Fixed fd_coeff bug

Author: XZTian64

src/simulation/m_derived_variables.fpp

@@ -102,11 +102,11 @@ contains
             ! Computing centered finite difference coefficients
             call s_compute_finite_difference_coefficients(m, x_cc, fd_coeff_x, buff_size, &
                                                           fd_order, fd_number)
-            $:GPU_UPDATE(device='[fd_coeff_z]')
+            $:GPU_UPDATE(device='[fd_coeff_x]')
             if (n > 0) then
                 call s_compute_finite_difference_coefficients(n, y_cc, fd_coeff_y, buff_size, &
                                                               fd_order, fd_number)
-                $:GPU_UPDATE(device='[fd_coeff_z]')
+                $:GPU_UPDATE(device='[fd_coeff_y]')
             end if
             if (p > 0) then
                 call s_compute_finite_difference_coefficients(p, z_cc, fd_coeff_z, buff_size, &