Re: nonlinearmodelfit problem

*To*: mathgroup at smc.vnet.net*Subject*: [mg126053] Re: nonlinearmodelfit problem*From*: Alexei Boulbitch <Alexei.Boulbitch at iee.lu>*Date*: Fri, 13 Apr 2012 04:59:15 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

Hi my name is Lorenzo Mattera, I am using since a short time Mathematica. I am trying to solve a fitting problem where two sets of data have to be fitted by two models depending on the same parameters. I found very helpful the suggestions reported at http://forums.wolfram.com/mathgroup/archive/2011/Sep/msg00555.html (and references therein) so that I was able to produce a working procedure. However, I have a "small" problem: the two set of data have quite different weights as one is in the 0-100000 range while the other is in the 0-1 range so that one of the two is irrelevant in the fitting procedure. It seems to me that NonlinearModelFit minimizes the sum of the squared residuals, any way to minimize the squared normalized residuals? Perhaps is one of the options, but so far I could not find it. Tank you for the help best regards L. Mattera Hi, Lorenzo, I am not quite sure what did you exactly mean with "0-100000 range" and "0-1 range", x values range? y values range? Or numbers of data pairs. An example of such a data + the corresponding model would be helpful for understanding. Anyway, however, it seems that playing with Weights might help. Have a look into Menu/Help/Weights. Have fun, Alexei Alexei BOULBITCH, Dr., habil. IEE S.A. ZAE Weiergewan, 11, rue Edmond Reuter, L-5326 Contern, LUXEMBOURG Office phone : +352-2454-2566 Office fax: +352-2454-3566 mobile phone: +49 151 52 40 66 44 e-mail: alexei.boulbitch at iee.lu