#include <math.h>#define PI 3.141592654float poidev(float xm, long *idum){	float gammln(float xx);	float ran1(long *idum);	static float sq,alxm,g,oldm=(-1.0);	float em,t,y;	if (xm < 12.0) {		if (xm != oldm) {			oldm=xm;			g=exp(-xm);		}		em = -1;		t=1.0;		do {			++em;			t *= ran1(idum);		} while (t > g);	} else {		if (xm != oldm) {			oldm=xm;			sq=sqrt(2.0*xm);			alxm=log(xm);			g=xm*alxm-gammln(xm+1.0);		}		do {			do {				y=tan(PI*ran1(idum));				em=sq*y+xm;			} while (em < 0.0);			em=floor(em);			t=0.9*(1.0+y*y)*exp(em*alxm-gammln(em+1.0)-g);		} while (ran1(idum) > t);	}	return em;}#undef PI