Re: decrementing problem

*To*: mathgroup at smc.vnet.net*Subject*: [mg72314] Re: [mg72293] decrementing problem*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Tue, 26 Dec 2006 04:47:00 -0500 (EST)*Organization*: Mathematics & Statistics, Univ. of Mass./Amherst*References*: <200612181156.GAA02194@smc.vnet.net>*Reply-to*: murray at math.umass.edu

Why bother with a For loop when Mathematica can handle the details for you: n=5; U=Table[Random[Real],{i,n},{j,n}]; X=Table[Random[Real],{j,n}]; Sum[U[[i,j]] X[[j]],{i,n-1,1,-1},{j,i+1,n}] 0.832632 jltrahan at mail.usf.edu wrote: > Hi, > I am having a really difficult time with decrementing values in my For > loop. I have tried i--, --i, i-=1, i=i-1, and nothing is working. The loop > is as follows: > For[i=n-1, i<=1, i--, summ=0; > For[j=i+1, j<=n, j++, summ=summ + U[[i,j]]*X[[j]]] > ] > When I try to print i or j, nothing shows up. > Can anyone please help? > > Thank you in advance, > Jamie > -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305

**References**:**decrementing problem***From:*jltrahan@mail.usf.edu