AliEMCalTriggerWeightHandler.cxx

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 * Author: The ALICE Off-line Project.                                    *
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 * documentation strictly for non-commercial purposes is hereby granted   *
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#include <TF1.h>

#include "AliEMCalTriggerWeightHandler.h"
#include "AliGenPythiaEventHeader.h"
#include "AliLog.h"
#include "AliMCEvent.h"

ClassImp(EMCalTriggerPtAnalysis::AliEMCalTriggerWeightHandler)

namespace EMCalTriggerPtAnalysis {

AliEMCalTriggerWeightHandler::AliEMCalTriggerWeightHandler() :
  fWeightModel(NULL),
  fUsePtHard(kTRUE)
{

}

double AliEMCalTriggerWeightHandler::GetEventWeight(const AliMCEvent* const event) const {
  if(!fWeightModel) {
    AliError("Weight model not set - returning 1");
    return 1.;
  }
  double weight = 1.;
  if(fUsePtHard){
    const AliGenPythiaEventHeader *header = dynamic_cast<const AliGenPythiaEventHeader *>(event->GenEventHeader());
    if(header)
      weight = fWeightModel->Eval(header->GetPtHard());
    else
      AliError("Event not a pythia event - returning 1");
  } else {
    // Using cross section
    const AliGenPythiaEventHeader *header = dynamic_cast<const AliGenPythiaEventHeader *>(event->GenEventHeader());
    if(header)
      weight = header->GetXsection()/static_cast<double>(header->Trials());
    else
      AliError("Event not a pythia event - returning 1");
  }
  return weight;
}

} /* namespace EMCalTriggerPtAnalysis */