Hi,
What is the intended behavior of the Entries field in a histogram when it
is created by dividing two histograms ?
In the following, I take 2 10-bin histograms, one with 6 entries, and one
with 12 entries, and divide them. The integral is what I would expect.
However, the quotient histogram has 23 entries, which doesn't make sense
to me. BTW, I am using root v3_05_04b KCC_4_0 Linux+2.2.
-Ben
{
TH1F *N = new TH1F("N","Numerator",10,0,10);
TH1F *D = new TH1F("D","Denominator",10,0,10);
N->Fill(1);N->Fill(1);N->Fill(1);
D->Fill(1);D->Fill(1);D->Fill(1);D->Fill(1);D->Fill(1);D->Fill(1);
N->Fill(3);N->Fill(3);N->Fill(3);
D->Fill(3);D->Fill(3);D->Fill(3);D->Fill(3);D->Fill(3);D->Fill(3);
N->Sumw2();
D->Sumw2();
TH1F *Q = N->Clone("Q");
Q->SetTitle("Quotient");
Q->Reset();
Q->Divide(N,D,1,1);
Q->Sumw2();
c1 = new TCanvas();
c1->Divide(1,3);
c1->cd(1);
N->Draw();
c1->cd(2);
D->Draw();
c1->cd(3);
Q->Draw();
}
This archive was generated by hypermail 2b29 : Thu Jan 01 2004 - 17:50:16 MET