/afs/cern.ch/work/a/aaltunda/public/www/CMSSW_6_2_5/src/GeneratorInterface/LHEInterface/plugins/LHE2HepMCConverter.cc

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// -*- C++ -*-
//
// Package:    LHE2HepMCConverter
// Class:      LHE2HepMCConverter
// 
//
// Original Author:  Piergiulio Lenzi,40 1-B01,+41227671638,
//         Created:  Wed Aug 31 19:02:24 CEST 2011
// $Id: LHE2HepMCConverter.cc,v 1.2 2013/03/01 21:45:29 wdd Exp $
//
//


// system include files
#include <memory>

#include <boost/shared_ptr.hpp>

// user include files
#include "FWCore/Framework/interface/Frameworkfwd.h"
#include "FWCore/Framework/interface/EDProducer.h"

#include "FWCore/Framework/interface/Event.h"
#include "FWCore/Framework/interface/Run.h"
#include "FWCore/Framework/interface/MakerMacros.h"

#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include "FWCore/Utilities/interface/InputTag.h"
#include "DataFormats/Common/interface/Handle.h"

#include "SimDataFormats/GeneratorProducts/interface/LHEEventProduct.h"
#include "SimDataFormats/GeneratorProducts/interface/LHERunInfoProduct.h"
#include "SimDataFormats/GeneratorProducts/interface/HepMCProduct.h"

//
// class declaration
//

class LHE2HepMCConverter : public edm::EDProducer {
   public:
      explicit LHE2HepMCConverter(const edm::ParameterSet&);
      ~LHE2HepMCConverter();

      static void fillDescriptions(edm::ConfigurationDescriptions& descriptions);

   protected:

  //      lhef::LHERunInfo *lheRunInfo() { return lheRunInfo_.get(); }

   private:

      virtual void produce(edm::Event&, const edm::EventSetup&) override;
      virtual void beginRun(edm::Run const&, edm::EventSetup const&) override;

      // ----------member data ---------------------------
      edm::InputTag _lheEventSrcTag;
      edm::InputTag _lheRunSrcTag;
      const LHERunInfoProduct* _lheRunSrc;

  //      boost::shared_ptr<lhef::LHERunInfo> lheRunInfo_;

};

//
// constants, enums and typedefs
//


//
// static data member definitions
//

//
// constructors and destructor
//
LHE2HepMCConverter::LHE2HepMCConverter(const edm::ParameterSet& iConfig):
_lheRunSrc(0)
{
   //register your products
   produces<edm::HepMCProduct>();

   _lheEventSrcTag = iConfig.getParameter<edm::InputTag>("LHEEventProduct");
   _lheRunSrcTag   = iConfig.getParameter<edm::InputTag>("LHERunInfoProduct");

}


LHE2HepMCConverter::~LHE2HepMCConverter()
{
 
   // do anything here that needs to be done at desctruction time
   // (e.g. close files, deallocate resources etc.)

}


//
// member functions
//

// ------------ method called to produce the data  ------------
void
LHE2HepMCConverter::produce(edm::Event& iEvent, const edm::EventSetup& iSetup)
{
   using namespace edm;
   Handle<LHEEventProduct> lheEventSrc;
   iEvent.getByLabel(_lheEventSrcTag, lheEventSrc);

   HepMC::GenEvent *evt = new HepMC::GenEvent();
   HepMC::GenVertex* v = new HepMC::GenVertex();
   evt->add_vertex(v);
   if (_lheRunSrc){
     HepMC::FourVector beam1(0, 0, _lheRunSrc->heprup().EBMUP.first, _lheRunSrc->heprup().EBMUP.first);
     HepMC::GenParticle* gp1 = new HepMC::GenParticle(beam1, _lheRunSrc->heprup().IDBMUP.first, 4);
     v->add_particle_in(gp1);
     HepMC::FourVector beam2(0, 0, _lheRunSrc->heprup().EBMUP.second, _lheRunSrc->heprup().EBMUP.second);
     HepMC::GenParticle* gp2 = new HepMC::GenParticle(beam2, _lheRunSrc->heprup().IDBMUP.second, 4);
     v->add_particle_in(gp2);
     evt->set_beam_particles(gp1, gp2);
   } else {
     LogWarning("LHE2HepMCConverter") << "Could not retrieve the LHERunInfoProduct for this event. You'll miss the beam particles in your HepMC product." ; 
   }


   for (int i = 0; i < lheEventSrc->hepeup().NUP; ++i) {
      if (lheEventSrc->hepeup().ISTUP[i] != 1) {
       //cout << reader->hepeup.ISTUP[i] << ", " << reader->hepeup.IDUP[i] << endl;
       continue;
      }
      HepMC::FourVector p(lheEventSrc->hepeup().PUP[i][0], lheEventSrc->hepeup().PUP[i][1],
                          lheEventSrc->hepeup().PUP[i][2], lheEventSrc->hepeup().PUP[i][3]);
      HepMC::GenParticle* gp = new HepMC::GenParticle(p, lheEventSrc->hepeup().IDUP[i], 1);
      gp->set_generated_mass(lheEventSrc->hepeup().PUP[i][4]);
      v->add_particle_out(gp);
   } 

   std::auto_ptr<HepMCProduct> pOut(new HepMCProduct(evt));
   iEvent.put(pOut);

}

// ------------ method called when starting to processes a run  ------------
void
LHE2HepMCConverter::beginRun(edm::Run const& iRun, edm::EventSetup const&)
{
  
  edm::Handle<LHERunInfoProduct> lheRunSrcHandle;
  iRun.getByLabel(_lheRunSrcTag, lheRunSrcHandle);
  if (lheRunSrcHandle.isValid()) {
    _lheRunSrc = lheRunSrcHandle.product();
  }
  else {
    if (_lheRunSrcTag.label() != "source" ) {
      iRun.getByLabel("source", lheRunSrcHandle);
      if (lheRunSrcHandle.isValid()) {
        _lheRunSrc = lheRunSrcHandle.product();
        edm::LogInfo("LHE2HepMCConverter") << "Taking LHERunInfoproduct from source";
      }
      else
        edm::LogWarning("LHE2HepMCConverter") << "No LHERunInfoProduct from source"; 
    }

  }

}

// ------------ method fills 'descriptions' with the allowed parameters for the module  ------------
void
LHE2HepMCConverter::fillDescriptions(edm::ConfigurationDescriptions& descriptions) {
  //The following says we do not know what parameters are allowed so do no validation
  // Please change this to state exactly what you do use, even if it is no parameters
  edm::ParameterSetDescription desc;
  desc.setUnknown();
  descriptions.addDefault(desc);
}

//define this as a plug-in
DEFINE_FWK_MODULE(LHE2HepMCConverter);