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 CLING.
To run this macro you must do
root[0] .L mathcoreVectorFloatIO.C+
root[1] runIt();
Author: Lorenzo Moneta
This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Wednesday, April 17, 2024 at 11:14 AM.
%%cpp -d
#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"
using namespace ROOT::Math;
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
fdef MAKECINT
ragma link C++ class ROOT::Math::PxPyPzE4D
%%cpp -d
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();
}
Definition of a helper function:
%%cpp -d
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;
}
Definition of a helper function:
%%cpp -d
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();
}
#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