Pythia6Gun.cc

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/*
 *  \author Julia Yarba
 */
 
#include <iostream>
 
#include "Pythia6Gun.h"
 
//#include "SimGeneral/HepPDTRecord/interface/ParticleDataTable.h"
#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include "FWCore/Utilities/interface/Exception.h"
 
#include "FWCore/Framework/interface/EDProducer.h"
#include "FWCore/Framework/interface/Event.h"
#include "FWCore/Framework/interface/EventSetup.h"
#include "FWCore/Framework/interface/LuminosityBlock.h"
#include "FWCore/ServiceRegistry/interface/RandomEngineSentry.h"
 
#include "SimDataFormats/GeneratorProducts/interface/HepMCProduct.h"
 
using namespace edm;
using namespace gen;
 
Pythia6Gun::Pythia6Gun(const ParameterSet& pset)
    : fPy6Service(new Pythia6Service(pset)),
      fEvt(nullptr)
// fPDGTable( new DefaultConfig::ParticleDataTable("PDG Table") )
{
  ParameterSet pgun_params = pset.getParameter<ParameterSet>("PGunParameters");
 
  // although there's the method ParameterSet::empty(),
  // it looks like it's NOT even necessary to check if it is,
  // before trying to extract parameters - if it is empty,
  // the default values seem to be taken
  //
  fMinPhi = pgun_params.getParameter<double>("MinPhi");  // ,-3.14159265358979323846);
  fMaxPhi = pgun_params.getParameter<double>("MaxPhi");  // , 3.14159265358979323846);
 
  fHepMCVerbosity = pset.getUntrackedParameter<bool>("pythiaHepMCVerbosity", false);
  fPylistVerbosity = pset.getUntrackedParameter<int>("pythiaPylistVerbosity", 0);
  fMaxEventsToPrint = pset.getUntrackedParameter<int>("maxEventsToPrint", 0);
 
  // Turn off banner printout
  if (!call_pygive("MSTU(12)=12345")) {
    throw edm::Exception(edm::errors::Configuration, "PythiaError") << " pythia did not accept MSTU(12)=12345";
  }
 
  produces<HepMCProduct>("unsmeared");
}
 
Pythia6Gun::~Pythia6Gun() {
  if (fPy6Service)
    delete fPy6Service;
  //
  // note that GenEvent or any undelaying (GenVertex, GenParticle) do NOT
  // need to be cleaned, as it'll be done automatically by HepMCProduct
  //
}
 
void Pythia6Gun::beginJob() {
  // es.getData( fPDGTable ) ;
  return;
}
 
void Pythia6Gun::beginRun(Run const&, EventSetup const& es) {
  std::cout << " FYI: MSTU(10)=1 is ENFORCED in Py6-PGuns, for technical reasons" << std::endl;
  return;
}
 
void Pythia6Gun::beginLuminosityBlock(LuminosityBlock const& lumi, EventSetup const&) {
  assert(fPy6Service);
 
  RandomEngineSentry<Pythia6Service> sentry(fPy6Service, lumi.index());
 
  Pythia6Service::InstanceWrapper guard(fPy6Service);  // grab Py6 instance
 
  fPy6Service->setGeneralParams();
  fPy6Service->setCSAParams();
  fPy6Service->setSLHAParams();
 
  call_pygive("MSTU(10)=1");
 
  call_pyinit("NONE", "", "", 0.0);
}
 
void Pythia6Gun::endRun(Run const&, EventSetup const& es) {
  // here put in GenRunInfoProduct
 
  call_pystat(1);
 
  return;
}
 
void Pythia6Gun::attachPy6DecaysToGenEvent() {
  for (int iprt = fPartIDs.size(); iprt < pyjets.n; iprt++)  // the pointer is shifted by -1, c++ style
  {
    int parent = pyjets.k[2][iprt];
    if (parent != 0) {
      // pull up parent particle
      //
      HepMC::GenParticle* parentPart = fEvt->barcode_to_particle(parent);
      parentPart->set_status(2);  // reset status, to mark that it's decayed
 
      HepMC::GenVertex* DecVtx = new HepMC::GenVertex(
          HepMC::FourVector(pyjets.v[0][iprt], pyjets.v[1][iprt], pyjets.v[2][iprt], pyjets.v[3][iprt]));
      DecVtx->add_particle_in(parentPart);  // this will cleanup end_vertex if exists,
                                            // and replace with the new one
                                            // I presume barcode will be given automatically
 
      HepMC::FourVector pmom(pyjets.p[0][iprt], pyjets.p[1][iprt], pyjets.p[2][iprt], pyjets.p[3][iprt]);
 
      int dstatus = 0;
      if (pyjets.k[0][iprt] >= 1 && pyjets.k[0][iprt] <= 10) {
        dstatus = 1;
      } else if (pyjets.k[0][iprt] >= 11 && pyjets.k[0][iprt] <= 20) {
        dstatus = 2;
      } else if (pyjets.k[0][iprt] >= 21 && pyjets.k[0][iprt] <= 30) {
        dstatus = 3;
      } else if (pyjets.k[0][iprt] >= 31 && pyjets.k[0][iprt] <= 100) {
        dstatus = pyjets.k[0][iprt];
      }
      HepMC::GenParticle* daughter =
          new HepMC::GenParticle(pmom, HepPID::translatePythiatoPDT(pyjets.k[1][iprt]), dstatus);
      daughter->suggest_barcode(iprt + 1);
      DecVtx->add_particle_out(daughter);
      // give particle barcode as well !
 
      int iprt1;
      for (iprt1 = iprt + 1; iprt1 < pyjets.n; iprt1++)  // the pointer is shifted by -1, c++ style
      {
        if (pyjets.k[2][iprt1] != parent)
          break;  // another parent particle, break the loop
 
        HepMC::FourVector pmomN(pyjets.p[0][iprt1], pyjets.p[1][iprt1], pyjets.p[2][iprt1], pyjets.p[3][iprt1]);
 
        dstatus = 0;
        if (pyjets.k[0][iprt1] >= 1 && pyjets.k[0][iprt1] <= 10) {
          dstatus = 1;
        } else if (pyjets.k[0][iprt1] >= 11 && pyjets.k[0][iprt1] <= 20) {
          dstatus = 2;
        } else if (pyjets.k[0][iprt1] >= 21 && pyjets.k[0][iprt1] <= 30) {
          dstatus = 3;
        } else if (pyjets.k[0][iprt1] >= 31 && pyjets.k[0][iprt1] <= 100) {
          dstatus = pyjets.k[0][iprt1];
        }
        HepMC::GenParticle* daughterN =
            new HepMC::GenParticle(pmomN, HepPID::translatePythiatoPDT(pyjets.k[1][iprt1]), dstatus);
        daughterN->suggest_barcode(iprt1 + 1);
        DecVtx->add_particle_out(daughterN);
      }
 
      iprt = iprt1 - 1;  // reset counter such that it doesn't go over the same child more than once
                         // don't forget to offset back into c++ counting, as it's already +1 forward
 
      fEvt->add_vertex(DecVtx);
    }
  }
 
  return;
}
 
void Pythia6Gun::produce(edm::Event& evt, const edm::EventSetup&) {
  RandomEngineSentry<Pythia6Service> sentry(fPy6Service, evt.streamID());
 
  generateEvent(fPy6Service->randomEngine());
 
  fEvt->set_beam_particles(nullptr, nullptr);
  fEvt->set_event_number(evt.id().event());
  fEvt->set_signal_process_id(pypars.msti[0]);
 
  attachPy6DecaysToGenEvent();
 
  int evtN = evt.id().event();
  if (evtN <= fMaxEventsToPrint) {
    if (fPylistVerbosity) {
      call_pylist(fPylistVerbosity);
    }
    if (fHepMCVerbosity) {
      if (fEvt)
        fEvt->print();
    }
  }
 
  loadEvent(evt);
}
 
void Pythia6Gun::loadEvent(edm::Event& evt) {
  std::unique_ptr<HepMCProduct> bare_product(new HepMCProduct());
 
  if (fEvt)
    bare_product->addHepMCData(fEvt);
 
  evt.put(std::move(bare_product), "unsmeared");
 
  return;
}
 
HepMC::GenParticle* Pythia6Gun::addAntiParticle(int& ip, int& particleID, double& ee, double& eta, double& phi) {
  if (ip < 2)
    return nullptr;
 
  // translate PDG to Py6
  int py6PID = HepPID::translatePDTtoPythia(particleID);
  // Check if particle is its own anti-particle.
  int pythiaCode = pycomp_(py6PID);  // this is py6 internal validity check, it takes Pythia6 pid
                                     // so actually I'll need to convert
  int has_antipart = pydat2.kchg[3 - 1][pythiaCode - 1];
  int particleID2 = has_antipart ? -1 * particleID : particleID;  // this is PDG, for HepMC::GenEvent
  int py6PID2 = has_antipart ? -1 * py6PID : py6PID;              // this py6 id, for py1ent
  double the = 2. * atan(exp(eta));
  phi = phi + M_PI;
  if (phi > 2. * M_PI) {
    phi = phi - 2. * M_PI;
  }
 
  // copy over mass of the previous one, because then py6 will pick it up
  pyjets.p[4][ip - 1] = pyjets.p[4][ip - 2];
 
  py1ent_(ip, py6PID2, ee, the, phi);
 
  double px = pyjets.p[0][ip - 1];  // pt*cos(phi) ;
  double py = pyjets.p[1][ip - 1];  // pt*sin(phi) ;
  double pz = pyjets.p[2][ip - 1];  // mom*cos(the) ;
  HepMC::FourVector ap(px, py, pz, ee);
  HepMC::GenParticle* APart = new HepMC::GenParticle(ap, particleID2, 1);
  APart->suggest_barcode(ip);
 
  return APart;
}