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Reference Guide
circular.C
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1/// \file
2/// \ingroup tutorial_tree
3/// \notebook -nodraw
4/// Example of a circular Tree
5///
6/// Circular Trees are interesting in online real time environments
7/// to store the results of the last maxEntries events.
8/// for more info, see TTree::SetCircular.
9/// Circular trees must be memory resident.
10///
11/// \macro_code
12///
13/// \author Rene Brun
14
15void circular() {
16 auto T = new TTree("T","test circular buffers");
17 TRandom r;
18 Float_t px,py,pz;
19 Double_t randomNum;
20 UShort_t i;
21 T->Branch("px",&px,"px/F");
22 T->Branch("py",&py,"px/F");
23 T->Branch("pz",&pz,"px/F");
24 T->Branch("random",&randomNum,"random/D");
25 T->Branch("i",&i,"i/s");
26 T->SetCircular(20000); //keep a maximum of 20000 entries in memory
27 for (i = 0; i < 65000; i++) {
28 r.Rannor(px,py);
29 pz = px*px + py*py;
30 randomNum = r.Rndm();
31 T->Fill();
32 }
33 T->Print();
34}
35
unsigned short UShort_t
Definition: RtypesCore.h:40
float Float_t
Definition: RtypesCore.h:57
double Double_t
Definition: RtypesCore.h:59
Option_t Option_t TPoint TPoint const char GetTextMagnitude GetFillStyle GetLineColor GetLineWidth GetMarkerStyle GetTextAlign GetTextColor GetTextSize void char Point_t Rectangle_t WindowAttributes_t Float_t r
This is the base class for the ROOT Random number generators.
Definition: TRandom.h:27
A TTree represents a columnar dataset.
Definition: TTree.h:79
double T(double x)
Definition: ChebyshevPol.h:34