[Rcpp-devel] Error for exp() using RcppArmadillo

Amina Shahzadi aminashahzadi at gmail.com
Mon Sep 12 05:29:57 CEST 2016

Hello Dear

I am new user of RcppArmadillo and Rcpp.
I am using a sample function pasted here.  I am haivng error given below:
Any can help in this regard.

In function ‘arma::vec sample(arma::vec, arma::vec)’:
sample.cpp:23:35: error: could not convert
from ‘double’ to ‘arma::vec {aka arma::Col<double>}’
      return exp(alpha1(0)+beta1(1));
sample.cpp:34:1: warning: control reaches end of non-void function

My function sample.cpp is below.

#include <RcppArmadillo.h>
using namespace Rcpp;
using namespace RcppArmadillo;

arma::vec sample(arma::vec alpha, arma::vec beta)
        int m = alpha.size();
        arma::uvec index(m);
        for(int i=0; i<m; i++)
                index(i) = i;
        for(int i=0; i<m; i++)
                for(int j=0; j<m; j++)
                                        arma::vec alpha1 =
alpha.elem(find(index !=j));
                                        arma::vec beta1 =
                                        return exp(alpha1(0)+beta1(1));
                                        arma::vec  alpha2 =
alpha.elem(find(index !=i && index !=j));
                                        arma::vec beta2 =
beta.elem(find(index !=i && index !=j));
                                        return exp(alpha2+beta2);


*Amina Shahzadi*
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