HepMC3 event record library
pythia8_example.cc
1/**
2 * @example pythia8_example.cc
3 * @brief Basic example of use for pythia8 interface
4 *
5 */
6#include "HepMC3/GenEvent.h"
8#include "HepMC3/Print.h"
9
10#include "Pythia8/Pythia.h"
11#ifdef HEPMC3_USE_INTERFACE_FROM_PYTHIA8
12#include "Pythia8Plugins/HepMC3.h"
13#else
14#include "Pythia8ToHepMC3.h"
15#endif
16#include <iostream>
17using namespace HepMC3;
18
19/** Main program */
20int main(int argc, char **argv) {
21 if (argc < 3) {
22 std::cout << "Usage: " << argv[0] << " <pythia_config_file> <output_hepmc3_file>" << std::endl;
23 exit(-1);
24 }
25
26 Pythia8::Pythia pythia;
27 Pythia8ToHepMC3 pythiaToHepMC;
28 pythia.readFile(argv[1]);
29 pythia.init();
30 std::shared_ptr<GenRunInfo> run = std::make_shared<GenRunInfo>();
31 struct GenRunInfo::ToolInfo generator={std::string("Pythia8"),std::to_string(PYTHIA_VERSION).substr(0,5),std::string("Used generator")};
32 run->tools().push_back(generator);
33 struct GenRunInfo::ToolInfo config={std::string(argv[1]),"1.0",std::string("Control cards")};
34 run->tools().push_back(config);
35 std::vector<std::string> names;
36 for (int iWeight=0; iWeight < pythia.info.nWeights(); ++iWeight) {
37 std::string s=pythia.info.weightLabel(iWeight);
38 if (!s.length()) s=std::to_string((long long int)iWeight);
39 names.push_back(s);
40 }
41 if (!names.size()) names.push_back("default");
42 run->set_weight_names(names);
43 WriterAscii file(argv[2],run);
44
45 int nEvent = pythia.mode("Main:numberOfEvents");
46
47 for( int i = 0; i< nEvent; ++i ) {
48 if( !pythia.next() ) continue;
49
50 GenEvent hepmc( Units::GEV, Units::MM );
51
52 pythiaToHepMC.fill_next_event(pythia.event, &hepmc, -1, &pythia.info);
53
54 if( i==0 ) {
55 std::cout << "First event: " << std::endl;
56 Print::listing(hepmc);
57 }
58
59 file.write_event(hepmc);
60 }
61
62 file.close();
63 pythia.stat();
64}
Definition of class GenEvent.
Definition of static class Print.
Definition of class WriterAscii.
Stores event-related information.
Definition: GenEvent.h:41
static void listing(std::ostream &os, const GenEvent &event, unsigned short precision=2)
Print event in listing (HepMC2) format.
Definition: Print.cc:50
GenEvent I/O serialization for structured text files.
Definition: WriterAscii.h:25
HepMC3 main namespace.
Interrnal struct for keeping track of tools.
Definition: GenRunInfo.h:38