Re: [ROOT] TTree::UnbinnedFit in 3.00-06

From: Rene Brun (Rene.Brun@cern.ch)
Date: Wed Apr 18 2001 - 16:04:48 MEST


Hi Chris,

Thanks for reporting this problem with UnbinnedFit.

The fix is now in the development version 3.01 in CVS.

Rene Brun

Chris Roat wrote:
> 
> Hi ROOTers,
> 
> Does anyone have a working example of TTree::UnbinnedFit in ROOT 3.00-06.
> I have gotten TTree::UnbinnedFit to work in 2.25-03, but not yet in
> 3.00-06.  I get a seg fault at the call to the UnbinnedFit method.
> 
> Below are the 2 macros I use - one to generate a ntuple of random numbers,
> and one to try and fit it.  If this works for others, perhaps there is
> something the matter with my setup?
> 
> Chris
> 
> // for ntuple generation
> 
> void
> example() {
> 
>   gROOT->Reset();
>   TFile *hfile = gROOT->FindObject("hsimple.root");
>   if (hfile) hfile->Close();
>   hfile = new TFile("hsimple.root","RECREATE","Random Root File");
>   ntuple = new TNtuple("ntuple","Random ntuple","px:i");
> 
>   gRandom->SetSeed();
>   Float_t px,py;
> 
>   for ( Int_t i=0; i<25000; i++) {
>     gRandom->Rannor(px,py);
>     ntuple->Fill(px,i);
>   }
>   hfile->Write();
> }
> 
> // for fitting
> void
> example2() {
> 
>   TFile *f = gROOT->FindObject("hsimple.root");
>   if (!f) f= new TFile("hsimple.root");
>   TTree *tree= (TTree*)f.Get("ntuple");
> 
>   TF1* f1 = new TF1("f1", "gaus(0)/sqrt(2*3.14159)/[2]", 0, 5);
>   f1->SetParameters(1.0, 0.2, 0.3);
>   f1->SetParLimits(0, 1, 1); // for correct normalization
> 
>   tree->Draw("px");
>   tree->UnbinnedFit("f1", "px" );
> }



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