fp coeff_dx_0_0_0,
   coeff_dx_p1_0_0,
   coeff_dx_0_p1_0,
   coeff_dx_p1_p1_0,
   coeff_dx_0_0_p1,
   coeff_dx_p1_0_p1,
   coeff_dx_0_p1_p1,
   coeff_dx_p1_p1_p1;