[807] | 1 | // |
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| 2 | // ******************************************************************** |
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| 3 | // * License and Disclaimer * |
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| 4 | // * * |
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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| 7 | // * conditions of the Geant4 Software License, included in the file * |
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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| 9 | // * include a list of copyright holders. * |
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| 10 | // * * |
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| 11 | // * Neither the authors of this software system, nor their employing * |
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| 12 | // * institutes,nor the agencies providing financial support for this * |
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| 13 | // * work make any representation or warranty, express or implied, * |
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| 14 | // * regarding this software system or assume any liability for its * |
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| 15 | // * use. Please see the license in the file LICENSE and URL above * |
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| 16 | // * for the full disclaimer and the limitation of liability. * |
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| 17 | // * * |
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| 18 | // * This code implementation is the result of the scientific and * |
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| 19 | // * technical work of the GEANT4 collaboration. * |
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| 20 | // * By using, copying, modifying or distributing the software (or * |
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| 21 | // * any work based on the software) you agree to acknowledge its * |
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| 22 | // * use in resulting scientific publications, and indicate your * |
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| 23 | // * acceptance of all terms of the Geant4 Software license. * |
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| 24 | // ******************************************************************** |
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| 25 | // |
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| 26 | // |
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| 27 | ////////////////////////////////////////////////////////////////////////// |
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| 28 | // Matt.Dobbs@Cern.CH, December 1999 |
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| 29 | // November 2000, updated to use Pythia 6.1 |
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| 30 | // example of generating events with Pythia |
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| 31 | // using HepMC/PythiaWrapper.h |
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| 32 | // Events are read into the HepMC event record from the FORTRAN HEPEVT |
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| 33 | // common block using the IO_HEPEVT strategy and then output to file in |
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| 34 | // ascii format using the IO_Ascii strategy. |
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| 35 | ////////////////////////////////////////////////////////////////////////// |
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| 36 | // To Compile: go to the HepMC directory and type: |
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| 37 | // gmake examples/example_MyPythia.exe |
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| 38 | // |
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| 39 | // In this example the precision and number of entries for the HEPEVT |
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| 40 | // fortran common block are explicitly defined to correspond to those |
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| 41 | // used in the Pythia version of the HEPEVT common block. |
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| 42 | // |
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| 43 | // If you get funny output from HEPEVT in your own code, probably you have |
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| 44 | // set these values incorrectly! |
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| 45 | // |
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| 46 | |
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| 47 | #include <iostream> |
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| 48 | #include "HepMC/PythiaWrapper.h" |
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| 49 | #include "HepMC/IO_HEPEVT.h" |
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| 50 | #include "HepMC/IO_Ascii.h" |
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| 51 | #include "HepMC/GenEvent.h" |
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| 52 | |
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| 53 | int main() { |
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| 54 | // |
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| 55 | //........................................HEPEVT |
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| 56 | // Pythia 6.1 uses HEPEVT with 4000 entries and 8-byte floating point |
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| 57 | // numbers. We need to explicitly pass this information to the |
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| 58 | // HEPEVT_Wrapper. |
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| 59 | // |
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| 60 | HepMC::HEPEVT_Wrapper::set_max_number_entries(4000); |
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| 61 | HepMC::HEPEVT_Wrapper::set_sizeof_real(8); |
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| 62 | // |
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| 63 | //........................................PYTHIA INITIALIZATIONS |
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| 64 | // (Some platforms may require the initialization of pythia PYDATA block |
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| 65 | // data as external - if you get pythia initialization errors try |
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| 66 | // commenting in/out the below call to initpydata() ) |
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| 67 | // initpydata(); |
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| 68 | // |
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| 69 | // Select W+gamma process (process number 20) |
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| 70 | // (here we have to be careful of C/F77 differences: arrays in C |
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| 71 | // start at 0, F77 at 1, so we need to subtract 1 from the process #) |
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| 72 | pysubs.msel=0; |
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| 73 | pysubs.msub[20-1] = 1; |
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| 74 | // set random number seed (mandatory!) |
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| 75 | pydatr.mrpy[0]=55122 ; |
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| 76 | // Tell Pythia not to write multiple copies of particles in event record. |
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| 77 | pypars.mstp[128-1] = 2; |
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| 78 | // Example of setting a Pythia parameter: set the top mass |
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| 79 | pydat2.pmas[1-1][6-1]= 175; |
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| 80 | // |
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| 81 | // Call pythia initialization |
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| 82 | call_pyinit( "CMS", "p", "p", 14000. ); |
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| 83 | |
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| 84 | //........................................HepMC INITIALIZATIONS |
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| 85 | // |
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| 86 | // Instantiate an IO strategy for reading from HEPEVT. |
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| 87 | HepMC::IO_HEPEVT hepevtio; |
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| 88 | // |
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| 89 | // Instantial an IO strategy to write the data to file - it uses the |
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| 90 | // same ParticleDataTable |
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| 91 | HepMC::IO_Ascii ascii_io("example_MyPythia.dat",std::ios::out); |
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| 92 | // |
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| 93 | //........................................EVENT LOOP |
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| 94 | for ( int i = 1; i <= 10; i++ ) { |
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| 95 | if ( i%50==1 ) std::cout << "Processing Event Number " |
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| 96 | << i << std::endl; |
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| 97 | call_pyevnt(); // generate one event with Pythia |
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| 98 | // pythia pyhepc routine converts common PYJETS in common HEPEVT |
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| 99 | call_pyhepc( 1 ); |
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| 100 | HepMC::GenEvent* evt = hepevtio.read_next_event(); |
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| 101 | // add some information to the event |
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| 102 | evt->set_event_number(i); |
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| 103 | evt->set_signal_process_id(20); |
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| 104 | // write the event out to the ascii file |
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| 105 | ascii_io << evt; |
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| 106 | // we also need to delete the created event from memory |
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| 107 | delete evt; |
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| 108 | } |
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| 109 | //........................................TERMINATION |
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| 110 | // write out some information from Pythia to the screen |
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| 111 | call_pystat( 1 ); |
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| 112 | |
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| 113 | return 0; |
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| 114 | } |
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| 115 | |
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| 116 | |
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| 117 | |
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