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 +
+-----------------------------------------------------------------+
This archive was generated by hypermail 2b29 : Sat Jan 04 2003 - 23:51:18 MET