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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