")
> add1rv(1:2)
[1] 2 3

rowvec tested with ANYVEC

> sourceCpp(code="// [[Rcpp::depends(RcppArmadillo)]]\n#define RCPP_ARMADILLO_RETURN_ANYVEC_AS_VECTOR\n#include <RcppArmadillo.h>\n// [[Rcpp::export]]\narma::rowvec add1rv(arma::rowvec x) {return(x+1);}")
> add1rv(1:2)
[1] 2 3

Signed-off-by: Serguei Sokol

[eddelbuettel]

First off, thanks for getting this started!

Second, I edited your markdown. Level headers (one #) are 'too loud'; I made them level four. And I made your code snippets code snippets. See what I did there, and read up on Markdown and GitHub-flavoured Markdoiwn. It is worth it.

Third, this must have new unit tests. Adding them is trivial. Just look at the subdirectory and the runit.* files along with the supporting cpp/ directory and it should become clear. We may need several .cpp files with/without the defines.

[eddelbuettel]

This looks fine but is too minimal and bare.

We need unit tests.

We probably need a commented-out but documenting setting in RcppArmadilloConfig.h.

[eddelbuettel]

That looks good. I'll add ChangeLog and NEWS entries.