ParticleInventory.h

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////////////////////////////////////////////////////////////////////////
// ParticleInventory.h
// Provide a single interface for building and accessing truth information from events for backtracking services.
//
// author jason.stock@mines.sdsmt.edu
// Based on the original BackTracker by Brian Rebel (brebel@fnal.gov)
//
// This module may look strange at first glance beacause of the mutable
// object in const functions whose sole purpose is to change the mutable
// objects.
// This is done because the returns from the ParticleInventory really
// should be const, and anything called from them must then also be const,
// and finally we get to the mutables. These are cached objects to prevent
// repeated and costly access to objects in the event.
//
////////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////////
//DOXYGEN DOCUMENTATION
////////////////////////////////////////////////////////////////////////
/**
 * \file ParticleInventory.h
 * \author jason.stock@mines.sdsmt.edu
 * \brief Header for the ParticleInvenotry Service Provider.
 *
 * The ParticleInventory is an art independent service provider
 * for retreiving truth information about tracks and particles.
 * The ParticleInventory, BackTracker, and PhotonBackTracker make
 * a complete toolset for retreiving truth information from an event.
 */

/** \struct cheat::ParticleInventory::ParticleInventoryConfig
 *  \brief FHICL Validation Object
 *  This struct is used for loading the fhicl configuration.
 */
/** \var cheat::ParticleInventory::ParticleInventoryConfig::G4ModuleLabel
 *  \brief An atom.
 *  FHICL Atom for retreiving the module label to be used in retreiving
 *  information from the art event.
 *  */
/** \struct cheat::ParticleInventory::MCTObjects
 *  \brief  A simple struct to contain the MC Truth information.
 *  \var cheat::ParticleInventory::MCTObjects::fMCTruthList;
 *  \brief A vector containing the MCTruth objects
 *  \var cheat::ParticleInventory::MCTobjects::fTrackIdToMCTruthIndex
 *  \brief a map linking trackIds to the location of MCTruth for fast lookup.
 *  */

/** \fn void cheat::ParticleInventory::PrepEvent        ( const Evt& evt )
 *  \brief Function to set up the ParticleInventory state for an event.
 *  This is a function to tell the ParticleInventory to prepare itself to work with a particular event.
 *  @param evt
 *  \brief The event the ParticleInventory should work with. *Note. This use breaks the multithreading model because the service has a "state".
 *  */

/** \fn bool cheat::ParticleInventory::ParticleListReady()     const
 *  \brief A simple check to determine if the ParticleList has already been prepared for this event or not.
 *  */
/** \fn bool cheat::ParticleInventory::MCTruthListReady()      const
 *  \brief A simple check to determine if the MCTruthList has already been prepared and cached or not.
 *  */
/** \fn bool cheat::ParticleInventory::TrackIdToMCTruthReady() const
 *  \brief A simple check to determine if the TrackIdToMCTruth map has been prepared or not.
 *  */
/** \fn void cheat::ParticleInventory::PrepParticleList         (const Evt& evt ) const
 *  \brief A function to load the ParticleList and cache it
 *  This function will find the particle list and load it for later use.
 *  Ideally this would would be used for a "lazy" loading of the backtracker,
 *  but this does not work in the current setup of art.
 *  */
/** \fn void cheat::ParticleInventory::PrepTrackIdToMCTruthIndex(const Evt& evt ) const
 *  \brief A function to prepare and cache a map of TrackIds and MCTruth object indicies from fMCTruthList.
 *  */
/** \fn void cheat::ParticleInventory::PrepMCTruthList          (const Evt& evt ) const
 *  \brief A function to load and cache the MCTruthList of the event.
 *  */
/** \fn void cheat::ParticleInventory::PrepMCTruthListAndTrackIdToMCTruthIndex(const Evt& evt ) const
 *  \brief A function to make both PrepTrackIdToMCTruthIndex and PrepMCTruthList run when both are needed.
 *  */
/** \fn bool cheat::ParticleInventory::CanRun(const Evt& evt) const
 *  \brief A short function to check if use of the backtracker is appropriate or not based on the type of input file.
 *  This function simply checks to see if the file loaded is real data, or MC Simulation, as backtracking on real data makes no sense.
 *  If one does try to backtrack real data, this will throw and exception.
 *  */
/** \fn const sim::ParticleList& ParticleList() const
 *  \brief Get the ParticleList from an event.
 *  */
/** \fn  void SetEveIdCalculator(sim::EveIdCalculator *ec)
 *  \brief Set the EveIdCalculator to use for this ParticleList.
 *  Set the EveIdCalculator to use for this ParticleList. If you are
 *  going to over-ride the default EveIdCalculator, you must do it for
 *  EVERY event (as a new particle list is adopted for each event.
 */
/** \fn const std::vector< art::Ptr<simb::MCTruth> >& MCTruthList() const
 *  \brief Return a const reference to the list of MCTruth information from the event.
 *  This function provides a safe way for the user to access the complete MCTruth list
 *  as retrieved from the event.
 */
/** \fn const std::map<unsigned short, unsigned short >& TrackIdToMCTruthIndex() const
 *  \brief A map of TrackIds to Their coresponding MCTruth information.
 *  This returns the ParticleInventories internally maintained map of TrackID information to the index of the stored MCTruth information. While I toyed with using pointers or other similarly explicit references to the MCTruth information, this method won out for ease of use and low memory requirement.
 */
/** \fn void ClearEvent()
 *  \brief This function clears previosly cached information from the previous event. *Note, manually calling this function can cause the ParticleInventory and services depending on the ParticleInventory to behave incorrectly.
 */
/** \fn const simb::MCParticle* TrackIdToParticle_P(int const& id) const
 *  \brief Return a pointer to an MCParticle in the event that produced a given track.
 *  Returns a pointer (not an art::Ptr) to a particle in the event.
 */
/** \fn simb::MCParticle        TrackIdToParticle(int const& id) const
 * \brief Return a copy of the MCParticle that produced a given track.
 * Return a copy of the MCParticle that produced a given track. To conserve memory
 * users are encouraged to use TrackIdToParticle_P
 */
/** \fn const simb::MCParticle* TrackIdToMotherParticle_P(int const& id) const
 *  \brief Return a pointer to the MCParticle that is mother to the particle which created a given track.
 */
/** \fn simb::MCParticle        TrackIdToMotherParticle(int const& id) const
 *  \brief Returns a copy of the MCParticle that is mother to the particle which created a given track.
 *  Returns a copy of the MCParticle that is mother to the particle which created a given track. Due to
 *  memory conservation, users are encouraged to use TrackIdToMotherParticle_P
 */
/** \fn const art::Ptr<simb::MCTruth>& TrackIdToMCTruth_P(int const& id) const
 *  \brief Return an art::Ptr to an MCTruth object in the event that caused a given Track.
 *
 */
/** \fn simb::MCTruth                  TrackIdToMCTruth (int const& id) const
 *  \brief Return a copy of an MCTruth object in the event that caused a given Track.
 *  Return a copy of an MCTruth object in the event that caused a given Track. Users are encouraged
 *  to instead use TrackIdToMCTruth_P
 */
/** \fn int TrackIdToEveTrackId(const int& tid) const { return fParticleList.EveId(tid)
 *  \brief Return the TrackId of the primary that ultimately created the particle that made the given TrackId.
 */
/** \fn const art::Ptr<simb::MCTruth>& ParticleToMCTruth_P(const simb::MCParticle* p) const
 *  \brief Return an art::Ptr to the simb::MCTruth object that ultimately made the given particle
 */
/** \fn simb::MCTruth ParticleToMCTruth (const simb::MCParticle* p) const
 *  \brief Return a copy of the MCTruth object that ultimately resulted in the given particle
 */
/** \fn const std::vector< art::Ptr<simb::MCTruth> >& MCTruthVector_Ps() const
 *  \brief Get a list of pointers to the MCTruth objects in the event
 */
/** \fn const std::vector<const simb::MCParticle*> MCTruthToParticles_Ps(art::Ptr<simb::MCTruth> const& mct) const
 *  \brief Get pointers to all particles that resulted from the MCTruth object in the given art::Ptr
 */
/** \fn std::set<int> GetSetOfTrackIds() const
 *  \brief Get all TrackIds in the event
 */
/** \fn std::set<int> GetSetOfEveIds() const
 *  \brief Get all TrackIds of Primary particles in the event
 */

#ifndef CHEAT_PARTICLEINVENTORY_H
#define CHEAT_PARTICLEINVENTORY_H

#include <map>
#include <vector>

#include "canvas/Persistency/Common/Ptr.h"
#include "canvas/Utilities/InputTag.h"
#include "fhiclcpp/types/Atom.h"
namespace fhicl { class ParameterSet; }

namespace simb { class MCParticle; }
#include "nusimdata/SimulationBase/MCTruth.h"
#include "nug4/ParticleNavigation/ParticleList.h"

namespace cheat{
  class ParticleInventory
  {
    public:
      struct ParticleInventoryConfig{
        fhicl::Atom<art::InputTag> G4ModuleLabel{
          fhicl::Name("G4ModuleLabel"),
            fhicl::Comment("The label of the LArG4 module used to produce the art file we will be examining"),
            "largeant"};
        fhicl::Atom<std::string> EveIdCalculator{
          fhicl::Name("EveIdCalculator"),
            fhicl::Comment("For selecting which EveID caclulator to use at initialization."),
            "EmEveIdCalculator"};
        fhicl::Atom<bool> OverrideRealData{
          fhicl::Name("OverrideRealData"),
            fhicl::Comment("Option when overlaying simulation on real data, to tell the backtracker to continue even if event looks like data."),
            false};
      };

      //using provider_type = ParticleInventory;
      //cheat::ParticleInventory const* provider() const
      //{ return static_cast<cheat::ParticleInventory const*>(this); }

      ///////////Constructor///////////////
      ParticleInventory(const ParticleInventoryConfig& config );
      ParticleInventory(const fhicl::ParameterSet& pSet );
      ParticleInventory(ParticleInventory const&) = delete;

      template<typename Evt> //Template must be decalred and defined outside of the .cpp file.
        void PrepEvent        ( const Evt& evt );

      bool ParticleListReady()     const { return !( fParticleList.empty() ); }
      bool MCTruthListReady()      const { return !( (fMCTObj.fMCTruthList).empty()  ); }
      bool TrackIdToMCTruthReady() const { return !(fMCTObj.fTrackIdToMCTruthIndex.empty());}

      template<typename Evt>
        void PrepParticleList         (const Evt& evt ) const;
      template<typename Evt>
        void PrepTrackIdToMCTruthIndex(const Evt& evt ) const;
      template<typename Evt>
        void PrepMCTruthList          (const Evt& evt ) const;
      template<typename Evt>
        void PrepMCTruthListAndTrackIdToMCTruthIndex(const Evt& evt ) const ;
      template<typename Evt>
        bool CanRun(const Evt& evt) const;

      const sim::ParticleList& ParticleList() const { return fParticleList; }
      void SetEveIdCalculator(sim::EveIdCalculator *ec) { fParticleList.AdoptEveIdCalculator(ec); }

      const std::vector< art::Ptr<simb::MCTruth> >& MCTruthList() const { return fMCTObj.fMCTruthList;}

      const std::map< int,  int >& TrackIdToMCTruthIndex() const {return fMCTObj.fTrackIdToMCTruthIndex;}

      void ClearEvent();

      const simb::MCParticle* TrackIdToParticle_P(int const& id) const;
      simb::MCParticle        TrackIdToParticle(int const& id) const
      { return *(this->TrackIdToParticle_P(id)); }//Users are encouraged to use TrackIdToParticleP

      const simb::MCParticle* TrackIdToMotherParticle_P(int const& id) const;
      simb::MCParticle        TrackIdToMotherParticle(int const& id) const//Users are encouraged to use TrackIdToMotherParticleP
      { return *(this->TrackIdToMotherParticle_P(id)); }

      const art::Ptr<simb::MCTruth>& TrackIdToMCTruth_P(int const& id) const;
      simb::MCTruth                  TrackIdToMCTruth (int const& id) const//Users are encouraged to use TrackIdToMCTruthP
      { return *(this->TrackIdToMCTruth_P(id)); }

      //New Functions go here.
      //TrackIdToEveId.
      int TrackIdToEveTrackId(const int& tid) const { return fParticleList.EveId(tid);}

      const art::Ptr<simb::MCTruth>& ParticleToMCTruth_P(const simb::MCParticle* p) const; //Users are encouraged to use ParticleToMCTruthP
      simb::MCTruth                  ParticleToMCTruth (const simb::MCParticle* p) const
      { return *(this->ParticleToMCTruth_P(p)); }

      const std::vector< art::Ptr<simb::MCTruth> >& MCTruthVector_Ps() const; //I don't want this to be able to return a vector of copies. Too much chance of significant memory usage.

      std::vector<const simb::MCParticle*> MCTruthToParticles_Ps(art::Ptr<simb::MCTruth> const& mct) const; //I don't want this to be able to return a vector of copies. Too much chance of significant memory usage.

      std::set<int> GetSetOfTrackIds() const;
      std::set<int> GetSetOfEveIds() const;


    private:
      mutable sim::ParticleList                       fParticleList;
      struct MCTObjects{
        std::vector< art::Ptr<simb::MCTruth> >  fMCTruthList;   //there is some optimization that can be done here.
        std::map< int,  int > fTrackIdToMCTruthIndex;
      };
      mutable MCTObjects fMCTObj;
      //For fhicl validation, makea config struct
      art::InputTag fG4ModuleLabel;
      //std::string fEveIdCalculatorName;
      //enum EveIdCalculator
      //{
      //  EmEveIdCalculator,
      //  EveIdCalculator
      //}
      std::string fEveIdCalculator;
      bool fOverrideRealData;





  };//class ParticleInventory

}//namespace

#include "ParticleInventory.tcc"

#endif //CHEAT_PARTICLEINVENTORY_H