LightSource_module.cc

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#ifndef EVGEN_LIGHTSOURCE_H
#define EVGEN_LIGHTSOURCE_H

// C++ includes.
#include <iostream>
#include <string>
#include <cmath>
#include <memory>
#include <fstream>

// ART includes
#include "art/Framework/Core/EDProducer.h"
#include "art/Framework/Principal/Event.h"
#include "fhiclcpp/ParameterSet.h"
#include "art/Framework/Principal/Handle.h"
#include "art/Framework/Services/Registry/ServiceHandle.h"
#include "art/Framework/Services/Optional/TFileService.h"
#include "art/Framework/Services/Optional/TFileDirectory.h"
#include "messagefacility/MessageLogger/MessageLogger.h"
#include "art/Framework/Core/ModuleMacros.h"
#include "canvas/Utilities/Exception.h"
#include "cetlib_except/exception.h"

// art extensions
#include "nutools/RandomUtils/NuRandomService.h"

// nutools includes
#include "nusimdata/SimulationBase/MCTruth.h"
#include "nusimdata/SimulationBase/MCParticle.h"
#include "nutools/EventGeneratorBase/evgenbase.h"

// lar includes
#include "larcore/Geometry/Geometry.h"
#include "larsim/Simulation/PhotonVoxels.h"
#include "larsim/PhotonPropagation/PhotonVisibilityService.h"
#include "larcoreobj/SummaryData/RunData.h"
#include "larsim/Simulation/PhotonVoxels.h"

#include "TVector3.h"
#include "TLorentzVector.h"
#include "TTree.h"

#include "CLHEP/Random/RandFlat.h"
#include "CLHEP/Random/RandGaussQ.h"

namespace evgen {

  class LightSource : public art::EDProducer {
  public:
    explicit LightSource(fhicl::ParameterSet const& pset);
    
    void produce(art::Event & evt);
    void beginRun(art::Run& run);

  private:

    void Sample(simb::MCTruth &truth);
         
    // for c2: fSeed is unused
    //int               fSeed;              //random number seed
    std::string       fVersion;           //version of the configuration

    // Flags to mark module modes 
    static const int  kUNIF = 0;
    static const int  kGAUS = 1;
    static const int  kFILE = 0;
    static const int  kSCAN = 1;

    // File stream, filename and empty string for file processing
    std::ifstream      fInputFile;
    std::string        fFileName;      
    char               fDummyString[256];

    // A ttree to keep track of where particles have been shot - ends up in histos.root
    TTree *            fPhotonsGenerated;
    TLorentzVector     fShotPos;
    TLorentzVector     fShotMom;
    Int_t              fEvID;

    // Parameters loaded from config - both modes
    int                fSourceMode;     // Mode to run in - scan or file
    bool               fFillTree;       // Do we want to create a TTree of shot particles?
    int                fPosDist;        //
    int                fTDist;          // Random distributions to use : 1= gauss, 0= uniform
    int                fPDist;          //  

    //Scan mode specific parameters
    int fXSteps;                        //
    int fYSteps;                        //  Number of steps to take in each dimension
    int fZSteps;                        // 

    sim::PhotonVoxelDef fThePhotonVoxelDef;  // The photon voxel definition object for scan mode

    int fVoxelCount;                    // Total number of voxels
    int fCurrentVoxel;                  // Counter to keep track of vox ID


    //  TPC Measurements
    TVector3 fTPCCenter;    
    TVector3 fTPCDimensions;           
    std::vector<double> fRegionMin;
    std::vector<double> fRegionMax;
    bool fUseCustomRegion;
    

    // Parameters used to shoot in distributions
    double              fX;              // central x position of source
    double              fY;              // central y position of source
    double              fZ;              // central z position of source
    bool                fPointSource;    // Point-like light source in fX, fY, fZ
    double              fT;              // central t position of source
    double              fSigmaX;         // x width
    double              fSigmaY;         // y width
    double              fSigmaZ;         // z width
    double              fSigmaT;         // t width
    double              fP;              // central momentm of photon 
    double              fSigmaP;         // mom width;

    // Number of photons per event
    int                fN;              // number of photons per event
    
    int                fFirstVoxel;
    int                fLastVoxel;
  };
}

namespace evgen{
  
  //----------------------------------------------------------------
  LightSource::LightSource(fhicl::ParameterSet const& pset) 
  {

    // get the random number seed, use a random default if not specified    
    // in the configuration file.  
 
    fSourceMode   =     (pset.get<int >("SourceMode")  );
    fFillTree     =     (pset.get<bool>("FillTree")    );
    fPosDist      =     (pset.get<int >("PosDist")     );
    fPDist        =     (pset.get<int >("PDist")       );
    fTDist        =     (pset.get<int >("TDist")       );
    
    // create a default random engine; obtain the random seed from NuRandomService,
    // unless overridden in configuration with key "Seed"
    art::ServiceHandle<rndm::NuRandomService>()
      ->createEngine(*this, pset, "Seed");

    // load optional parameters in function
    produces< sumdata::RunData, art::InRun >();
    produces< std::vector<simb::MCTruth> >();
 
    if(fSourceMode==kFILE)
      {
        fFileName  = pset.get<std::string>("SteeringFile");
        fInputFile.open(fFileName.c_str());
        fInputFile.getline(fDummyString,256);

      }
    else if (fSourceMode==kSCAN)
      {
        fT      = pset.get<double>("T0");
        fSigmaT = pset.get<double>("SigmaT");
        fN      = pset.get<int   >("N");

        fFirstVoxel     = pset.get<int   >("FirstVoxel");
        fLastVoxel      = pset.get<int   >("LastVoxel");
        
        fP      = pset.get<double>("P");
        fSigmaP = pset.get<double>("SigmaP");

        fUseCustomRegion = pset.get<bool>("UseCustomRegion");
        fPointSource = pset.get<bool>("PointSource",false);

        if(fUseCustomRegion)
          {     
            fRegionMin = pset.get< std::vector<double> >("RegionMin");
            fRegionMax = pset.get< std::vector<double> >("RegionMax");
            fXSteps = pset.get<int >("XSteps");
            fYSteps = pset.get<int >("YSteps");
            fZSteps = pset.get<int >("ZSteps");
          }

        art::ServiceHandle<geo::Geometry> geo;
        // get TPC dimensions removed. -TA


        fCurrentVoxel=0;

        // define voxelization based on parameters read from config.
        // There are two modes - either read the dimensions of the TPC from
        // the geometry, or use values specified by the user.
        if(!fUseCustomRegion)
          {
            art::ServiceHandle<phot::PhotonVisibilityService> vis;   
            fThePhotonVoxelDef = vis->GetVoxelDef();
          }
        else
          {
            fThePhotonVoxelDef = sim::PhotonVoxelDef(fRegionMin[0], 
                                                     fRegionMax[0],
                                                     fXSteps,
                                                     fRegionMin[1],
                                                     fRegionMax[1],
                                                     fYSteps,
                                                     fRegionMin[2],
                                                     fRegionMax[2],
                                                     fZSteps);   
          }
        

        // Set distribution widths to voxel size

        fSigmaX = fThePhotonVoxelDef.GetVoxelSize().X()/2.0;
        fSigmaY = fThePhotonVoxelDef.GetVoxelSize().Y()/2.0;
        fSigmaZ = fThePhotonVoxelDef.GetVoxelSize().Z()/2.0;

        // Get number of voxels we will step through
        
        fVoxelCount = fThePhotonVoxelDef.GetNVoxels();
        
        if(fLastVoxel<0) fLastVoxel = fVoxelCount;
        
        mf::LogVerbatim("LightSource") << "Light Source : Determining voxel params : " 
                                       << fVoxelCount << " " 
                                       << fSigmaX     << " "
                                       << fSigmaY     << " " 
                                       <<fSigmaZ;

      }
    else{
      throw cet::exception("LightSource") << "EVGEN Light Source : Unrecognised light source mode\n";
    }
    



    if(fFillTree)
      {
        art::ServiceHandle<art::TFileService> tfs;
        fPhotonsGenerated = tfs->make<TTree>("PhotonsGenerated","PhotonsGenerated");
        fPhotonsGenerated->Branch("X",&(fShotPos[0]),"X/D");
        fPhotonsGenerated->Branch("Y",&(fShotPos[1]),"Y/D");
        fPhotonsGenerated->Branch("Z",&(fShotPos[2]),"Z/D");
        fPhotonsGenerated->Branch("T",&(fShotPos[3]),"T/D");
        fPhotonsGenerated->Branch("PX",&(fShotMom[0]),"PX/D");
        fPhotonsGenerated->Branch("PY",&(fShotMom[1]),"PY/D");
        fPhotonsGenerated->Branch("PZ",&(fShotMom[2]),"PZ/D");
        fPhotonsGenerated->Branch("PT",&(fShotMom[3]),"PT/D");
        fPhotonsGenerated->Branch("EventID",&fEvID,"EventID/I");
      }
  }


  //____________________________________________________________________________
  void LightSource::beginRun(art::Run& run)
  {

    // grab the geometry object to see what geometry we are using
    art::ServiceHandle<geo::Geometry> geo;
    std::unique_ptr<sumdata::RunData> runcol(new sumdata::RunData(geo->DetectorName()));

    run.put(std::move(runcol));
    
    fCurrentVoxel=fFirstVoxel;

    return;
  }

  //----------------------------------------------------------------
  void LightSource::produce(art::Event& evt)
  {
    
    // FILE MODE -
    //  Each event, read coordinates of gun and number of photons to shoot from file
    
    if(fSourceMode==kFILE)
      {
        // Loop file if required
        if(fInputFile.eof()){
          mf::LogWarning("LightSource") << "EVGEN Light Source : Warning, reached end of file,"
                                        << " looping back to beginning";
          fInputFile.seekg(0,std::ios::beg);
          fInputFile.clear();
        }
        
        if(!fInputFile.is_open() || fInputFile.fail() ){
          throw cet::exception("LightSource") << "EVGEN Light Source : File error in " 
                                              << fFileName << "\n";
        }
        else{ 
          // read in one line
          fInputFile >> fX >> fY >> fZ >> fT 
                     >> fSigmaX >> fSigmaY >> fSigmaZ >> fSigmaT 
                     >> fP >> fSigmaP >> fN;
          fInputFile.getline(fDummyString,256);
          fThePhotonVoxelDef = sim::PhotonVoxelDef(fX - fSigmaX, 
                                                   fX + fSigmaX,
                                                   1,
                                                   fY - fSigmaY,
                                                   fY + fSigmaY,
                                                   1,
                                                   fZ - fSigmaZ,
                                                   fZ + fSigmaZ,
                                                   1);   
            
          fCurrentVoxel=0;
        }
      }


    // SCAN MODE -
    //  Step through detector using a number of steps provided in the config file
    //  firing a constant number of photons from each point
    else if(fSourceMode==kSCAN)
      {


        TVector3 VoxelCenter = fThePhotonVoxelDef.GetPhotonVoxel(fCurrentVoxel).GetCenter();
        
        fX = VoxelCenter.X();
        fY = VoxelCenter.Y();
        fZ = VoxelCenter.Z();
        
      }
        
    
    // UNRECOGNISED MODE 
    //  - neither file or scan mode, probably a config file error

    else{
      throw cet::exception("LightSource") <<"EVGEN : Light Source, unrecognised source mode\n";
    }
    


    //    std::cout<<"EVGEN Light source to be placed at  (x, y, z, t, dx, dy, dz, dt, n) " <<
    //      fX << " " << fY << " " <<fZ << " " << fT << " " << 
    //      fSigmaX << " " << fSigmaY << " " << fSigmaZ << " " << fSigmaT << " " <<
    //      fN << std::endl<<std::endl;
    
      
    std::unique_ptr< std::vector<simb::MCTruth> > truthcol(new std::vector<simb::MCTruth>);

    simb::MCTruth truth;
    truth.SetOrigin(simb::kSingleParticle);
    Sample(truth);
    
    //     std::cout << "put mctruth into the vector" << std::endl;
    truthcol->push_back(truth);

    //     std::cout << "add vector to the event " << truthcol->size() << std::endl;
    evt.put(std::move(truthcol));
    
    phot::PhotonVisibilityService* vis = nullptr;
    try {
      vis = art::ServiceHandle<phot::PhotonVisibilityService>().get();
    }
    catch (art::Exception const& e) {
      // if the service is not configured, then this is not a build job
      // (it is a simple generation job instead)
      if (e.categoryCode() != art::errors::ServiceNotFound) throw;
    }

    if(vis && vis->IsBuildJob())
      {
        mf::LogVerbatim("LightSource") << "Light source : Stowing voxel params ";
        vis->StoreLightProd(fCurrentVoxel,fN);
      }

    if(fCurrentVoxel!=fLastVoxel) 
      {
        ++fCurrentVoxel;
      }
    else
      {
        mf::LogVerbatim("LightSource") << "EVGEN Light Source fully scanned detector.  Starting over.";
        fCurrentVoxel=fFirstVoxel;
      }
    
    return;


  }


  void LightSource::Sample(simb::MCTruth& mct) 
  {
    mf::LogVerbatim("LightSource") <<"Light source debug : Shooting at " << fX <<" " << fY<<" "<< fZ;
    
    // get the random number generator service and make some CLHEP generators
    art::ServiceHandle<art::RandomNumberGenerator> rng;
    CLHEP::HepRandomEngine &engine = rng->getEngine();
    CLHEP::RandFlat   flat(engine);
    CLHEP::RandGaussQ gauss(engine);

    for(int j=0; j!=fN; ++j){
      // Choose momentum (supplied in eV, convert to GeV)
      double p = fP;
      if (fPDist == kGAUS) {
        p = gauss.fire(fP, fSigmaP);
      }
      else {
        p = fP + fSigmaP*(2.0*flat.fire()-1.0);
      }
      p /= 1000000000.;
      
      // Choose position
      TVector3 x;
      if(fPointSource) {
        x[0] = fX;
        x[1] = fY;
        x[2] = fZ;
      }
      else {
        if (fPosDist == kGAUS) {
          x[0] = gauss.fire(fX, fSigmaX);
          x[1] = gauss.fire(fY, fSigmaY);
          x[2] = gauss.fire(fZ, fSigmaZ);
        }
        else {
          x[0] = fX + fSigmaX*(2.0*flat.fire()-1.0);
          x[1] = fY + fSigmaY*(2.0*flat.fire()-1.0);
          x[2] = fZ + fSigmaZ*(2.0*flat.fire()-1.0);
        }

      }
      
      // Choose time
      double t;
      if (fTDist == kGAUS) {
        t = gauss.fire(fT, fSigmaT);
      }
      else {
        t = fT + fSigmaT * (2.0 * flat.fire()-1.0);
      }
        
        
      //assume the position is relative to the center of the TPC
      //x += fTPCCenter;
        
      fShotPos = TLorentzVector(x[0], x[1], x[2], t);
        

      // Choose angles
      double costh = 2 * flat.fire() - 1;
      double sinth = pow(1-pow(costh,2),0.5);
      double phi   = 2 * M_PI * flat.fire();
      
      // Generate momentum 4-vector
      
      fShotMom = TLorentzVector( p*sinth*cos(phi), 
                                 p*sinth*sin(phi), 
                                 p*costh, 
                                 p                  );
        
      int trackid = -1*(j+1); // set track id to -i as these are all primary particles and have id <= 0
      std::string primary("primary");
      int PDG=0; //optical photons have PDG 0

      simb::MCParticle part(trackid, PDG, primary);
      part.AddTrajectoryPoint(fShotPos, fShotMom);

      if(fFillTree)
        fPhotonsGenerated->Fill();
        
      mct.Add(part);
    }

  }


}


namespace evgen{

  DEFINE_ART_MODULE(LightSource)

}//end namespace evgen


#endif // EVGEN_LIGHTSOURCE_H