geqo_random.h

来自「PostgreSQL 8.2中增加了很多企业用户所需要的功能和性能上的提高,其开」· C头文件 代码 · 共 39 行

/*-------------------------------------------------------------------------
 *
 * geqo_random.h
 *	  random number generator
 *
 * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * $PostgreSQL: pgsql/src/include/optimizer/geqo_random.h,v 1.18 2006/03/05 15:58:57 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */

/* contributed by:
   =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
   *  Martin Utesch				 * Institute of Automatic Control	   *
   =							 = University of Mining and Technology =
   *  [e-mail]  * Freiberg, Germany				   *
   =*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
 */

/* -- parts of this are adapted from D. Whitley's Genitor algorithm -- */

#ifndef GEQO_RANDOM_H
#define GEQO_RANDOM_H

#include <math.h>

/* geqo_rand returns a random float value between 0 and 1 inclusive */

#define geqo_rand() ((double) random() / (double) MAX_RANDOM_VALUE)

/* geqo_randint returns integer value between lower and upper inclusive */

#define geqo_randint(upper,lower) \
	( (int) floor( geqo_rand()*(((upper)-(lower))+0.999999) ) + (lower) )

#endif   /* GEQO_RANDOM_H */