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Re: Help with an error with NonlinearModelFit, Mathematica 7.0

  • To: mathgroup at smc.vnet.net
  • Subject: [mg99601] Re: Help with an error with NonlinearModelFit, Mathematica 7.0
  • From: Bill Rowe <readnews at sbcglobal.net>
  • Date: Sat, 9 May 2009 03:19:21 -0400 (EDT)

On 5/7/09 at 6:35 AM, mgao4793 at gmail.com (Anonymous) wrote:

>I'm trying to find a fit to a large set of data.

>Here are In[1], In[2].

>In[1] := {{421.1, 6591.10}, ...};

>(there are way more points, in fact there are 35 in total, but I
>don't want to list them.  All are real numbers.)

>In[2] := nlm = NonlinearModelFit[data, Log[ak^2 + bk + c], {a,b,c},
>k]

>Then mathematica gives an error that basically says that the
>function "is not a list of real numbers"

>Of course it is, so how do I fix this?

Are you sure? How did you verify there were no non-numeric
elements in your data?

Try doing Union[Head/@Flatten[data]] where data is the array you
are feeding into NonlinearModelFit. That will return a list of
all data types in the array. Does it contain anything other than
Integer, Real or Rational? If so, that is the problem.




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