Re: [ROOT] About fit with my function

From: Pasha Murat (630)840-8237 FNAL (630)859-3463 home (murat@murat.fnal.gov)
Date: Sat Feb 17 2001 - 17:03:19 MET


hi - you may want to check if `hsimple.root' exists in the current directory.
`fitexample' assumes that it exists and tries to open it ...

							best, Pasha

babintsev@mx.ihep.su wrote:
> 
>       babintsev@mx.ihep.su, 17-FEB-2001
> 
> Hello rooters.
> 
> What does it mean: I take script from tutorials (below):
> and have the following result (Root  Version   2.25/03)
> 
> root [1] .x fitexample.C
> 
>  *** Break *** floating point exception
> Root > Function fitf() busy flag cleared
> Function fitexample() busy flag cleared
> 
>    //_____________________macro fitexample.C___________________________
>    Double_t fitf(Double_t *x, Double_t *par)
>    {
>       Double_t arg = 0;
>       if (par[2]) arg = (x[0] - par[1])/par[2];
> 
>       Double_t fitval = par[0]*TMath::Exp(-0.5*arg*arg);
>       return fitval;
>    }
>    void fitexample()
>    {
>       TFile *f = new TFile("hsimple.root");
> 
>       TH1F *hpx = (TH1F*)f->Get("hpx");
> 
>       TF1 *func = new TF1("fit",fitf,-3,3,3);
>       func->SetParameters(500,hpx->GetMean(),hpx->GetRMS());
>       func->SetParNames("Constant","Mean_value","Sigma");
>       hpx->Fit("fit");
>    }
> -------end of script---------------------
> 
> Thanks a lot.
> 
>                                    Volodja Babintsev



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