mathcoreVectorFloatIO.C File Reference

Detailed Description

Macro illustrating I/O with Lorentz Vectors of floats The dictionary for LorentzVector of float is not in the libMathCore, therefore is generated when parsed the file with CINT.

To run this macro you must do

root[0] .L  mathcoreVectorFloatIO.C+
root[1] runIt();

#include "TRandom.h"
#include "TStopwatch.h"
#include "TSystem.h"
#include "TFile.h"
#include "TTree.h"
#include "TH1D.h"
#include "TCanvas.h"

#include <iostream>

#include "TLorentzVector.h"

#include "Math/Vector4D.h"


// Now the dictionary contains the vector's with float types
// No need to force dictionary generation
// You need to run ACLIC with old ROOT version
// and uncomment these lines below 
// #ifdef __MAKECINT__
// #pragma link C++ class ROOT::Math::PxPyPzE4D<float>+;
// #pragma link C++ class ROOT::Math::LorentzVector<ROOT::Math::PxPyPzE4D<float> >+;
// #pragma link C++ typedef ROOT::Math::XYZTVectorF;
// #endif

using namespace ROOT::Math;

void write(int n) {

   TRandom R;
   TStopwatch timer;

   TFile f1("mathcoreVectorIO_F.root","RECREATE");

   // create tree
   TTree t1("t1","Tree with new Float LorentzVector");

   XYZTVectorF *v1 = new XYZTVectorF();
   t1.Branch("LV branch","ROOT::Math::XYZTVectorF",&v1);

   timer.Start();
   for (int i = 0; i < n; ++i) {
      double Px = R.Gaus(0,10);
      double Py = R.Gaus(0,10);
      double Pz = R.Gaus(0,10);
      double E  = R.Gaus(100,10);
      v1->SetCoordinates(Px,Py,Pz,E);
      t1.Fill();
   }

   f1.Write();
   timer.Stop();
   std::cout << " Time for new Float Vector " << timer.RealTime() << "  " << timer.CpuTime() << std::endl;
   t1.Print();
}

void read() {

   TRandom R;
   TStopwatch timer;

   TFile f1("mathcoreVectorIO_F.root");

   // create tree
   TTree *t1 = (TTree*)f1.Get("t1");

   XYZTVectorF *v1 = 0;
   t1->SetBranchAddress("LV branch",&v1);

   timer.Start();
   int n = (int) t1->GetEntries();
   std::cout << " Tree Entries " << n << std::endl;
   double etot=0;
   for (int i = 0; i < n; ++i) {
      t1->GetEntry(i);
      etot += v1->E();
   }

   timer.Stop();
   std::cout << " Time for new Float Vector " << timer.RealTime() << "  " << timer.CpuTime() << std::endl;
   std::cout << " E average" << n<< "  " << etot << "  " << etot/double(n) << endl;
}

void runIt() {

#if defined(__CINT__) && !defined(__MAKECINT__)
   gSystem->Load("libMathCore");
   gSystem->Load("libPhysics");
   using namespace ROOT::Math ;

   cout << "This tutorial can run only using ACliC, you must run it by doing: " << endl;
   cout << "\t  .L tutorials/math/mathcoreVectorFloatIO.C+" << endl;
   cout << "\t  runIt()" << endl;
#endif
   int nEvents = 100000;
   write(nEvents);
   read();
}

void mathcoreVectorFloatIO() {
#if defined(__CINT__) && !defined(__MAKECINT__)
   gSystem->Load("libMathCore");
   gSystem->Load("libPhysics");
   using namespace ROOT::Math ;

   cout << "This tutorial can run only using ACliC, you must run it by doing: " << endl;
   cout << "\t  .L tutorials/math/mathcoreVectorFloatIO.C+" << endl;
   cout << "\t  runIt()" << endl;

#endif
}

Author

Lorenzo Moneta

Definition in file mathcoreVectorFloatIO.C.