#include <math.h>#define NRANSI#include "nrutil.h"void qrdcmp(float **a, int n, float *c, float *d, int *sing){	int i,j,k;	float scale,sigma,sum,tau;	*sing=0;	for (k=1;k<n;k++) {		scale=0.0;		for (i=k;i<=n;i++) scale=FMAX(scale,fabs(a[i][k]));		if (scale == 0.0) {			*sing=1;			c[k]=d[k]=0.0;		} else {			for (i=k;i<=n;i++) a[i][k] /= scale;			for (sum=0.0,i=k;i<=n;i++) sum += SQR(a[i][k]);			sigma=SIGN(sqrt(sum),a[k][k]);			a[k][k] += sigma;			c[k]=sigma*a[k][k];			d[k] = -scale*sigma;			for (j=k+1;j<=n;j++) {				for (sum=0.0,i=k;i<=n;i++) sum += a[i][k]*a[i][j];				tau=sum/c[k];				for (i=k;i<=n;i++) a[i][j] -= tau*a[i][k];			}		}	}	d[n]=a[n][n];	if (d[n] == 0.0) *sing=1;}#undef NRANSI