TFCS2DFunctionLateralShapeParametrization.cxx

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/*
  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
*/
 
#include "CLHEP/Random/RandFlat.h"
#include "CLHEP/Random/RandPoisson.h"
 
#include "ISF_FastCaloSimEvent/TFCS2DFunctionLateralShapeParametrization.h"
#include "ISF_FastCaloSimEvent/FastCaloSim_CaloCell_ID.h"
#include "ISF_FastCaloSimEvent/TFCSSimulationState.h"
#include "ISF_FastCaloSimEvent/TFCSExtrapolationState.h"
 
#include "TFile.h"
#include "TMath.h"
#include "TH2.h"
 
#include "HepPDT/ParticleData.hh"
#include "HepPDT/ParticleDataTable.hh"
 
//=============================================
//======= TFCS2DFunctionLateralShapeParametrization =========
//=============================================
 
TFCS2DFunctionLateralShapeParametrization::
    TFCS2DFunctionLateralShapeParametrization(const char *name,
                                              const char *title)
    : TFCSLateralShapeParametrizationHitBase(name, title), m_function(nullptr),
      m_nhits(0) {
  TFCS2DFunctionLateralShapeParametrization::reset_phi_symmetric();
}
 
TFCS2DFunctionLateralShapeParametrization::
    ~TFCS2DFunctionLateralShapeParametrization() {
  if (m_function)
    delete m_function;
  m_function = nullptr;
}
 
double TFCS2DFunctionLateralShapeParametrization::get_sigma2_fluctuation(
    TFCSSimulationState & /*simulstate*/, const TFCSTruthState * /*truth*/,
    const TFCSExtrapolationState * /*extrapol*/) const {
  return 1.0 / m_nhits;
}
 
int TFCS2DFunctionLateralShapeParametrization::get_number_of_hits(
    TFCSSimulationState &simulstate, const TFCSTruthState * /*truth*/,
    const TFCSExtrapolationState * /*extrapol*/) const {
  if (!simulstate.randomEngine()) {
    return -1;
  }
 
  return CLHEP::RandPoisson::shoot(simulstate.randomEngine(), m_nhits);
}
 
void TFCS2DFunctionLateralShapeParametrization::set_number_of_hits(
    float nhits) {
  m_nhits = nhits;
}
 
FCSReturnCode TFCS2DFunctionLateralShapeParametrization::simulate_hit(
    Hit &hit, TFCSSimulationState &simulstate, const TFCSTruthState *truth,
    const TFCSExtrapolationState * /*extrapol*/) {
  if (!simulstate.randomEngine()) {
    return FCSFatal;
  }
  if (!m_function) {
    return FCSFatal;
  }
 
  const int pdgId = truth->pdgid();
  const double charge = HepPDT::ParticleID(pdgId).charge();
 
  const int cs = calosample();
  const double center_eta = hit.center_eta();
  const double center_phi = hit.center_phi();
  const double center_r = hit.center_r();
  const double center_z = hit.center_z();
 
  if (TMath::IsNaN(center_r) or TMath::IsNaN(center_z) or
      TMath::IsNaN(center_eta) or
      TMath::IsNaN(center_phi)) { // Check if extrapolation fails
    return FCSFatal;
  }
 
  float alpha, r, rnd1, rnd2;
  rnd1 = CLHEP::RandFlat::shoot(simulstate.randomEngine());
  rnd2 = CLHEP::RandFlat::shoot(simulstate.randomEngine());
  if (is_phi_symmetric()) {
    if (rnd2 >= 0.5) { // Fill negative phi half of shape
      rnd2 -= 0.5;
      rnd2 *= 2;
      m_function->rnd_to_fct(alpha, r, rnd1, rnd2);
      alpha = -alpha;
    } else { // Fill positive phi half of shape
      rnd2 *= 2;
      m_function->rnd_to_fct(alpha, r, rnd1, rnd2);
    }
  } else {
    m_function->rnd_to_fct(alpha, r, rnd1, rnd2);
  }
  if (TMath::IsNaN(alpha) || TMath::IsNaN(r)) {
    ATH_MSG_ERROR("  2D function, #hits=" << m_nhits << " alpha=" << alpha
                                          << " r=" << r << " rnd1=" << rnd1
                                          << " rnd2=" << rnd2);
    alpha = 0;
    r = 0.001;
 
    ATH_MSG_ERROR("  This error could probably be retried");
    return FCSFatal;
  }
 
  float delta_eta_mm = r * cos(alpha);
  float delta_phi_mm = r * sin(alpha);
 
  // Particles with negative eta are expected to have the same shape as those
  // with positive eta after transformation: delta_eta --> -delta_eta
  if (center_eta < 0.)
    delta_eta_mm = -delta_eta_mm;
  // We derive the shower shapes for electrons and positively charged hadrons.
  // Particle with the opposite charge are expected to have the same shower shape
  // after the transformation: delta_phi --> -delta_phi
  if ((charge < 0. && pdgId!=11) || pdgId==-11)
    delta_phi_mm = -delta_phi_mm;
 
  const float dist000 = TMath::Sqrt(center_r * center_r + center_z * center_z);
  const float eta_jakobi = TMath::Abs(2.0 * TMath::Exp(-center_eta) /
                                      (1.0 + TMath::Exp(-2 * center_eta)));
 
  const float delta_eta = delta_eta_mm / eta_jakobi / dist000;
  const float delta_phi = delta_phi_mm / center_r;
 
  hit.setEtaPhiZE(center_eta + delta_eta, center_phi + delta_phi, center_z,
                  hit.E());
 
  ATH_MSG_DEBUG("HIT: E=" << hit.E() << " cs=" << cs << " eta=" << hit.eta()
                          << " phi=" << hit.phi() << " z=" << hit.z()
                          << " r=" << r << " alpha=" << alpha);
 
  return FCSSuccess;
}
 
bool TFCS2DFunctionLateralShapeParametrization::Initialize(TFCS2DFunction *func,
                                                           float nhits) {
  if (!func)
    return false;
  if (m_function)
    delete m_function;
  m_function = func;
 
  if (nhits > 0)
    set_number_of_hits(nhits);
 
  return true;
}
 
void TFCS2DFunctionLateralShapeParametrization::Print(Option_t *option) const {
  TString opt(option);
  bool shortprint = opt.Index("short") >= 0;
  bool longprint = msgLvl(MSG::DEBUG) || (msgLvl(MSG::INFO) && !shortprint);
  TString optprint = opt;
  optprint.ReplaceAll("short", "");
  TFCSLateralShapeParametrizationHitBase::Print(option);
 
  if (longprint) {
    if (is_phi_symmetric()) {
      ATH_MSG_INFO(optprint << "  2D function, #hits=" << m_nhits
                            << " (phi symmetric)");
    } else {
      ATH_MSG_INFO(optprint << "  2D function, #hits=" << m_nhits
                            << " (not phi symmetric)");
    }
  }
}