[go: up one dir, main page]
Menu ▾ ▴

[r377]: / fish_shark / ran4.c  Maximize  Restore  History

Download this file

26 lines (24 with data), 643 Bytes 

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
float ran4(long *idum)

{

	void psdes(unsigned long *lword, unsigned long *irword);

	unsigned long irword,itemp,lword;

	static long idums = 0;

#if defined(vax) || defined(_vax_) || defined(__vax__) || defined(VAX)

	static unsigned long jflone = 0x00004080;

	static unsigned long jflmsk = 0xffff007f;

#else

	static unsigned long jflone = 0x3f800000;

	static unsigned long jflmsk = 0x007fffff;

#endif



	if (*idum < 0) {

		idums = -(*idum);

		*idum=1;

	}

	irword=(*idum);

	lword=idums;

	psdes(&lword,&irword);

	itemp=jflone | (jflmsk & irword);

	++(*idum);

	return (*(float *)&itemp)-1.0;

}

/* (C) Copr. 1986-92 Numerical Recipes Software )&%. */