Hi Alberto, Alberto Pulvirenti wrote: > > Thanks for the answer, I read the documentation and I fount answer to > all question, except one: > > I have understood that the LeastSquareLinearFit() method does a straight > line fit through the data. > But, it does not take into account the errors, because a common TGraph > has not errors in its points. > > In the case of a TGrapErrors object, does it perform the linear fit > weighting all points with its error, or not? Yes. Please read carefully the documentation of TGraph::Fit at: http://root.cern.ch/root/htmldoc/TGraph.html#TGraph:Fit Rene Brun > > Cheers, > Alberto > > On Thu, 2004-05-06 at 15:09, Rene Brun wrote: > > Hi Alberto, > > > > see the documentation of TGraph and TGraph::Fit, etc at: > > > > http://root.cern.ch/root/htmldoc/TGraph.html > > http://root.cern.ch/root/htmldoc/TGraph.html#TGraph:Fit > > http://root.cern.ch/root/htmldoc/TGraph.html#TGraph:LeastSquareLinearFit > > > > Rene Brun > > > > Alberto Pulvirenti wrote: > > > > > > Sorry, I forgot to put a topic in the email, and maybe many of you could > > > have deleted it as spam. > > > Here it is again. > > > > > > Cheers, > > > Alberto > > > > > > On Wed, 2004-05-05 at 15:38, Alberto Pulvirenti wrote: > > > > Dear ROOTers, > > > > > > > > I have seen that it is possible to fit a TGraphErrors object with a > > > > given TF1. > > > > > > > > My question is: does this fit take into account the errors which I pass > > > > to this object, or not? > > > > Maybe, must I specify something in order to accomplish this task? > > > > > > > > Another question: I saw in the class definition a method called > > > > > > > > virtual void LeastSquareLinearFit(Int_t n, Double_t& a0, Double_t& a1, > > > > Int_t& ifail, Int_t first, Int_t last) > > > > > > > > Does it fit (according to parameters names) to which of the following? > > > > 1) a0 + a1*x > > > > 2) a0*x + a1 > > > > > > > > What does 'ifail' mean? > > > > > > > > Thanks for all. > >
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