“…Therefore, every effort has been put to develop the efficient and stable numerical techniques. To solve the convection-diffusion equation, a huge body of research on proficient numerical methods, such as the finite element method (see, e.g., [3][4][5]), the finite difference method (see, e.g., [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]), and others, has been created. We now concentrate on the research about the finite difference method.…”