Re: Problem in the number of entries

Saleem,

Maybe submit a running example .

Anyhow, what are you trying to accomplish :

• divide two histograms : that is already implemented in the histogram class
• you calculate h1->GetNbinsX() times the sum of h2 instead of once: take the inner loop out
• the final error is sqrt(e) : what kind of statistics is that ?

Eddy

• "Saleem, Muhammad" <saleem_at_slac.stanford.edu> wrote:

>
> Hi,
>
> I take the ratio of 2 histograms using the following as pasted below:
>
> This show me Entries:16 in the stat box.
>
> For sure I can count that I have several (100's) entries there.
>
> Any trick or tip !
>
> TH1F *h1 = new TH1F("h1", "h1", 16, 0, 16);
> TH1F *h2 = new TH1F("h2", "h2", 16, 0, 16);
> TH1F *ratio1 = new TH1F("ratio1", "ratio1", 16, 0, 16);
>
> for (int i=1 ; i<=h1->GetNbinsX() ; i++ ) {
>
> double u = 0;
>
> for (int j=1 ; j<=h2->GetNbinsX() ; j++ ) {
>
> u += h2->GetBinContent(j);
> }
>
> double t = h1->GetBinContent(i);
>
> double e = 0; double Er = 0;
>
> if (t!=0) {
> e = u/t;
> Er = TMath::Sqrt(e);
>
> }
>
> ratio2->SetBinContent(i, e);
> ratio2->SetBinError(i, (Er));
> }
>
> regards,
>
> ---saleem
>
>
Received on Tue Nov 27 2007 - 02:57:03 CET