[1] | 1 | // main61.cc is a part of the PYTHIA event generator. |
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| 2 | // Copyright (C) 2012 Mikhail Kirsanov, Torbjorn Sjostrand. |
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| 3 | // PYTHIA is licenced under the GNU GPL version 2, see COPYING for details. |
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| 4 | // Please respect the MCnet Guidelines, see GUIDELINES for details. |
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| 5 | |
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| 6 | // This is a simple test program. |
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| 7 | // It illustrates how a file with HepMC events can be generated by Pythia8. |
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| 8 | // It is identical with main42, except that it is compiled with LHAPDF. |
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| 9 | // Input and output files are specified on the command line, e.g. like |
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| 10 | // ./main61.exe main61.cmnd hepmcout61.dat > out |
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| 11 | // The main program contains no analysis; this is intended to happen later. |
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| 12 | // It therefore "never" has to be recompiled to handle different tasks. |
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| 13 | |
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| 14 | // WARNING: typically one needs 25 MB/100 events at the LHC. |
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| 15 | // Therefore large event samples may be impractical. |
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| 16 | |
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| 17 | #include "Pythia.h" |
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| 18 | #include "HepMCInterface.h" |
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| 19 | |
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| 20 | #include "HepMC/GenEvent.h" |
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| 21 | #include "HepMC/IO_GenEvent.h" |
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| 22 | |
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| 23 | // Following line is a deprecated alternative, removed in recent versions. |
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| 24 | //#include "HepMC/IO_Ascii.h" |
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| 25 | //#include "HepMC/IO_AsciiParticles.h" |
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| 26 | |
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| 27 | // Following line to be used with HepMC 2.04 onwards. |
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| 28 | #ifdef HEPMC_HAS_UNITS |
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| 29 | #include "HepMC/Units.h" |
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| 30 | #endif |
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| 31 | |
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| 32 | using namespace Pythia8; |
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| 33 | |
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| 34 | int main(int argc, char* argv[]) { |
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| 35 | |
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| 36 | // Check that correct number of command-line arguments |
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| 37 | if (argc != 3) { |
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| 38 | cerr << " Unexpected number of command-line arguments. \n You are" |
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| 39 | << " expected to provide one input and one output file name. \n" |
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| 40 | << " Program stopped! " << endl; |
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| 41 | return 1; |
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| 42 | } |
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| 43 | |
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| 44 | // Check that the provided input name corresponds to an existing file. |
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| 45 | ifstream is(argv[1]); |
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| 46 | if (!is) { |
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| 47 | cerr << " Command-line file " << argv[1] << " was not found. \n" |
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| 48 | << " Program stopped! " << endl; |
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| 49 | return 1; |
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| 50 | } |
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| 51 | |
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| 52 | // Confirm that external files will be used for input and output. |
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| 53 | cout << "\n >>> PYTHIA settings will be read from file " << argv[1] |
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| 54 | << " <<< \n >>> HepMC events will be written to file " |
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| 55 | << argv[2] << " <<< \n" << endl; |
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| 56 | |
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| 57 | // Interface for conversion from Pythia8::Event to HepMC one. |
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| 58 | HepMC::I_Pythia8 ToHepMC; |
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| 59 | // ToHepMC.set_crash_on_problem(); |
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| 60 | |
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| 61 | // Specify file where HepMC events will be stored. |
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| 62 | HepMC::IO_GenEvent ascii_io(argv[2], std::ios::out); |
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| 63 | // Following line is a deprecated alternative, removed in recent versions |
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| 64 | // HepMC::IO_Ascii ascii_io("hepmcout32.dat", std::ios::out); |
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| 65 | // Line below is an eye-readable one-way output, uncomment the include above |
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| 66 | // HepMC::IO_AsciiParticles ascii_io("hepmcout32.dat", std::ios::out); |
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| 67 | |
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| 68 | // Generator. |
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| 69 | Pythia pythia; |
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| 70 | |
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| 71 | // Read in commands from external file. |
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| 72 | pythia.readFile(argv[1]); |
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| 73 | |
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| 74 | // Extract settings to be used in the main program. |
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| 75 | int nEvent = pythia.mode("Main:numberOfEvents"); |
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| 76 | int nAbort = pythia.mode("Main:timesAllowErrors"); |
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| 77 | |
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| 78 | // Initialization. |
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| 79 | pythia.init(); |
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| 80 | |
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| 81 | // Begin event loop. |
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| 82 | int iAbort = 0; |
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| 83 | for (int iEvent = 0; iEvent < nEvent; ++iEvent) { |
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| 84 | |
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| 85 | // Generate event. |
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| 86 | if (!pythia.next()) { |
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| 87 | |
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| 88 | // If failure because reached end of file then exit event loop. |
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| 89 | if (pythia.info.atEndOfFile()) { |
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| 90 | cout << " Aborted since reached end of Les Houches Event File\n"; |
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| 91 | break; |
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| 92 | } |
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| 93 | |
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| 94 | // First few failures write off as "acceptable" errors, then quit. |
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| 95 | if (++iAbort < nAbort) continue; |
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| 96 | cout << " Event generation aborted prematurely, owing to error!\n"; |
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| 97 | break; |
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| 98 | } |
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| 99 | |
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| 100 | // Construct new empty HepMC event. |
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| 101 | #ifdef HEPMC_HAS_UNITS |
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| 102 | // This form with arguments is only meaningful for HepMC 2.04 onwards, |
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| 103 | // and even then unnecessary if HepMC was built with GeV and mm as units. |
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| 104 | HepMC::GenEvent* hepmcevt = new HepMC::GenEvent( |
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| 105 | HepMC::Units::GEV, HepMC::Units::MM); |
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| 106 | #else |
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| 107 | // This form is needed for backwards compatibility. |
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| 108 | // In HepMCInterface.cc a conversion from GeV to MeV will be done. |
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| 109 | HepMC::GenEvent* hepmcevt = new HepMC::GenEvent(); |
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| 110 | #endif |
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| 111 | |
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| 112 | // Fill HepMC event, including PDF info. |
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| 113 | ToHepMC.fill_next_event( pythia, hepmcevt ); |
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| 114 | // This alternative older method fills event, without PDF info. |
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| 115 | // ToHepMC.fill_next_event( pythia.event, hepmcevt ); |
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| 116 | |
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| 117 | // Write the HepMC event to file. Done with it. |
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| 118 | ascii_io << hepmcevt; |
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| 119 | delete hepmcevt; |
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| 120 | |
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| 121 | // End of event loop. Statistics. |
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| 122 | } |
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| 123 | pythia.stat(); |
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| 124 | |
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| 125 | // Done. |
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| 126 | return 0; |
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| 127 | } |
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