[Rcpp-devel] Working with arma::cube
Try this:
library(RcppArmadillo)
library(inline)
if( require( RcppArmadillo ) ){
fx <- cxxfunction( signature(x = "vector", n = "integer") , '
Rcpp::NumericVector XX(x);
Rcpp::IntegerVector dim(n);
arma::cube AY(XX.begin(), dim[0], dim[1], dim[2]);
return(wrap(AY));
', plugin = "RcppArmadillo" )
}
set.seed(10)
x = array(rnorm(25*25*10), dim=c(25,25,10))
y = fx(x, c(25,25,10))
all.equal(x,y)
Regards,
Alexios
On 06/03/2013 01:15, Dirk Eddelbuettel wrote:
On 6 March 2013 at 00:50, Silkworth,David J. wrote: | I am helping a student build some R code in Rcpp for his first time. He is | working with 3-dimensional arrays, so I am hopeful to be working with | arma::cube objects. | | When I simply try to bring the array in as an argument I can?t seem to use the | same as<[TEMPLATE]> construction as other objects. | | arma::cube X=Rcpp::as<arma::cube>(arg1); | | This line fails to compile. Yes. Nobody wrote such a converter. Maybe you and your student want to take a stab? | I can build this cube from an input vector using explicit nested loops. I also | notice that wrap() does a fine job of returning the array back to R. | | Is there anything else I need to know to more simply bring the array in as an | SEXP and land it in the arma::cube. Array plus dim attribute may work. I used arma::cube quite extensively in one project, but only at the C++ level as a container. Results back to R were always of lesser dimension. Dirk