Re: NonlinearFit + Sums

*To*: mathgroup at smc.vnet.net*Subject*: [mg68799] Re: NonlinearFit + Sums*From*: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>*Date*: Sat, 19 Aug 2006 00:41:03 -0400 (EDT)*Organization*: The Open University, Milton Keynes, UK*References*: <ec3q7k$2fd$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Lyta wrote: > Hi, > > I want to do a mulitdimensional nonlinear fitting and I'm not sure how to define the mathematica statement for that. > > I have a matrix "data" of dimensions 140x37 that contains 36 samples of 140 functions. The 37th column contains the resulting value of a mapping of the type R36->R1. I want to calculate the parameter mu of a function that integrates over the samples - i posted a simplified version of the function below. My problem is, that I don't know what to write instead of x_i. For the second x_ it should be something like {x1, x2, x3, x4, ..., x36}. But the first x_i should be something like x[[i]] (this doesn't work ofc). How do i assign the data to the sum? > > NonlinearFit[data, Sum[E^(mu)*x_i, {i, 1, 36}], x_i, {mu}] > > I hope you can help :-) > The following should do what your are looking for: data = Table[Random[], {140}, {37}]; model = Plus @@ Table[E^mu*x[i], {i, 1, 36}] Needs["Statistics`NonlinearFit`"] NonlinearFit[data, model, Table[x[i], {i, 1, 36}], {mu}] HTH, Jean-Marc