source: Sophya/trunk/ArchTOIPipe/Processors/dludcmp.c@ 3795

#include <math.h>
#define NRANSI
#define TINY 1.0e-20;

void nrerror(char error_text[]);
double *dvector(long nl, long nh);
void free_dvector(double *v, long nl, long nh);
int dludcmp(double **a, int n, int *indx, double *d);

int dludcmp(double **a, int n, int *indx, double *d)
{
        int i,imax,j,k;
        double big,dum,sum,temp;
        double *vv;

        vv=dvector(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) return -1;
                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_dvector(vv,1,n);
        return 0;
}
#undef TINY
#undef NRANSI