problem with nonlinear fit
- To: mathgroup at smc.vnet.net
- Subject: [mg25477] problem with nonlinear fit
- From: "Dragan Grgic" <Dragan.Grgic at ensg.inpl-nancy.fr>
- Date: Mon, 2 Oct 2000 22:26:56 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Hi everybody, I have to fit the function e = (s/K)^(Na)*(t/a)^a (s = constant; t = variable; K,N,a = parameters) to a given set of datas. Then, I have used the NonlinearFit function (Statistics'NonlinearFit' package), but I have two problems: 1) I can't specify any start values or range using. I tried to give them as any forms, but I always got error messages concerning these parameters. 2) mathematica shows kind of a strange behavior when repeating the fit operation, sometimes it keeps old values and sometimes it reports different error messages. Any help welcome, Thanks in advance, Dragan.