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Original Message (ID '161425') By Vojta:
In Response To 'Re: Slowdown of computation of multiple sums' --------- Let me rephrase my question. Lets say I want to make sum Sum[function[n],{n,min,max}] where function[n] is defined as function[n_]:=Sum[differentfunction[n,i,j,k],{i,imin,imax},{j,jmin,jmax},{k,kmin,kmax}] where differentfunction[n,i,j,k] can be quite complicated function which could even contain i-th derivatives of some genereting function etc. Now, when the sum over n is calculated, will it have to run internally in every term for every n all the summations over i,j,k which are in the definition of function[n]? Or will those sums be done at the beginning and then Mathematica will just insert values of n from nmin to nmax?