sphbes.c

Numerical Recipes in C的源代码

#include <math.h>
#define RTPIO2 1.2533141

void sphbes(int n, float x, float *sj, float *sy, float *sjp, float *syp)
{
	void bessjy(float x, float xnu, float *rj, float *ry, float *rjp,
		float *ryp);
	void nrerror(char error_text[]);
	float factor,order,rj,rjp,ry,ryp;

	if (n < 0 || x <= 0.0) nrerror("bad arguments in sphbes");
	order=n+0.5;
	bessjy(x,order,&rj,&ry,&rjp,&ryp);
	factor=RTPIO2/sqrt(x);
	*sj=factor*rj;
	*sy=factor*ry;
	*sjp=factor*rjp-(*sj)/(2.0*x);
	*syp=factor*ryp-(*sy)/(2.0*x);
}
#undef RTPIO2