
Re: Summation in Mathematica
Posted:
Apr 26, 2013 4:24 AM


Am 24.04.2013 13:02, schrieb Ben Blomberg: > Hello All, > > I am trying to understand a piece of code I found but I am stuck on this > summation. This is part of a larger do loop over n. > > UnderoverscriptBox[\(\[Sum]\), \(m = \(10\)\), > \(10\)]\(\(eigenfunctionsort[n, j]\)[\([m + 11]\)] > Exp[I*2*\[Pi]*m*x/dp]\)\),{j,1,21}] > > What I mainly do not understand is what is happening with the [m+11]. Is > that being multiplied with eigen function sort with each step in the sum, > or is that simply adding 11 to m at each step in the sum?
The piece of code should be read in InputForm
Sum[eigenfunctionsort[n, j][[m + 1]] * Exp[2 *\[Pi] *I *m *x /dp], {m, 10, 10}]
In FullForm, eigenfunctionsort[n, j][[m + 1]] means
Part[eigenfunctionsort[n, j],m+1],
the m+1component of the vector of eigenfunctions probably with quantum numbers n and j.

Roland Franzius

