double sinc(double x);
double sinc_p(double x);
double sinc_pp(double x);
double  coe_rhs(double x); 
double  w_1(double x); 
double  w_2(double x); 
double  coe_spline1(double x); 
double  coe_sincs(double x); 
double  coe_spline2(double x); 
double  psi(double x); 
double  Sphi(int j, double h, double x); 
double  u(double x); 
double  u_p(double x);