f = rand(3);
g = rand(3);
resolutions = [1 1];

df_n= Derivatives_NGF_n(f,g,resolutions);
df_v= Derivatives_NGF_v(f,g,resolutions);

df_v = sum(df_v,2);

df_n_df_v_isEqual = [df_n(:) df_v(:) (abs(df_n(:)-df_v(:)) < 10e-3)]