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Fit with implicit nonlinear function - Matlab

  1. Oct 19, 2015 #1
    Hi guys! I am trying to fit a function whose x data depends nonlinearly on the parameter of the fit and I am having hard time doing that!
    I will explain better: from my experiment I was able to measure my ydata e my x0 array and I know that my xdata are:
    x=x0+a/(1+4x^2), with a being a parameter of the fit that I need to find.
    After found a I can try to fit my data knowing my fitting function F(x,b) with b another parameter of the fit.
    I managed to find a "brute" way to find the best a parameter for my data, by simply making it change and measuring the difference between my fitting function and my ydata. But know that I have to add a second parameter to the fit I really don't know what to do! Any help?
    Thanks a lot
  2. jcsd
  3. Oct 22, 2015 #2


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    Gold Member

    It is difficult to ascertain your problem based on your post. Can you please post a self-contained piece of code instead? Then it will be easier for other people to run your code and help you fix it or add to it.
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