FunctionName Mark ofIntroduction Purpose d04aac Example Text 23 nag_numdiff_1d_real Numerical differentiation, derivatives up to order 14, function of one real variable d04bac Example Text 23 nag_numdiff_1d_real_eval Numerical differentiation, user-supplied function values, derivatives up to order $14$, derivatives with respect to one real variable d04bbc 23 nag_numdiff_1d_real_absci Generates sample points for function evaluations by nag_numdiff_1d_real_eval (d04bac)