Re: TH1 as TTree branch??

From: William J Deninger (deninger@uiuc.edu)
Date: Fri Apr 10 1998 - 03:42:29 MEST 

Rene,
How is one able to view via the TBrowser the "sum" of all histograms stored
in a tree tree. Is it even possible?

Thanks again, William

//______________________
// incorrect attempt
//______________________
{
// open root file
 TFile f= new TFile("test.root", "recreate");
 f->SetCompressionLevel(1);

// create canvas.. for viewing stuff
 TCanvas *c1 = new TCanvas("c1","canvas");
 c1->cd();

// create tree
 TTree *tree = new TTree("tree","test");
 tree->SetAutoSave(64000000); // 64MB autosave

// create event tree branch
 TSimple *simple = new TSimple;
 TH1F *hist = new TH1F("hist","test histogram",100,0,100);
 simple->hist = hist;

 tree->Branch("simple","TSimple",&simple,16000,1);

// loop filling tree with 100 items
 Int_t i;
 for (i=0; i<100; i++) { hist->Fill( (Float_t) i); tree->Fill(); }

// create browser
 bb = new TBrowser;
 tree->Draw("hist");
}

//______________________
class Show : public TObject
{
...
TH1F *hist;
}

-----Original Message-----
From: Rene Brun <Rene.Brun@cern.ch>
To: William J Deninger <deninger@uiuc.edu>
Cc: Rene Brun <brun@hpbrun.cern.ch>; roottalk <roottalk@hpsalo.cern.ch>
Date: Monday, April 06, 1998 1:46 AM
Subject: Re: TH1 as TTree branch??


>William J Deninger wrote:
>>
>> Does this also apply to classes inheriting TH1F?  (Further modification
of
>> my analysis code has brought about this question)
>>
>> William Deninger
>>
>> >
>> >> Hello,
>> >>
>> >> Is it possible to have a TH1F histogram as a data member  in a TTree
>> branch?  I remember reading something about this, but I wasn't able to
find
>> it in root talk previous.
>
>a TH1F object is a TObject.
>Any TObject can be a branch. Example of a class with several TObject
>
>class Show : public TObject {
> TNamed    *fNamed;
> TH1F      *fH1;
> TList     *fArrayofPulses;
> TObjArray *fSomeArrayofObjects;
>
>
>Rene Brun
>

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