void differ_backward ( double h, int o, int p, double c[], double x[] );
void differ_central ( double h, int  o, int p, double c[], double x[] );
void differ_forward ( double h, int o, int p, double c[], double x[] );
double *differ_inverse ( int n, double stencil[] );
double *differ_matrix ( int n, double stencil[] );
double *differ_solve ( int n, double stencil[], int order );
void differ_stencil ( double x0, int o, int p, double x[], double c[] );
double inverse_error ( int n, double a[], double b[] );
int i4_max ( int i1, int i2 );
int i4_min ( int i1, int i2 );
double r8_factorial ( int n );
double *r8mat_fs_new ( int n, double a[], double b[] );
double *r8mat_mm_new ( int n1, int n2, int n3, double a[], double b[] );
double *r8mat_mv_new ( int m, int n, double a[], double x[] );
double r8mat_norm_fro ( int m, int n, double a[] );
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 );
double *r8mat_sub_new ( int m, int n, double a[], double b[] );
void r8vec_print ( int n, double a[], char *title );
double *r8vec_uniform_01_new ( int n, int *seed );
void r8vec2_print ( int n, double a1[], double a2[], char *title );
void r8vm_sl ( int n, double a[], double b[], int job, double x[], int *info );
double *r8vm_sl_new ( int n, double a[], double b[], int job, int *info );
void timestamp ( );