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Non linear fit help

Hi all,

I am trying to fit a series of data using a non linear equation. I have tried with the NonlinearModelFit function but it gives me unsatisfactory answer.

I am attaching the data file I am working on and the non linear equation.

Any help is appreciated.

Attachments:
POSTED BY: suvadip mandal
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  1. What values for the parameters are more reasonable? Try using these as starting values for FindFit.
  2. What is this equation? Is it the CDF of the distribution? The PDF of the distribution? If so, your data doesn't make any sense.
POSTED BY: Sean Clarke

Sir,

I tried to use the FindFit function but again I have got something which should not get. I have attached the file and please tell me what is wrong.

I have got this data from an experiment and all I know is that the fit should be a double Gaussian fit of that structure.

Attachments:
POSTED BY: suvadip mandal
POSTED BY: Sean Clarke

Sir,

My expected fit is a double Gaussian fit. The parameters are n, a and b. The independent variable is x. I am attaching the mathematica file. Perhaps this will help.

Attachments:
POSTED BY: suvadip mandal

Finally, looking at your formula...

Is x the independant variable in the formula? If so you might be able to transform the x values so this is a linear problem.

x = Sqrt[Log[newx]]

E^(x^2) = newx

When x>1 this is an injective map that linearizes your equation.. unless I'm missing something.

POSTED BY: Sean Clarke
POSTED BY: Sean Clarke
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