/data/refman/pasoursint/CMSSW_5_3_0/src/GeneratorInterface/RivetInterface/plugins/RivetAnalyzer.cc

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#include "GeneratorInterface/RivetInterface/interface/RivetAnalyzer.h"

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

#include "SimDataFormats/GeneratorProducts/interface/HepMCProduct.h"
#include "DataFormats/Common/interface/Handle.h"

#include "Rivet/AnalysisHandler.hh"
#include "Rivet/Analysis.hh"

#include <string>
#include <vector>
#include <iostream>
#include <cstdlib>
#include <cstring>

using namespace Rivet;
using namespace edm;

RivetAnalyzer::RivetAnalyzer(const edm::ParameterSet& pset) : 
_analysisHandler(),
_isFirstEvent(true),
_outFileName(pset.getParameter<std::string>("OutputFile"))
{
  //retrive the analysis name from paarmeter set
  std::vector<std::string> analysisNames = pset.getParameter<std::vector<std::string> >("AnalysisNames");
  
  _hepmcCollection = pset.getParameter<edm::InputTag>("HepMCCollection");

  //get the analyses
  _analysisHandler.addAnalyses(analysisNames);

  //go through the analyses and check those that need the cross section
  const std::set< AnaHandle, AnaHandleLess > & analyses = _analysisHandler.analyses();

  std::set< AnaHandle, AnaHandleLess >::const_iterator ibeg = analyses.begin();
  std::set< AnaHandle, AnaHandleLess >::const_iterator iend = analyses.end();
  std::set< AnaHandle, AnaHandleLess >::const_iterator iana; 
  double xsection = -1.;
  xsection = pset.getParameter<double>("CrossSection");
  for (iana = ibeg; iana != iend; ++iana){
    if ((*iana)->needsCrossSection())
      (*iana)->setCrossSection(xsection);
  }
}

RivetAnalyzer::~RivetAnalyzer(){
}

void RivetAnalyzer::beginJob(){
  //set the environment, very ugly but rivet is monolithic when it comes to paths
  char * cmsswbase    = getenv("CMSSW_BASE");
  char * cmsswrelease = getenv("CMSSW_RELEASE_BASE");
  std::string rivetref, rivetinfo;
  rivetref = "RIVET_REF_PATH=" + string(cmsswbase) + "/src/GeneratorInterface/RivetInterface/data:" + string(cmsswrelease) + "/src/GeneratorInterface/RivetInterface/data";
  rivetinfo = "RIVET_INFO_PATH=" + string(cmsswbase) + "/src/GeneratorInterface/RivetInterface/data:" + string(cmsswrelease) + "/src/GeneratorInterface/RivetInterface/data";
  putenv(strdup(rivetref.c_str()));
  putenv(strdup(rivetinfo.c_str()));
}

void RivetAnalyzer::beginRun(const edm::Run& iRun,const edm::EventSetup& iSetup){
  return;
}

void RivetAnalyzer::analyze(const edm::Event& iEvent,const edm::EventSetup& iSetup){
  
  //get the hepmc product from the event
  edm::Handle<HepMCProduct> evt;
  iEvent.getByLabel(_hepmcCollection, evt);

  // get HepMC GenEvent
  const HepMC::GenEvent *myGenEvent = evt->GetEvent();

  //aaply the beams initialization on the first event
  if (_isFirstEvent){
    _analysisHandler.init(*myGenEvent);
    _isFirstEvent = false;
  }

  //run the analysis
  _analysisHandler.analyze(*myGenEvent);
}


void RivetAnalyzer::endRun(const edm::Run& iRun,const edm::EventSetup& iSetup){
  return;
}

void RivetAnalyzer::endJob(){
  _analysisHandler.finalize();   
  _analysisHandler.writeData(_outFileName);
}

DEFINE_FWK_MODULE(RivetAnalyzer);