double *halton ( int i, int m );
double *halton_base ( int i, int m, int b[] );
int halton_inverse ( double r[], int m );
double *halton_sequence ( int i1, int i2, int m );
int i4vec_sum ( int n, int a[] );
int prime ( int n );
double r8_mod ( double x, double y );
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 ( );