RE: AddBinContent

Because, TH2 are often used to draw a pad frame, the TH2 Paint functions with options like "colz", "cont" return immediately once the axes are drawn if the number of entries is null. There is no need to loop on the cell contents. If one use SetBinContent to fill an histogram, the number of entries is not incremented. Only the Fill functions increment the number of entries. In that case, the simplest is to add one statement before drawing the histogram:  

 h->SetEntries(1);

-----Original Message-----
From: owner-roottalk_at_root.cern.ch [mailto:owner-roottalk_at_root.cern.ch] On Behalf Of Nicolas Produit
Sent: Thursday, December 13, 2007 12:21 PM To: roottalk
Subject: [ROOT] AddBinContent

Hi,

I fill a 2D histogram in using in a loop the method h->AddBinContent(p,s)

The histogram does not show properly if doing: h->Draw()
or
h->Draw("COLZ")
(show blank as it was 0 entry everywhere) but it is displaying correctely when doing: h->Draw("LEGO")

h->GetEntries()
return 0 Entries
but the statistical box has non zero entries everywhere

doing a
h->SetEntries(nn)
where nn is the number of time the AddBinContent was called make the histogram behaving correctely for ->Draw() and ->Draw("COLZ")

root version 5.08/00

Thanks

---
Nicolas Produit
INTEGRAL Science Data Center  Phone:  +41 22 379 2140
16, Chemin d'Ecogia                            Fax:  +41 22 379 2133
CH-1290 Versoix                               www:
http://isdc.unige.ch/~produit