Non Linear Least Square Fit with GSL MultiFit

ROOT
4

Hi,
If you want to fit using the GSLMultiFit algorithm (the Levenberg-Marquardt algorithm) you can do in two ways:

  • either using the Fit method of the histogram of graph you want to fit.
  • or by providing yourself the chi2 function and using the ROOT::Fit::Fitter interface. In this second case your function must implement the ROOT::Math::FitMethodFunction interface, otherwise it will now work, because that algorithm needs to know all the chi2 contributions.
    See root.cern.ch/root/htmldoc/ROOT__ … iDim_.html

Best Regards

Lorenzo