#include <math.h>#define NRANSI#include "nrutil.h"#define TINY 1.0e-20;void ludcmp(float **a, int n, int *indx, float *d){	int i,imax,j,k;	float big,dum,sum,temp;	float *vv;	vv=vector(1,n);	*d=1.0;	for (i=1;i<=n;i++) {		big=0.0;		for (j=1;j<=n;j++)			if ((temp=fabs(a[i][j])) > big) big=temp;		if (big == 0.0) nrerror("Singular matrix in routine ludcmp");		vv[i]=1.0/big;	}	for (j=1;j<=n;j++) {		for (i=1;i<j;i++) {			sum=a[i][j];			for (k=1;k<i;k++) sum -= a[i][k]*a[k][j];			a[i][j]=sum;		}		big=0.0;		for (i=j;i<=n;i++) {			sum=a[i][j];			for (k=1;k<j;k++)				sum -= a[i][k]*a[k][j];			a[i][j]=sum;			if ( (dum=vv[i]*fabs(sum)) >= big) {				big=dum;				imax=i;			}		}		if (j != imax) {			for (k=1;k<=n;k++) {				dum=a[imax][k];				a[imax][k]=a[j][k];				a[j][k]=dum;			}			*d = -(*d);			vv[imax]=vv[j];		}		indx[j]=imax;		if (a[j][j] == 0.0) a[j][j]=TINY;		if (j != n) {			dum=1.0/(a[j][j]);			for (i=j+1;i<=n;i++) a[i][j] *= dum;		}	}	free_vector(vv,1,n);}#undef TINY#undef NRANSI