1 | ////////////////////////////////////////////////////////////////////////// |
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2 | // Matt.Dobbs@Cern.CH, December 1999 |
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3 | // November 2000, updated to use Pythia 6.1 |
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4 | // example of generating events with Pythia |
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5 | // using HepMC/PythiaWrapper.h |
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6 | // Events are read into the HepMC event record from the FORTRAN HEPEVT |
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7 | // common block using the IO_HEPEVT strategy -- nothing is done with them. |
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8 | // This program is just used to find the total time required to transfer |
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9 | // from HEPEVT into the HepMC event record. |
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10 | ////////////////////////////////////////////////////////////////////////// |
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11 | // To Compile: go to the HepMC directory and type: |
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12 | // gmake examples/example_MyPythiaOnlyTo HepMC.exe |
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13 | // |
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14 | // See comments in examples/example_MyPythia.cxx regarding the HEPEVT wrapper. |
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15 | // |
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16 | |
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17 | #include <iostream> |
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18 | #include "HepMC/PythiaWrapper.h" |
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19 | #include "HepMC/IO_HEPEVT.h" |
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20 | #include "HepMC/GenEvent.h" |
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21 | #include "PythiaHelper.h" |
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22 | |
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23 | int main() { |
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24 | // |
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25 | //........................................HEPEVT |
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26 | // Pythia 6.1 uses HEPEVT with 4000 entries and 8-byte floating point |
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27 | // numbers. We need to explicitly pass this information to the |
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28 | // HEPEVT_Wrapper. |
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29 | // |
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30 | HepMC::HEPEVT_Wrapper::set_max_number_entries(4000); |
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31 | HepMC::HEPEVT_Wrapper::set_sizeof_real(8); |
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32 | // |
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33 | //........................................PYTHIA INITIALIZATIONS |
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34 | initPythia(); |
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35 | // |
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36 | //........................................HepMC INITIALIZATIONS |
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37 | // |
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38 | // Instantiate an IO strategy for reading from HEPEVT. |
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39 | HepMC::IO_HEPEVT hepevtio; |
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40 | // |
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41 | //........................................EVENT LOOP |
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42 | for ( int i = 1; i <= 100; i++ ) { |
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43 | if ( i%50==1 ) std::cout << "Processing Event Number " |
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44 | << i << std::endl; |
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45 | call_pyevnt(); // generate one event with Pythia |
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46 | // pythia pyhepc routine convert common PYJETS in common HEPEVT |
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47 | call_pyhepc( 1 ); |
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48 | HepMC::GenEvent* evt = hepevtio.read_next_event(); |
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49 | // define the units (Pythia uses GeV and mm) |
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50 | evt->use_units(HepMC::Units::GEV, HepMC::Units::MM); |
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51 | // set number of multi parton interactions |
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52 | evt->set_mpi( pypars.msti[31-1] ); |
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53 | // set cross section information |
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54 | evt->set_cross_section( HepMC::getPythiaCrossSection() ); |
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55 | // |
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56 | //.......................USER WOULD PROCESS EVENT HERE |
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57 | // |
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58 | // we also need to delete the created event from memory |
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59 | delete evt; |
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60 | } |
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61 | //........................................TERMINATION |
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62 | // write out some information from Pythia to the screen |
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63 | call_pystat( 1 ); |
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64 | |
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65 | return 0; |
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66 | } |
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67 | |
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68 | |
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69 | |
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