RCPP警告:对"exp"的调用含糊不清 [英] Rcpp warning: Call to 'exp' is ambiguous

问题描述

我正在编写一个Rcpp代码，如下所示:

I am writing a Rcpp code as below:

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

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

using namespace Rcpp;
using namespace std;

// [[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);
    }

.

但是它表明调用'exp'是模棱两可的".为什么会收到此消息，我将如何解决?

But it shows that "Call to 'exp' is ambiguous". Why do I get this message and how will I solve it?

当我进入sessionInfo()时:

While I get in sessionInfo():

        R version 3.2.4 (2016-03-10)
        Platform: x86_64-apple-darwin13.4.0 (64-bit)
        Running under: OS X 10.12.6 (unknown)

locale:
[1] en_GB.UTF-8/en_GB.UTF-8/en_GB.UTF-8/C/en_GB.UTF-8/en_GB.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] Rcpp_0.12.4

loaded via a namespace (and not attached):
 [1] colorspace_1.2-6 scales_0.4.0     plyr_1.8.3       tools_3.2.4       inline_0.3.14    gtable_0.2.0     rstan_2.9.0-3   
 [8] gridExtra_2.2.1  ggplot2_2.1.0    grid_3.2.4       munsell_0.4.3    stats4_3.2.4  

推荐答案

我建议OP将其关闭或删除.这个问题只是展示了一些允许但不建议使用的C ++用法:

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

• 包括了额外的标头:数学标头 已由Rcpp引入(由RcppArmadillo引入)
• 您永远都不需要两者 cmath 和 math.h ，而且如此处所述，您也不需要
• 我们通常建议不要无条件地平整所有名称空间

• 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

这样，您的代码看起来像这样(仍然包含未使用的C ++ 11调用，但没有害处):

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)
*/

这在我的盒子上编译时没有任何警告(打开了严格的编译器警告，此处未显示输出)并且也按预期运行:

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> 

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