[英]How to call a C function in R package
The package has name pareto
. 该软件包的名称为pareto
。 This is the .c
file in the src
directory: 这是src
目录中的.c
文件:
#include <R.h>
#include <math.h>
#include "Rinternals.h"
#include "R_ext/Rdynload.h"
static void dpareto(double *x, double *a, double *b, int *n, int *islog,
double *den){
int length = n[0];
int i;
int isLog = islog[0];
for (i = 0; i < length; i++){
if (a[i] > 0 && b[i] > 0) {
if (x[i] > a[i])
den[i] = log(b[i]) + b[i] * log(a[i]) - (b[i] + 1) * log(x[i]);
else
den[i] = R_NegInf;
if (!isLog)
den[i] = exp(den[i]);
}
else {
den[i] = R_NaN;
}
}
}
static R_CMethodDef DotCEntries[] = {
{"dpareto", (DL_FUNC) dpareto, 6},
{NULL}
};
void R_init_pareto(DllInfo *info)
{
R_registerRoutines(info, DotCEntries, NULL, NULL, NULL);
}
In R
directory, the corresponding .R
file is: 在R
目录中,相应的.R
文件为:
#' @useDynLib pareto
#' @export
dpareto <- function(x, a, b, log = FALSE) {
nx <- length(x)
na <- length(a)
nb <- length(b)
n <- max(nx, na, nb)
if (nx < n) x <- rep(x, length.out = n)
if (na < n) a <- rep(a, length.out = n)
if (nb < n) b <- rep(b, length.out = n)
rt <- .C("dpareto", as.double(x), as.double(a), as.double(b), as.integer(n),
as.integer(log), den = double(n), PACKAGE="pareto")
rt$den
}
After documented by roxygen
, the NAMESPACE
has: 经roxygen
记录后, NAMESPACE
具有:
export(dpareto)
useDynLib(pareto)
But the package cannot pass checking, and R
keeps generate error message that: 但是该程序包无法通过检查,并且R
不断生成以下错误消息:
"dpareto" not available for .C() for package "pareto"
Calls: dpareto -> .C
I really can't figure out which step I made a mistake. 我真的不知道我在哪一步做错了。
You added the static
keyword to your dpareto
function definition. 您将static
关键字添加到dpareto
函数定义中。 This means the function won't be exported, so R won't see it. 这意味着该函数将不会导出,因此R不会看到它。 Remove static
and try again. 删除static
然后重试。
trivial mistake. 琐碎的错误。 Just in void R_init_pareto
I used a wrong package name. 只是在void R_init_pareto
我使用了错误的程序包名称。 So silly mistake. 如此愚蠢的错误。
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