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Fitting a very simple dataset

Posted 5 months ago
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Hi all,

I am a beginner in Mathematica. I am trying to fit the data from a CSV file using FindFit. In doing so, I am getting the following error message

FindFit::nrjnum: The Jacobian is not a matrix of real numbers at {a} = {1.}.

My CSV file can be found attached. I wonder what is the right way of performing this task. I would like to fit my data into something of the form:

y = 1/x^{a}

My attempt so far has been

data=Import["/home/data_variance2_r \_final.csv"]
modeltwolevelsat = 1/x^a;
eq = FindFit[data, modeltwolevelsat, {a}, x]

I would appreciate if someone can help me out or give any tip on how to solve this problem. Thanks in advance.

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3 Replies
Posted 5 months ago

Hi Heitor,

Look at what the function evaluates to over the data.

ClearAll@modeltwolevelsat;
modeltwolevelsat[x_, a_] = 1/x^a

modeltwolevelsat @@@ data
(* Result is imaginary *)
Posted 5 months ago

Crossposted here.

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