/afs/cern.ch/work/a/aaltunda/public/www/CMSSW_6_2_7/src/SimTracker/SiPixelDigitizer/plugins/SiPixelDigitizerAlgorithm.h

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#ifndef SiPixelDigitizerAlgorithm_h
#define SiPixelDigitizerAlgorithm_h

#include <map>
#include <memory>
#include <vector>
#include <iostream>
#include "DataFormats/GeometrySurface/interface/GloballyPositioned.h"
#include "DataFormats/GeometryVector/interface/LocalPoint.h"
#include "FWCore/Framework/interface/ESHandle.h"
#include "SimDataFormats/EncodedEventId/interface/EncodedEventId.h"
#include "SimDataFormats/TrackingHit/interface/PSimHit.h"
#include "SimTracker/Common/interface/SimHitInfoForLinks.h"
#include "DataFormats/Math/interface/approx_exp.h"

// forward declarations


// For the random numbers
namespace CLHEP {
  class HepRandomEngine;
  class RandGaussQ;
  class RandFlat;
}

namespace edm {
  class EventSetup;
  class ParameterSet;
}

class DetId;
class GaussianTailNoiseGenerator;
class PixelDigi;
class PixelDigiSimLink;
class PixelGeomDetUnit;
class SiG4UniversalFluctuation;
class SiPixelFedCablingMap;
class SiPixelGainCalibrationOfflineSimService;
class SiPixelLorentzAngle;
class SiPixelQuality;
class TrackerGeometry;
class TrackerTopology;

class SiPixelDigitizerAlgorithm  {
 public:
  SiPixelDigitizerAlgorithm(const edm::ParameterSet& conf, CLHEP::HepRandomEngine&);
  ~SiPixelDigitizerAlgorithm();

  // initialization that cannot be done in the constructor
  void init(const edm::EventSetup& es);
  
  void initializeEvent() {
    _signal.clear();
  }

  //run the algorithm to digitize a single det
  void accumulateSimHits(const std::vector<PSimHit>::const_iterator inputBegin,
                         const std::vector<PSimHit>::const_iterator inputEnd,
                         const PixelGeomDetUnit *pixdet,
                         const GlobalVector& bfield);
  void digitize(const PixelGeomDetUnit *pixdet,
                std::vector<PixelDigi>& digis,
                std::vector<PixelDigiSimLink>& simlinks,
                const TrackerTopology *tTopo);

 private:
  
  //Accessing Lorentz angle from DB:
  edm::ESHandle<SiPixelLorentzAngle> SiPixelLorentzAngle_;

  //Accessing Dead pixel modules from DB:
  edm::ESHandle<SiPixelQuality> SiPixelBadModule_;

  //Accessing Map and Geom:
  edm::ESHandle<SiPixelFedCablingMap> map_;
  edm::ESHandle<TrackerGeometry> geom_;

  // Define internal classes

  // definition class
  //
  class Amplitude {
  public:
    Amplitude() : _amp(0.0) {}
    Amplitude( float amp, float frac) :
      _amp(amp), _frac(1, frac), _hitInfo() {
    //in case of digi from noisypixels
      //the MC information are removed 
      if (_frac[0]<-0.5) {
        _frac.pop_back();
      }
    }

    Amplitude( float amp, const PSimHit* hitp, float frac) :
      _amp(amp), _frac(1, frac), _hitInfo(new SimHitInfoForLinks(hitp)) {

    //in case of digi from noisypixels
      //the MC information are removed 
      if (_frac[0]<-0.5) {
        _frac.pop_back();
        _hitInfo->trackIds_.pop_back();
      }
    }

    // can be used as a float by convers.
    operator float() const { return _amp;}
    float ampl() const {return _amp;}
    std::vector<float> individualampl() const {return _frac;}
    const std::vector<unsigned int>& trackIds() const {
      return _hitInfo->trackIds_;
    }
    const std::shared_ptr<SimHitInfoForLinks>& hitInfo() const {return _hitInfo;}

    void operator+=( const Amplitude& other) {
      _amp += other._amp;
      //in case of contribution of noise to the digi
      //the MC information are removed 
      if (other._frac[0]>-0.5){
        if(other._hitInfo) {
          std::vector<unsigned int>& otherTrackIds = other._hitInfo->trackIds_;
          if(_hitInfo) {
            std::vector<unsigned int>& trackIds = _hitInfo->trackIds_;
            trackIds.insert(trackIds.end(), otherTrackIds.begin(), otherTrackIds.end());
          } else {
            _hitInfo.reset(new SimHitInfoForLinks(*other._hitInfo));
          }
        }
        _frac.insert(_frac.end(), other._frac.begin(), other._frac.end());
      }
   }
   const EncodedEventId& eventId() const {
     return _hitInfo->eventId_;
   }
    void operator+=( const float& amp) {
      _amp += amp;
    }
   
    void set (const float amplitude) {  // Used to reset the amplitude
      _amp = amplitude;
    }
/*     void setind (const float indamplitude) {  // Used to reset the amplitude */
/*       _frac = idamplitude; */
/*     } */
  private:
    float _amp;
    std::vector<float> _frac;
    std::shared_ptr<SimHitInfoForLinks> _hitInfo;
  };  // end class Amplitude

  // Define a class to hold the calibration parameters per pixel
  // Internal
  class CalParameters {
  public:
    float p0;
    float p1;
    float p2;
    float p3;
  };
  //
  // Define a class for 3D ionization points and energy
  //
  class EnergyDepositUnit{
  public:
    EnergyDepositUnit(): _energy(0),_position(0,0,0){}
    EnergyDepositUnit(float energy,float x, float y, float z):
    _energy(energy),_position(x,y,z){}
    EnergyDepositUnit(float energy, Local3DPoint position):
    _energy(energy),_position(position){}
    float x() const{return _position.x();}
    float y() const{return _position.y();}
    float z() const{return _position.z();}
    float energy() const { return _energy;}
  private:
    float _energy;
    Local3DPoint _position;
  };

  //
  // define class to store signals on the collection surface
  //
  class SignalPoint {
  public:
    SignalPoint() : _pos(0,0), _time(0), _amplitude(0), 
      _sigma_x(1.), _sigma_y(1.), _hitp(0) {}
    
    SignalPoint( float x, float y, float sigma_x, float sigma_y,
                 float t, float a=1.0) :
    _pos(x,y), _time(t), _amplitude(a), _sigma_x(sigma_x), 
      _sigma_y(sigma_y), _hitp(0) {}
    
    SignalPoint( float x, float y, float sigma_x, float sigma_y,
                 float t, const PSimHit& hit, float a=1.0) :
    _pos(x,y), _time(t), _amplitude(a), _sigma_x(sigma_x), 
      _sigma_y(sigma_y),_hitp(&hit) {}
    
    const LocalPoint& position() const { return _pos;}
    float x()         const { return _pos.x();}
    float y()         const { return _pos.y();}
    float sigma_x()   const { return _sigma_x;}
    float sigma_y()   const { return _sigma_y;}
    float time()      const { return _time;}
    float amplitude() const { return _amplitude;}
    const PSimHit& hit()           { return *_hitp;}
    SignalPoint& set_amplitude( float amp) { _amplitude = amp; return *this;}
    
  

  private:
    LocalPoint         _pos;
    float              _time;
    float              _amplitude;
    float              _sigma_x;   // gaussian sigma in the x direction (cm)
    float              _sigma_y;   //    "       "          y direction (cm) */
    const PSimHit*   _hitp;
  };
 
  //
  // PixelEfficiencies struct
  //
   struct PixelEfficiencies {
     PixelEfficiencies(const edm::ParameterSet& conf, bool AddPixelInefficiency, int NumberOfBarrelLayers, int NumberOfEndcapDisks);
     float thePixelEfficiency[20];     // Single pixel effciency
     float thePixelColEfficiency[20];  // Column effciency
     float thePixelChipEfficiency[20]; // ROC efficiency
     unsigned int FPixIndex;         // The Efficiency index for FPix Disks
   };

 private:

    // Internal typedefs
    typedef std::map<int, Amplitude, std::less<int> > signal_map_type;  // from Digi.Skel.
    typedef signal_map_type::iterator          signal_map_iterator; // from Digi.Skel.  
    typedef signal_map_type::const_iterator    signal_map_const_iterator; // from Digi.Skel.  
    typedef std::map<unsigned int, std::vector<float>,std::less<unsigned int> > simlink_map;
    typedef std::map<uint32_t, signal_map_type> signalMaps;
    typedef GloballyPositioned<double>      Frame;
    typedef std::vector<edm::ParameterSet> Parameters;

    // Contains the accumulated hit info.
    signalMaps _signal;

    const bool makeDigiSimLinks_;

    const bool use_ineff_from_db_;
    const bool use_module_killing_; // remove or not the dead pixel modules
    const bool use_deadmodule_DB_; // if we want to get dead pixel modules from the DataBase.
    const bool use_LorentzAngle_DB_; // if we want to get Lorentz angle from the DataBase.

    const Parameters DeadModules;

    // Variables 
    //external parameters 
    // go from Geant energy GeV to number of electrons
    const float GeVperElectron; // 3.7E-09 
    
    //-- drift
    const float Sigma0; //=0.0007  // Charge diffusion in microns for 300 micron Si
    const float Dist300;  //=0.0300  // Define 300microns for normalization 
    const bool alpha2Order;          // Switch on/off of E.B effect 


 
    //-- induce_signal
    const float ClusterWidth;       // Gaussian charge cutoff width in sigma units
    //-- Allow for upgrades
    const int NumberOfBarrelLayers;     // Default = 3
    const int NumberOfEndcapDisks;      // Default = 2

    //-- make_digis 
    const float theElectronPerADC;     // Gain, number of electrons per adc count.
    const int theAdcFullScale;         // Saturation count, 255=8bit.
    const int theAdcFullScaleStack;    // Saturation count for stack layers, 1=1bit.
    const int theFirstStackLayer;      // The first BPix layer to use theAdcFullScaleStack.
    const float theNoiseInElectrons;   // Noise (RMS) in units of electrons.
    const float theReadoutNoise;       // Noise of the readount chain in elec,
                                 //inludes DCOL-Amp,TBM-Amp, Alt, AOH,OptRec.

    const float theThresholdInE_FPix;  // Pixel threshold in electrons FPix.
    const float theThresholdInE_BPix;  // Pixel threshold in electrons BPix.
    const float theThresholdInE_BPix_L1; // In case the BPix layer1 gets a different threshold

    const double theThresholdSmearing_FPix;
    const double theThresholdSmearing_BPix;
    const double theThresholdSmearing_BPix_L1;

    const double electronsPerVCAL;          // for electrons - VCAL conversion
    const double electronsPerVCAL_Offset;   // in misscalibrate()

    const float theTofLowerCut;             // Cut on the particle TOF
    const float theTofUpperCut;             // Cut on the particle TOF
    const float tanLorentzAnglePerTesla_FPix;   //FPix Lorentz angle tangent per Tesla
    const float tanLorentzAnglePerTesla_BPix;   //BPix Lorentz angle tangent per Tesla

    const float FPix_p0;
    const float FPix_p1;
    const float FPix_p2;
    const float FPix_p3;
    const float BPix_p0;
    const float BPix_p1;
    const float BPix_p2;
    const float BPix_p3;


    //-- add_noise
    const bool addNoise;
    const bool addChargeVCALSmearing;
    const bool addNoisyPixels;
    const bool fluctuateCharge;
    //-- pixel efficiency
    const bool AddPixelInefficiency;        // bool to read in inefficiencies

    const bool addThresholdSmearing;
        
    //-- calibration smearing
    const bool doMissCalibrate;         // Switch on the calibration smearing
    const float theGainSmearing;        // The sigma of the gain fluctuation (around 1)
    const float theOffsetSmearing;      // The sigma of the offset fluct. (around 0)
    
    // pseudoRadDamage
    const double pseudoRadDamage;       // Decrease the amount off freed charge that reaches the collector
    const double pseudoRadDamageRadius; // Only apply pseudoRadDamage to pixels with radius<=pseudoRadDamageRadius
    // The PDTable
    //HepPDTable *particleTable;
    //ParticleDataTable *particleTable;

    //-- charge fluctuation
    const double tMax;  // The delta production cut, should be as in OSCAR = 30keV
    //                                           cmsim = 100keV

    // The eloss fluctuation class from G4. Is the right place? 
    const std::unique_ptr<SiG4UniversalFluctuation> fluctuate;   // make a pointer
    const std::unique_ptr<GaussianTailNoiseGenerator> theNoiser;

    // To store calibration constants
    const std::map<int,CalParameters,std::less<int> > calmap;


    //-- additional member functions    
    // Private methods
    std::map<int,CalParameters,std::less<int> > initCal() const;
    void primary_ionization( const PSimHit& hit, std::vector<EnergyDepositUnit>& ionization_points) const;
    void drift(const PSimHit& hit,
               const PixelGeomDetUnit *pixdet,
               const GlobalVector& bfield,
               const std::vector<EnergyDepositUnit>& ionization_points,
               std::vector<SignalPoint>& collection_points) const;
    void induce_signal(const PSimHit& hit,
                       const PixelGeomDetUnit *pixdet,
                       const std::vector<SignalPoint>& collection_points);
    void fluctuateEloss(int particleId, float momentum, float eloss, 
                        float length, int NumberOfSegments,
                        float elossVector[]) const;
    void add_noise(const PixelGeomDetUnit *pixdet,
                   float thePixelThreshold);
    void make_digis(float thePixelThresholdInE,
                    uint32_t detID,
                    std::vector<PixelDigi>& digis,
                    std::vector<PixelDigiSimLink>& simlinks,
                    const TrackerTopology *tTopo) const;
    void pixel_inefficiency(const PixelEfficiencies& eff,
                            const PixelGeomDetUnit* pixdet,
                            const TrackerTopology *tTopo);

    void pixel_inefficiency_db(uint32_t detID);

    // access to the gain calibration payloads in the db. Only gets initialized if check_dead_pixels_ is set to true.
    const std::unique_ptr<SiPixelGainCalibrationOfflineSimService> theSiPixelGainCalibrationService_;    
    float missCalibrate(uint32_t detID, int col, int row, float amp) const;  
    LocalVector DriftDirection(const PixelGeomDetUnit* pixdet,
                               const GlobalVector& bfield,
                               const DetId& detId) const;

    void module_killing_conf(uint32_t detID); // remove dead modules using the list in the configuration file PixelDigi_cfi.py
    void module_killing_DB(uint32_t detID);  // remove dead modules uisng the list in the DB

    const PixelEfficiencies pixelEfficiencies_;

   // For random numbers
    const std::unique_ptr<CLHEP::RandFlat> flatDistribution_;
    const std::unique_ptr<CLHEP::RandGaussQ> gaussDistribution_;
    const std::unique_ptr<CLHEP::RandGaussQ> gaussDistributionVCALNoise_;

    // Threshold gaussian smearing:
    const std::unique_ptr<CLHEP::RandGaussQ> smearedThreshold_FPix_;
    const std::unique_ptr<CLHEP::RandGaussQ> smearedThreshold_BPix_;
    const std::unique_ptr<CLHEP::RandGaussQ> smearedThreshold_BPix_L1_;

    double calcQ(float x) const {
      // need erf(x/sqrt2)
      //float x2=0.5*x*x;
      //float a=0.147;
      //double erf=sqrt(1.0f-exp( -1.0f*x2*( (4/M_PI)+a*x2)/(1.0+a*x2)));
      //if (x<0.) erf*=-1.0;
      //return 0.5*(1.0-erf);

      auto xx=std::min(0.5f*x*x,12.5f);
      return 0.5*(1.0-std::copysign(std::sqrt(1.f- unsafe_expf<4>(-xx*(1.f+0.2733f/(1.f+0.147f*xx)) )),x));
    }


};

#endif