#define SWAP(a,b) {swap=(a);(a)=(b);(b)=swap;}void covsrt(float **covar, int ma, int ia[], int mfit){	int i,j,k;	float swap;	for (i=mfit+1;i<=ma;i++)		for (j=1;j<=i;j++) covar[i][j]=covar[j][i]=0.0;	k=mfit;	for (j=ma;j>=1;j--) {		if (ia[j]) {			for (i=1;i<=ma;i++) SWAP(covar[i][k],covar[i][j])			for (i=1;i<=ma;i++) SWAP(covar[k][i],covar[j][i])			k--;		}	}}#undef SWAP