“…As mentioned above, how to compute the integral tn 0 e −λ(tn+1−τ ) (t n+1 −τ ) α−1 f (τ, x(τ ))dτ efficiently is the key of reducing the computation cost to obtain the numerical approximations to x(t n+1 ). In the previous predictor-corrector work introduced in [7,8,9], as well as its improved version in [5,6], n steps' calculations are used to approximate the integral tn 0 · dτ . While, by noticing that (t n+1 − τ ) α−1 decays with power 1 − α, and e −λ(tn+1−τ ) damps exponentially (see figures below), we can actually select less mesh points, say 0 = τ 0,n < τ 1,n < · · · < τ mn,n = t n , (2.6) at which to approximate the term tn 0 · dτ by compounding two-point trapezoidal quadrature formula.…”