HepMC3 event record library
class_example_write.cc

Basic example of use of root I/O: writing events to file

Author
Witold Pokorski
Date
16/10/14
// -*- C++ -*-
//
// This file is part of HepMC
// Copyright (C) 2014-2019 The HepMC collaboration (see AUTHORS for details)
//
/**
* @example class_example_write.cc
* @brief Basic example of use of root I/O: writing events to file
*
* @author Witold Pokorski
* @date 16/10/14
*/
#include "HepMC3/Print.h"
#include "TFile.h"
#include <iostream>
#include <sstream>
using namespace HepMC3;
#include "MyClass.h"
#include "MyRunClass.h"
/** Main */
int main(int argc, char **argv) {
if( argc<3 ) {
std::cout << "Usage: " << argv[0] << " <input_hepmc3_file> <output_root_file>" <<std:: endl;
exit(-1);
}
ReaderAscii text_input(argv[1]);
TFile* fFile = new TFile(argv[2],"RECREATE");
int events_parsed = 0;
bool is_gen_run_info_written = false;
while( !text_input.failed() ) {
GenEvent evt(Units::GEV,Units::MM);
text_input.read_event(evt);
if( text_input.failed() ) break;
if( events_parsed == 0 ) {
std::cout << "First event: " << std::endl;
}
if(!is_gen_run_info_written) {
if(evt.run_info()) {
GenRunInfo run_info(*evt.run_info());
MyRunClass *my_run = new MyRunClass();
my_run->SetRunInfo(&run_info);
fFile->WriteObject(my_run,"MyRunClass");
is_gen_run_info_written = true;
}
}
MyClass* myclass = new MyClass();
myclass->SetEvent(&evt);
//
std::ostringstream os;
os << events_parsed;
std::string stevt = "Event_" + os.str();
const char* chevt = stevt.c_str();
std::cout << "writing " << stevt << std::endl;
fFile->WriteObject(myclass, chevt);
++events_parsed;
if( events_parsed%100 == 0 ) {
std::cout << "Event: " << events_parsed << std::endl;
}
}
text_input.close();
fFile->Close();
std::cout << "Events parsed and written: " << events_parsed << std::endl;
return 0;
}