naurng.h
No OneTemporary
Actions

Authored By

Unknown

Size

1 KB

Referenced Files

None

Subscribers

None

naurng.h
View Options

	/* naurng.h : definitions for using Don Knuth's random number generator.
	This version uses the attribute TLS_ATTR from nauty.h.

	To use it:
	1. Call ran_init(seed) with any long seed. (Optional,
	but you will always get the same sequence otherwise.)
	2. Use NEXTRAN to get the next number (0..2^30-1).
	Alternatively, use KRAN(k) to get a random number 0..k-1.
	For large k, KRAN(k) is not quite uniform. In that case
	use GETKRAN(k,var) to set the variable var to a better
	random number 0..k-1.
	*/

	#ifndef NAURNG_H
	#include "nauty.h"

	#ifdef __cplusplus
	extern "C" {
	#endif

	void ran_init(long seed);
	long ran_nextran(void);

	#ifdef __cplusplus
	}
	#endif

	#define MAXRAN (0x3fffffffL) /* Values are 0..MAXRAN */
	#define NEXTRAN (ran_nextran())
	#define KRAN(k) (NEXTRAN%(k))
	#define RANREAL ((NEXTRAN+0.5)/(MAXRAN+1.0)) /* Uniform (0,1) */

	#define MAXSAFE(k) (((MAXRAN+1)/(k))*(k))
	#define GETKRAN(k,var) {long __getkran; \
	do {__getkran = NEXTRAN;} while (__getkran >= MAXSAFE(k)); \
	var = __getkran % (k);}
	#define INITRANBYTIME ran_init((long)time(NULL))

	#define NAURNG_H
	#endif