tree120_ntuple.C File Reference

Detailed Description

Simple tree analysis.

 
#include "TCanvas.h"
#include "TFile.h"
#include "TNtuple.h"
#include "TProfile.h"
#include "TBenchmark.h"
#include "TStyle.h"
#include "TPaveText.h"
#include "TFrame.h"
#include "TF1.h"
#include "TROOT.h"
#include "TSystem.h"
#include "TInterpreter.h"
 
void tree120_ntuple()
{
   //just in case this script is executed multiple times
   delete gROOT->GetListOfFiles()->FindObject("hsimple.root");
   delete gROOT->GetListOfCanvases()->FindObject("c1");
 
   gBenchmark->Start("ntuple1");
   //
   // Connect ROOT histogram/ntuple demonstration file
   // generated by example $ROOTSYS/tutorials/hsimple.C.
   TString dir = gROOT->GetTutorialDir();
   dir.Append("/hsimple.C");
   dir.ReplaceAll("/./","/");
   if (gBenchmark->GetBench("hsimple") < 0)
      gInterpreter->LoadMacro(dir.Data());
   TFile *f1 = (TFile*)gROOT->ProcessLineFast("hsimple(1)");
   if (!f1)
      return;
   //
   // Create a canvas, with 4 pads
   //
   auto c1 = new TCanvas("c1","The Ntuple canvas",200,10,700,780);
   auto pad1 = new TPad("pad1","This is pad1",0.02,0.52,0.48,0.98,21);
   auto pad2 = new TPad("pad2","This is pad2",0.52,0.52,0.98,0.98,21);
   auto pad3 = new TPad("pad3","This is pad3",0.02,0.02,0.48,0.48,21);
   auto pad4 = new TPad("pad4","This is pad4",0.52,0.02,0.98,0.48,1);
   pad1->Draw();
   pad2->Draw();
   pad3->Draw();
   pad4->Draw();
   //
   // Change default style for the statistics box
   gStyle->SetStatW(0.30);
   gStyle->SetStatH(0.20);
   //
   // Display a function of one ntuple column imposing a condition
   // on another column.
   pad1->cd();
   pad1->SetGrid();
   pad1->SetLogy();
   auto ntuple = f1->Get<TNtuple>("ntuple");
   ntuple->SetLineColor(1);
   ntuple->SetFillStyle(1001);
   ntuple->SetFillColor(45);
   ntuple->Draw("3*px+2","px**2+py**2>1");
   ntuple->SetFillColor(38);
   ntuple->Draw("2*px+2","pz>2","same");
   ntuple->SetFillColor(5);
   ntuple->Draw("1.3*px+2","(px^2+py^2>4) && py>0","same");
   pad1->RedrawAxis();
   //
   // Display the profile of two columns
   // The profile histogram produced is saved in the current directory with
   // the name hprofs
   pad2->cd();
   pad2->SetGrid();
   ntuple->Draw("pz:px>>hprofs","","goffprofs");
   TProfile *hprofs = (TProfile*)gDirectory->Get("hprofs");
   hprofs->SetMarkerColor(5);
   hprofs->SetMarkerSize(0.7);
   hprofs->SetMarkerStyle(21);
   hprofs->Fit("pol2");
   // Get pointer to fitted function and modify its attributes
   TF1 *fpol2 = hprofs->GetFunction("pol2");
   fpol2->SetLineWidth(4);
   fpol2->SetLineColor(2);
   //
   // Display a scatter plot of two columns with a selection.
   // Superimpose the result of another cut with a different marker color
   pad3->cd();
   pad3->GetFrame()->SetBorderSize(8);
   ntuple->SetMarkerColor(1);
   ntuple->Draw("py:px","pz>1");
   ntuple->SetMarkerColor(2);
   ntuple->Draw("py:px","pz<1","same");
   //
   // Display a 3-D scatter plot of 3 columns. Superimpose a different selection.
   pad4->cd();
   ntuple->Draw("pz:py:px","(pz<10 && pz>6)+(pz<4 && pz>3)");
   ntuple->SetMarkerColor(4);
   ntuple->Draw("pz:py:px","pz<6 && pz>4","same");
   ntuple->SetMarkerColor(5);
   ntuple->Draw("pz:py:px","pz<4 && pz>3","same");
   auto l4 = new TPaveText(-0.9,0.5,0.9,0.95);
   l4->SetFillColor(42);
   l4->SetTextAlign(12);
   l4->AddText("You can interactively rotate this view in 2 ways:");
   l4->AddText("  - With the RotateCube in clicking in this pad");
   l4->AddText("  - Selecting View with x3d in the View menu");
   l4->Draw();
   //
   c1->cd();
   c1->Update();
   gStyle->SetStatColor(19);
   gBenchmark->Show("ntuple1");
}

Author

Rene Brun

Definition in file tree120_ntuple.C.