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NonlinearFit: Parameter range not working ??

  • To: mathgroup at
  • Subject: [mg21183] NonlinearFit: Parameter range not working ??
  • From: B Hamond <b_hamond at>
  • Date: Fri, 17 Dec 1999 01:23:37 -0500 (EST)
  • Organization: None
  • Sender: owner-wri-mathgroup at


I'm using NonlinearFit (actually NonlinearRegress) to fit a function to
some data points. Some of the parameters must not fall below 0, so I
specified the parameters as {symbol, start, min,max} with min being
zero. However, NonlinearFit seems to ignore the range specification and
keeps assigning negative values to the parameter while it's trying to
find the best fit. But then of course it stops with an error message
like: Objective function is not real at {i,g}={-2.2x10^-6, 0.1}.

What am I doing wrong ?

Btw. this is with Mathematica 4 under Windows NT.

                        Axel Kowald


Dr. Axel Kowald                                  Email:
a.kowald at
Humboldt University Berlin                       Tel:   +49 30 20939105
Innovationskolleg Theoretische Biologie          Fax:   +49 30 20938801
Invalidenstr. 43
10115 Berlin


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