cascade_feeddown/Pythia/main131.cc

0001 #include <iostream>
0002 #include <cstdlib>
0003 #include "Pythia8/Pythia.h"
0004
0005 #ifndef HEPMC2
0006 #include "Pythia8Plugins/HepMC3.h"
0007 #else
0008 #include "Pythia8Plugins/HepMC2.h"
0009 #endif
0010
0011 using namespace Pythia8;
0012
0013 //==========================================================================
0014
0015 int main(int argc, char* argv[]) {
0016
0017   // Defaults
0018   std::string outputFile = "main131.hepmc";
0019   int nEvents = 500000;
0020   int seed = 0; // 0 = time-based seed in Pythia
0021
0022   // Parse command-line arguments
0023   if (argc > 1) {
0024     outputFile = argv[1];
0025   }
0026   if (argc > 2) {
0027     nEvents = std::atoi(argv[2]);
0028     if (nEvents <= 0) {
0029       std::cerr << "Error: number of events must be positive\n";
0030       return 1;
0031     }
0032   }
0033   if (argc > 3) {
0034     seed = std::atoi(argv[3]);
0035     if (seed < 0) {
0036       std::cerr << "Error: seed must be >= 0\n";
0037       return 1;
0038     }
0039   }
0040   if (argc > 4) {
0041     std::cerr << "Usage: " << argv[0]
0042               << " [output.hepmc] [nEvents] [seed]\n";
0043     return 1;
0044   }
0045
0046   std::cout << "Writing HepMC output to: " << outputFile << "\n";
0047   std::cout << "Number of events: " << nEvents << "\n";
0048   std::cout << "Random seed: " << seed << "\n";
0049
0050   // Interface for conversion from Pythia8::Event to HepMC event
0051   Pythia8ToHepMC toHepMC(outputFile);
0052
0053   // Generator
0054   Pythia pythia;
0055
0056   pythia.readString("Random:setSeed = on");
0057   pythia.readString("Random:seed = " + std::to_string(seed));
0058
0059   // Change the following line to use a different steering card if desired
0060   pythia.readFile("/sphenix/user/hjheng/sPHENIXRepo/analysis/LightFlavorRatios/macros/simulation/steeringCards/phpythia8_minBias_Detroit.cfg");
0061
0062   // Initialize
0063   if (!pythia.init()) return 1;
0064
0065   // Event loop
0066   for (int iEvent = 0; iEvent < nEvents; ++iEvent) {
0067     if (!pythia.next()) continue;
0068     toHepMC.writeNextEvent(pythia);
0069   }
0070
0071   // Statistics
0072   pythia.stat();
0073
0074   return 0;
0075 }