gasdev.c

来自「< C语言数值算法程序大全>>配套程序」· C语言 代码 · 共 25 行

#include <math.h>

float gasdev(long *idum)
{
	float ran1(long *idum);
	static int iset=0;
	static float gset;
	float fac,rsq,v1,v2;

	if  (iset == 0) {
		do {
			v1=2.0*ran1(idum)-1.0;
			v2=2.0*ran1(idum)-1.0;
			rsq=v1*v1+v2*v2;
		} while (rsq >= 1.0 || rsq == 0.0);
		fac=sqrt(-2.0*log(rsq)/rsq);
		gset=v1*fac;
		iset=1;
		return v2*fac;
	} else {
		iset=0;
		return gset;
	}
}