bug fix: flux calculation
bug fix: flux calculation

li12242/NDGFEM_Matlab,li12242/NDG-FEM,li12242/NDGFEM_Matlab,li12242/NDGFEM_Matlab,li12242/NDG-FEM,li12242/NDGFEM_Matlab,li12242/NDG-FEM,li12242/NDG-FEM