[Rcpp-devel] R.e. element wise multiplication of a subcube and a row of a matrix

I am posting again a question about the subject cited. I tried to search
this problem but did not find. My question is why we cannot multiply
element wise a subcube and a row of a matrix.

Any help would be appriciated. The following is sample code which is giving
erros about the operand %.


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

arma::rowvec sub(arma::cube a, arma::mat b)
{
        rowvec x  =  a.subcube(0, 0, 0, 0, 2, 0)% b.row(0);
        return x;
}