BCC-16 (in Chinese) 計算機概論十六講 R -- Standalone

R 教材：Standalone

This page is for Linux only!!

Reference
For the detail to read the web page The R Manuals.
And the PDF document Writing R Extensions (Chapter 5.13) in The R Manuals or my mirror here.

Recompile
The default installation (RPM or compile from source) of R doesn't build the standalone library, since, do it yourself.
Download the source R-1.7.1.tgz or my mirror here (9MB). And follows,

SHELL> tar zxvf R-1.7.1.tgz
SHELL> cd R-1.7.1/
SHELL> ./configure; make
SHELL> cd src/nmath/standalone/
SHELL> make shared
SHELL> cp libRmath.so /usr/lib/R/bin/
SHELL> cd /usr/lib
SHELL> ln -s /usr/lib/libRmath.so ./R/bin/libRmath.so

The subdirectory "src/nmath/standalone/" is the source of Mathlib for standalone library "libRmath".
The "Rmath.h" (in /usr/lib/R/include/) is the R set of mathematical functions.
The fils "libRmath.so" is the sared library for Linux.
Suggest to copy the library files to "/usr/lib/R/bin/".

PS: Not support in this page

The file "libRmath.a" is the static library for Linux. Use "make static" to subsitute "make shared".
The file "libRmath.dll" is the dynamic loaded library for Windows.

Main code
The C code "stand.c" will set the seed and generate 10 random variables from standard normal (mu = 0, sigma = 1) and compute theirs cumulative probability.

#define MATHLIB_STANDALONE
#include <Rmath.h>

int main(){
  int i;
  unsigned int SEED1, SEED2;
  double mu, sigma, PHI_X, *X;

  mu = 0;
  sigma = 1;
  SEED1 = 12345;
  SEED2 = 67890;
  set_seed(SEED1, SEED2);

  X = (double *) malloc(10);
  for(i = 0; i < 10; i++){
    X[i] = rnorm(mu, sigma);
    PHI_X = pnorm(X[i], mu, sigma, 1, 0);
    printf("X: %f, PHI(X): %f\n", X[i], PHI_X);
  }
}

Compile
Linux:

SHELL> gcc -o stand stand.c -I/usr/lib/R/include/ -lRmath -lm

And the output will be a executable file "stand" (for linux only).

Output
The output as follow,

X: 0.999948, PHI(X): 0.841332
X: -1.768380, PHI(X): 0.038499
X: 0.623938, PHI(X): 0.733666
X: 2.167754, PHI(X): 0.984911
X: 0.749400, PHI(X): 0.773192
X: -1.253019, PHI(X): 0.105099
X: 0.640719, PHI(X): 0.739147
X: 0.567502, PHI(X): 0.714814
X: -1.744883, PHI(X): 0.040503
X: 0.140647, PHI(X): 0.555925


	陳韋辰 (04/08/19) ---