Re: [ROOT] E-option and FitSlices

From: Rene Brun (Rene.Brun@cern.ch)
Date: Mon Nov 18 2002 - 18:03:53 MET


Hi Dariusz,

I am away until Wednesday afternoon. I will investigate
this problem as soon as I will be back.

Rene Brun

On Mon, 18 Nov 2002, Dariusz Miskowiec wrote:

> Dear Root experts,
> 
> I have the impression that performing a fit with option "E" 
> affects not only the actual fit but also all fits which come 
> after it. Particularly, FitSlices starts producing unreasonably 
> small error bars for the second parameter. This is shown in 
> 
> http://www-linux.gsi.de/~misko/eoption.gif 
> 
> which was produced with root 3.03/09 under debian linux using 
> enclosed macro. Many thanks and best regards
> 
> Dariusz Miskowiec
> 
> {
> gROOT->Reset();
> gStyle->SetPalette(1,0);
> 
> TF1 *ga1 = new TF1("ga1","gaus",-4,4);
> TF2 *ga2 = new TF2("ga2","exp(-(y-200)*(y-200)/2/50/50)",-4,4,0,500);
> ga1->SetParameters(100.0,0.0,1.0);
> ga1->SetLineColor(2);
> 
> TH1F *his1 = new TH1F("his1","one dim",100,-4,4);
> TH2F *his2 = new TH2F("his2","two dim",48,-4,4,50,0,500);
> his1->FillRandom("ga1",1000);
> his2->FillRandom("ga2",10000);
> 
> TCanvas *c1 = new TCanvas("c1","E-option problem",10,10,500,400);
> c1->Divide(3,2);
>  
> c1->cd(1); his1->Fit("ga1");
> c1->cd(2); his2->FitSlicesY();
> c1->cd(2); his2->Draw("colz"); gROOT->Get("his2_1")->Draw("same");
> c1->cd(3); gROOT->Get("his2_2")->Draw();
> 
> c1->cd(4); his1->Fit("ga1","E");
> c1->cd(5); his2->FitSlicesY();
> c1->cd(5); his2->Draw("colz"); gROOT->Get("his2_1")->Draw("same");
> c1->cd(6); gROOT->Get("his2_2")->Draw();
> }
> 
> 
> 
> -- 
> +-----------------------------------------------------------------+
> +  Dariusz Miskowiec                  E-mail: D.Miskowiec@gsi.de  +
> +  GSI, Planckstr. 1                  Phone:  0049-6159-712-133   +
> +  D-64291 Darmstadt                  Fax:    0049-6159-712-989   +
> +-----------------------------------------------------------------+
> 



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