eic-smear  1.0.3
A collection of ROOT classes for Monte Carlo events and a fast-smearing code simulating detector effects for the Electron-Ion Collider task force
draw.cxx
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1 //
2 // draw.cxx
3 //
4 // Created by TB on 6/13/11.
5 // Copyright 2011 BNL. All rights reserved.
6 //
7 // Example of a simple analysis using TTree::Draw() statements.
8 
9 void draw(const TString inputFile ) {
10 
11  // When you use only TTree::Draw() you can ignore errors like these:
12  //Warning in <TClass::TClass>: no dictionary for class EventBase is available
13  //Warning in <TClass::TClass>: no dictionary for class Particle is available
14  // ROOT doesn't need the listed dictionary files to access the data.
15  TFile file(inputFile, "READ");
16 
17  // The TTree is named EICTree
18  TTree* tree(NULL );
19  file.GetObject("EICTree", tree );
20  if(! tree) return; // Oops!
21 
22  TCanvas* canvas = new TCanvas;
23  canvas->Divide(2, 1);
24 
25  canvas->cd(1);
26  // For event-wise quantities you don't need to prepend "event." to the
27  // Draw() statement string; ROOT will automatically resolve it:
28  tree->Draw("QSquared"); // Equivalent to "event.QSquared"
29 
30  canvas->cd(2);
31  // Similarly you don't need to prepend "event.particles." to access particle
32  // variables.
33  tree->Draw("pt"); // Equivalent to "event.particles.pt".
34 }
tree
Definition: tree.py:1
draw
void draw(const TString inputFile)
Definition: draw.cxx:9