Re: Help with an error with NonlinearModelFit, Mathematica 7.0
- To: mathgroup at smc.vnet.net
- Subject: [mg99600] Re: Help with an error with NonlinearModelFit, Mathematica 7.0
- From: dh <dh at metrohm.com>
- Date: Fri, 8 May 2009 00:21:18 -0400 (EDT)
- References: <gtudh6$it8$1@smc.vnet.net>
Hi,
ak^2 is interpreted as the square of ak, hardly what you want.
Here is an example:
=============================
a =.; b =.; c =.;
data = Table[{k, Log[a k^2 + b k + c]}, {k, 1, 50}] /. {a -> 1,
b -> 2, c -> 3};
nlm = NonlinearModelFit[data, Log[a k^2 + b k + c], {a, b, c}, k]
=============================
Daniel
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?
>