BootstrapGeneratorAlg.h

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/*
  Copyright (C) 2002-2023 CERN for the benefit of the ATLAS collaboration
*/

 
#ifndef ASG_ANALYSIS_ALGORITHMS__BOOTSTRAP_GENERATOR_ALG_H
#define ASG_ANALYSIS_ALGORITHMS__BOOTSTRAP_GENERATOR_ALG_H
 
#include <AnaAlgorithm/AnaReentrantAlgorithm.h>
#include <AsgDataHandles/ReadHandleKey.h>
#include <AsgDataHandles/WriteDecorHandleKey.h>
#include <xAODEventInfo/EventInfo.h>
#include <AsgTools/PropertyWrapper.h>
#include <TRandomGen.h>
#include <vector>
 
namespace CP
{
  class BootstrapGenerator
  {
  public:
    BootstrapGenerator() {};

  public:
    std::uint64_t fnv1a_64(const void *buffer, size_t size, std::uint64_t offset_basis);

  public:
    void setSeed(std::uint64_t eventNumber, std::uint32_t runNumber, std::uint32_t mcChannelNumber);

  public:
    std::uint64_t generateSeed(std::uint64_t eventNumber, std::uint32_t runNumber, std::uint32_t mcChannelNumber);

  public:
    std::uint8_t getBootstrap() { return m_rng.Poisson(1); };

  private:
    static constexpr std::uint64_t m_offset = 14695981039346656037u;
    static constexpr std::uint64_t m_prime = 1099511628211u;

  private:
    TRandomRanluxpp m_rng;
  };
 

  class BootstrapGeneratorAlg final : public EL::AnaReentrantAlgorithm
  {
  public:
    using EL::AnaReentrantAlgorithm::AnaReentrantAlgorithm;
 
  public:
    StatusCode initialize() override;
 
  public:
    StatusCode execute(const EventContext& ctx) const override;

  private:
    SG::ReadHandleKey<xAOD::EventInfo> m_eventInfoKey{
      this, "eventInfo", "EventInfo", "the EventInfo container"};

  private:
    Gaudi::Property<int> m_nReplicas {this, "nReplicas", 1000, "number of bootstrapped weights (toys) to generate"};

  private:
    Gaudi::Property<bool> m_data {this, "isData", false, "whether we are running on data"};

  private:
    SG::WriteDecorHandleKey<xAOD::EventInfo> m_decorationKey{
      this, "decorationName", m_eventInfoKey, "bootstrapWeights", "decoration name for the vector of bootstrapped weights"};
  };
} // namespace CP
 
#endif