cdef class KF1D:
cdef public:
double x0_0
double x1_0
double K0_0
double K1_0
double A0_0
double A0_1
double A1_0
double A1_1
double C0_0
double C0_1
double A_K_0
double A_K_1
double A_K_2
double A_K_3