gsl_microrng.h File Reference

#include <gsl/gsl_rng.h>
#include <string.h>

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Macros
#define	GSL_MICRORNG(NAME, CBRNGNAME)

Macro Definition Documentation

GSL_MICRORNG

#define GSL_MICRORNG	(		NAME,
			CBRNGNAME
	)

The macro: GSL_MICRORNG(NAME, CBRNGNAME) is the GSL analog analog of the C++ r123::MicroURNG template. It declares a gsl_rng type named gsl_rng_NAME which uses the underlying CBRNGNAME and can be invoked a limited number of times between calls to NAME_reset.

When the underlying CBRNG's ctr_t is an r123arrayNxW, and the gsl_rng_NAME may called up to N*2^32 times between calls to NAME_reset.

NAME_reset takes a gsl_rng_NAME type, a counter and a key as arguments. It restarts the micro-rng with a new base counter and key.

Note that you must call NAME_reset before the first use of a gsl_rng. NAME_reset is not called automatically by gsl_rng_alloc().

#include <Random123/threefry.h>
#include <Random123/gsl_microrng.h> // this file
GSL_MICRORNG(microcbrng, threefry4x64, 20)      // creates gsl_rng_microcbrng
 
int main(int argc, char** argv) {
     gsl_rng *r = gsl_rng_alloc(gsl_rng_microcbrng);
     threefry4x64_ctr_t c = {{}};
     threefry4x64_key_t k = {{}};
 
     for (...) {
         c.v[0] = ??; //  some application variable
         microcbrng_reset(r, c, k);
         for (...) {
        // gaussian calls r several times.  It is safe for
        // r to be used upto 2^20 times in this loop
        something[i] = gsl_ran_gaussian(r, 1.5);
         }
     }
}