Rcpp warning: Call to 'exp' is ambiguous

Question

I am writing a Rcpp code as below:

// [[Rcpp::depends(RcppArmadillo)]]
// [[Rcpp::depends(BH)]]
// [[Rcpp::plugins(cpp11)]]

#include 
#in         


        

Answer 1

I suggest this to be closed or deleted by OP. The question simply exhibits some allowed-but-not-recommended C++ usage:

• extra headers included: the math headers are already brought in by Rcpp (which is brought in by RcppArmadillo)
• you never ever need both cmath and math.h, and as stated here you do not need either
• we generally recommend against flattening all namespaces unconditionally

With this, your code looks like this (still containing a call for C++11 which is not used, but does no harm):

// [[Rcpp::depends(RcppArmadillo)]]
// [[Rcpp::depends(BH)]]
// [[Rcpp::plugins(cpp11)]]

#include <RcppArmadillo.h>
#include <boost/random.hpp>
#include <boost/random/uniform_real_distribution.hpp>

// [[Rcpp::export]]
double ks(const double k, const double alpha, const double  mag, const double M0){
    double ksres;
    ksres=  k* std::exp ( alpha*(mag-M0) );
    return(ksres);
}

/*** R
ks(1.0, 2.0, 3.0, 4.0)
*/

This compiles without any warning whatsoever on my box (with stringent compiler warnings turned on, output not shown here) and runs as expected too:

R> Rcpp::sourceCpp("/tmp/soQ.cpp")

R> ks(1.0, 2.0, 3.0, 4.0)
[1] 0.135335
R>