“…For fractional calculus equations, one generally can not get the solution in closed form, thus different numerical methods have been proposed to efficiently obtain the approximate solution, see [2,5,7,8,10,20,21,24,25,31,38,41,43,49]. As is well known that the solution of fractional differential equations shows some singularity at the initial node, different techniques were employed to restore the optimal convergence rate, see [15,23,26,27,40,42,44,45,47]. For equations with distributed order calculus, things seem worse as the distributed order calculus is a natural generalization of the fractional calculus and hence is more complicated.…”