#include <math.h>#define EPS 3.0e-14#define PIM4 0.7511255444649425#define MAXIT 10void gauher(float x[], float w[], int n){	void nrerror(char error_text[]);	int i,its,j,m;	double p1,p2,p3,pp,z,z1;	m=(n+1)/2;	for (i=1;i<=m;i++) {		if (i == 1) {			z=sqrt((double)(2*n+1))-1.85575*pow((double)(2*n+1),-0.16667);		} else if (i == 2) {			z -= 1.14*pow((double)n,0.426)/z;		} else if (i == 3) {			z=1.86*z-0.86*x[1];		} else if (i == 4) {			z=1.91*z-0.91*x[2];		} else {			z=2.0*z-x[i-2];		}		for (its=1;its<=MAXIT;its++) {			p1=PIM4;			p2=0.0;			for (j=1;j<=n;j++) {				p3=p2;				p2=p1;				p1=z*sqrt(2.0/j)*p2-sqrt(((double)(j-1))/j)*p3;			}			pp=sqrt((double)2*n)*p2;			z1=z;			z=z1-p1/pp;			if (fabs(z-z1) <= EPS) break;		}		if (its > MAXIT) nrerror("too many iterations in gauher");		x[i]=z;		x[n+1-i] = -z;		w[i]=2.0/(pp*pp);		w[n+1-i]=w[i];	}}#undef EPS#undef PIM4#undef MAXIT