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

[Amina Shahzadi]

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
‘exp((alpha1.arma::Col<double>::<anonymous>.arma::Mat<eT>::operator()<double>(0u)
+
beta1.arma::Col<double>::<anonymous>.arma::Mat<eT>::operator()<double>(1u)))’
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
[-Wreturn-type]
 }

My function sample.cpp is below.



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

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++)
                {
                        if(i==j)
                                {
                                        arma::vec alpha1 =
alpha.elem(find(index !=j));
                                        arma::vec beta1 =
beta.elem(find(index!=j));
                                        return exp(alpha1(0)+beta1(1));
                                }
                                else
                                {
                                        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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