Multiple sums.

*To*: mathgroup at smc.vnet.net*Subject*: [mg5759] Multiple sums.*From*: Gadi Oron <oron at tremois.pmmh.espci.fr>*Date*: Tue, 14 Jan 1997 10:42:32 -0500*Organization*: Acces regional Ile-de-France (Univ. Paris VI/VII) - France*Sender*: owner-wri-mathgroup at wolfram.com

Hi there, I would like to thank all of those who had replied to my previeous questions, that was very helpful. So now for a new one : I want to do a multiple sum with a variable number of variables (hehe) something of this type : Sum[f1(n[1],..,n[M])*Sum[f2(n[1],..,n[M])* ..., {n[1],1,g1(n[1],...)},...] so I wrote; (Well, i've copied it directly so the functions f and g are already there) sl[L_,n_]:=Module[{r=1-n/L,t,l}, t=(L r+1-Sum[l[p],{p,1,n-1}]); For[ii=n-1,ii>0,ii--, t=Sum[(1+l[ii])*t,{l[ii],0,L r-Sum[l[k],{k,1,ii-1}]}]; ]; Return[t]; ] Well, it is quite unreadeble but whats essential is that the ii in the range index won't evaluate, so the sums are made with (litterally) l[ii] and not with l[1],l[2] etc, I even tried to evaluate the ranges before, putting a={l[ii],0,L r-Sum[l[k],{k,1,ii-1}]} t=Sum[... ,a] But then MM yells that the range is incorrect. Any ideas? P.S. : Excuse me for being unclear about this one. See ya. /\/\/\/\/\/\/\/\/\/\/\/>> Gadi ORON <<\/\/\/\/\/\/\/\/\/\/\/\/\ | EMAIL : oron at pmmh.espci.fr :::: oron at clipper.ens.fr | | Homepage : http://pmmh.espci.fr/home/oron/WWW/personal.html | | fido : 2:325/302.8 | | Soyez braves - be brave. | /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/