fig = plt.figure()
# ax = fig.gca(projection='3d')
# surf = ax.plot_surface(X, Y, phi,rstride=1, cstride=1,cmap = cm.jet,linewidth=0, antialiased=False)
# fig.colorbar(surf, shrink=0.5, aspect=5)
# plt.title('3-D Surface plot of the potential')
# plt.xlabel('x')
# plt.ylabel('y')
# plt.show()