double *hammersley ( int i, int m, int n );
int hammersley_inverse ( double r[], int m, int n );
double *hammersley_sequence ( int i1, int i2, int m, int n );
int i4vec_sum ( int n, int a[] );
int prime ( int n );
void r8mat_print ( int m, int n, double a[], char *title );
void r8mat_print_some ( int m, int n, double a[], int ilo, int jlo, int ihi,
  int jhi, char *title );
void timestamp ( );