Subversion Repositories hepmc

//////////////////////////////////////////////////////////////////////////
// Matt.Dobbs@Cern.CH, December 1999
// November 2000, updated to use Pythia 6.1
// example of generating events with Pythia
// using HepMC/PythiaWrapper.h
// Events are read into the HepMC event record from the FORTRAN HEPEVT
// common block using the IO_HEPEVT strategy -- nothing is done with them.
// This program is just used to find the total time required to transfer
// from HEPEVT into the HepMC event record.
//////////////////////////////////////////////////////////////////////////
// To Compile: go to the HepMC directory and type:
// gmake examples/example_MyPythiaOnlyTo HepMC.exe
//
// See comments in examples/example_MyPythia.cxx regarding the HEPEVT wrapper.
//

#include <iostream>
#include "HepMC/PythiaWrapper.h"
#include "HepMC/IO_HEPEVT.h"
#include "HepMC/GenEvent.h"
#include "PythiaHelper.h"

int main() {    
    //
    //........................................HEPEVT
    // Pythia 6.1 uses HEPEVT with 4000 entries and 8-byte floating point
    //  numbers. We need to explicitly pass this information to the
    //  HEPEVT_Wrapper.
    //
    HepMC::HEPEVT_Wrapper::set_max_number_entries(4000);
    HepMC::HEPEVT_Wrapper::set_sizeof_real(8);
    // 
    //........................................PYTHIA INITIALIZATIONS
    initPythia();
    //
    //........................................HepMC INITIALIZATIONS
    //
    // Instantiate an IO strategy for reading from HEPEVT.
    HepMC::IO_HEPEVT hepevtio;
    //
    //........................................EVENT LOOP
    for ( int i = 1; i <= 100; i++ ) {
        if ( i%50==1 ) std::cout << "Processing Event Number "
                                 << i << std::endl;
        call_pyevnt();      // generate one event with Pythia
        // pythia pyhepc routine convert common PYJETS in common HEPEVT
        call_pyhepc( 1 );
        HepMC::GenEvent* evt = hepevtio.read_next_event();
        // define the units (Pythia uses GeV and mm)
        evt->use_units(HepMC::Units::GEV, HepMC::Units::MM);
        // set number of multi parton interactions
        evt->set_mpi( pypars.msti[31-1] );
        // set cross section information
        evt->set_cross_section( HepMC::getPythiaCrossSection() );
        //
        //.......................USER WOULD PROCESS EVENT HERE
        //
        // we also need to delete the created event from memory
        delete evt;
    }
    //........................................TERMINATION
    // write out some information from Pythia to the screen
    call_pystat( 1 );    

    return 0;
}