Sensor.cc

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#include <iostream>
#include <fstream>
#include <cmath>
 
#include "Sensor.hh"
#include "GarfieldConstants.hh"
#include "Plotting.hh"
#include "Numerics.hh"
#include "FundamentalConstants.hh"
 
namespace Garfield {
 
double Sensor::m_signalConversion = ElementaryCharge;
 
Sensor::Sensor()
    : m_lastComponent(-1),
      m_nTimeBins(200),
      m_tStart(0.),
      m_tStep(10.),
      m_nEvents(0),
      m_hasTransferFunction(false),
      m_fTransfer(0),
      m_hasNoiseFunction(false),
      m_fNoise(0),
      m_hasUserArea(false),
      m_xMinUser(0.),
      m_yMinUser(0.),
      m_zMinUser(0.),
      m_xMaxUser(0.),
      m_yMaxUser(0.),
      m_zMaxUser(0.),
      m_debug(false) {
 
  m_className = "Sensor";
 
}
 
ComponentBase* Sensor::GetComponent(const unsigned int i) {
 
  if (i >= m_components.size()) {
    std::cerr << m_className << "::GetComponent:\n";
      std::cerr << "    Component " << i << " does not exist.\n";
      return NULL;  
    };
    return m_components[i].comp;
}
 
void Sensor::ElectricField(const double x, const double y, const double z,
                           double& ex, double& ey, double& ez, double& v,
                           Medium*& medium, int& status) {
 
  ex = ey = ez = v = 0.;
  status = -10;
  medium = NULL;
  double fx, fy, fz, p;
  Medium* med = NULL;
  int stat;
  // Add up electric field contributions from all components.
  const unsigned int nComponents = m_components.size();
  for (unsigned int i = 0; i < nComponents; ++i) {
    m_components[i].comp->ElectricField(x, y, z, fx, fy, fz, p, med, stat);
    if (status != 0) {
      status = stat;
      medium = med;
    }
    if (stat == 0) {
      ex += fx;
      ey += fy;
      ez += fz;
      v += p;
    }
  }
}
 
void Sensor::ElectricField(const double x, const double y, const double z,
                           double& ex, double& ey, double& ez, Medium*& medium,
                           int& status) {
 
  ex = ey = ez = 0.;
  status = -10;
  medium = NULL;
  double fx, fy, fz;
  Medium* med = NULL;
  int stat;
  // Add up electric field contributions from all components.
  const unsigned int nComponents = m_components.size();
  for (unsigned int i = 0; i < nComponents; ++i) {
    m_components[i].comp->ElectricField(x, y, z, fx, fy, fz, med, stat);
    if (status != 0) {
      status = stat;
      medium = med;
    }
    if (stat == 0) {
      ex += fx;
      ey += fy;
      ez += fz;
    }
  }
}
 
void Sensor::MagneticField(const double x, const double y, const double z,
                           double& bx, double& by, double& bz, int& status) {
 
  bx = by = bz = 0.;
  double fx, fy, fz;
  // Add up contributions.
  const unsigned int nComponents = m_components.size();
  for (unsigned int i = 0; i < nComponents; ++i) {
    m_components[i].comp->MagneticField(x, y, z, fx, fy, fz, status);
    if (status != 0) continue;
    bx += fx;
    by += fy;
    bz += fz;
  }
}
 
void Sensor::WeightingField(const double x, const double y, const double z,
                            double& wx, double& wy, double& wz,
                            const std::string& label) {
 
  wx = wy = wz = 0.;
  double fx = 0., fy = 0., fz = 0.;
  // Add up field contributions from all components.
  const unsigned int nElectrodes = m_electrodes.size();
  for (unsigned int i = 0; i < nElectrodes; ++i) {
    if (m_electrodes[i].label == label) {
      fx = fy = fz = 0.;
      m_electrodes[i].comp->WeightingField(x, y, z, fx, fy, fz, label);
      wx += fx;
      wy += fy;
      wz += fz;
    }
  }
}
 
double Sensor::WeightingPotential(const double x, const double y,
                                  const double z, const std::string& label) {
 
  double v = 0.;
  // Add up contributions from all components.
  const unsigned int nElectrodes = m_electrodes.size();
  for (unsigned int i = 0; i < nElectrodes; ++i) {
    if (m_electrodes[i].label == label) {
      v += m_electrodes[i].comp->WeightingPotential(x, y, z, label);
    }
  }
  return v;
}
 
bool Sensor::GetMedium(const double x, const double y, const double z,
                       Medium*& m) {
 
  m = NULL;
 
  // Make sure there is at least one component.
  if (m_lastComponent < 0) return false;
 
  // Check if we are still in the same component as in the previous call.
  m = m_components[m_lastComponent].comp->GetMedium(x, y, z);
  // Cross-check that the medium is defined.
  if (m) return true;
 
  const unsigned int nComponents = m_components.size();
  for (unsigned int i = 0; i < nComponents; ++i) {
    m = m_components[i].comp->GetMedium(x, y, z);
    // Cross-check that the medium is defined.
    if (m) {
      m_lastComponent = i;
      return true;
    }
  }
  return false;
}
 
bool Sensor::SetArea() {
 
  if (!GetBoundingBox(m_xMinUser, m_yMinUser, m_zMinUser, m_xMaxUser,
                      m_yMaxUser, m_zMaxUser)) {
    std::cerr << m_className << "::SetArea:\n";
    std::cerr << "    Bounding box is not known.\n";
    return false;
  }
 
  std::cout << m_className << "::SetArea:\n";
  std::cout << "    " << m_xMinUser << " < x [cm] < " << m_xMaxUser << "\n";
  std::cout << "    " << m_yMinUser << " < y [cm] < " << m_yMaxUser << "\n";
  std::cout << "    " << m_zMinUser << " < z [cm] < " << m_zMaxUser << "\n";
  if (std::isinf(m_xMinUser) || std::isinf(m_xMaxUser)) {
    std::cerr << m_className << "::SetArea:\n";
    std::cerr << "    Warning: infinite x-range\n";
  }
  if (std::isinf(m_yMinUser) || std::isinf(m_yMaxUser)) {
    std::cerr << m_className << "::SetArea:\n";
    std::cerr << "    Warning: infinite x-range\n";
  }
  if (std::isinf(m_zMinUser) || std::isinf(m_zMaxUser)) {
    std::cerr << m_className << "::SetArea:\n";
    std::cerr << "    Warning: infinite x-range\n";
  }
  m_hasUserArea = true;
  return true;
}
 
bool Sensor::SetArea(const double xmin, const double ymin, const double zmin,
                     const double xmax, const double ymax, const double zmax) {
 
  if (fabs(xmax - xmin) < Small || fabs(ymax - ymin) < Small ||
      fabs(zmax - zmin) < Small) {
    std::cerr << m_className << "::SetArea:\n";
    std::cerr << "    Invalid range.\n";
    return false;
  }
 
  m_xMinUser = xmin;
  m_yMinUser = ymin;
  m_zMinUser = zmin;
  m_xMaxUser = xmax;
  m_yMaxUser = ymax;
  m_zMaxUser = zmax;
 
  if (xmin > xmax) {
    m_xMinUser = xmax;
    m_xMaxUser = xmin;
  }
  if (ymin > ymax) {
    m_yMinUser = ymax;
    m_yMaxUser = ymin;
  }
  if (zmin > zmax) {
    m_zMinUser = zmax;
    m_zMaxUser = zmin;
  }
  m_hasUserArea = true;
  return true;
}
 
bool Sensor::GetArea(double& xmin, double& ymin, double& zmin, double& xmax,
                     double& ymax, double& zmax) {
 
  if (m_hasUserArea) {
    xmin = m_xMinUser;
    ymin = m_yMinUser;
    zmin = m_zMinUser;
    xmax = m_xMaxUser;
    ymax = m_yMaxUser;
    zmax = m_zMaxUser;
    return true;
  }
 
  // User area bounds are not (yet) defined.
  // Get the bounding box of the sensor.
  if (!SetArea()) return false;
 
  xmin = m_xMinUser;
  ymin = m_yMinUser;
  zmin = m_zMinUser;
  xmax = m_xMaxUser;
  ymax = m_yMaxUser;
  zmax = m_zMaxUser;
 
  return true;
}
 
bool Sensor::IsInArea(const double x, const double y, const double z) {
 
  if (!m_hasUserArea) {
    if (!SetArea()) {
      std::cerr << m_className << "::IsInArea:\n";
      std::cerr << "    User area cannot be established.\n";
      return false;
    }
    m_hasUserArea = true;
  }
 
  if (x >= m_xMinUser && x <= m_xMaxUser && y >= m_yMinUser &&
      y <= m_yMaxUser && z >= m_zMinUser && z <= m_zMaxUser) {
    return true;
  }
 
  if (m_debug) {
    std::cout << m_className << "::IsInArea:\n" << std::endl;
    std::cout << "    (" << x << ", " << y << ", " << z << ") "
              << " is outside.\n";
  }
  return false;
}
 
bool Sensor::IsWireCrossed(const double x0, const double y0, const double z0,
                           const double x1, const double y1, const double z1,
                           double& xc, double& yc, double& zc) {
  const unsigned int nComponents = m_components.size();
  for (unsigned int i = 0; i < nComponents; ++i) {
    if (m_components[i].comp->IsWireCrossed(x0, y0, z0, 
                                            x1, y1, z1, xc, yc, zc)) {
      return true;
    }
  }
  return false;
}
 
bool Sensor::IsInTrapRadius(const double q0, const double x0, 
                            const double y0, double z0, double& xw,
                            double& yw, double& rw) {
 
  const unsigned int nComponents = m_components.size();
  for (unsigned int i = 0; i < nComponents; ++i) {
    if (m_components[i].comp->IsInTrapRadius(q0, x0, y0, z0, xw, yw, rw)) {
      return true;
    }
  }
  return false;
}
 
void Sensor::AddComponent(ComponentBase* comp) {
 
  if (!comp) {
    std::cerr << m_className << "::AddComponent:\n    Null pointer.\n";
    return;
  }
 
  component newComponent;
  newComponent.comp = comp;
  m_components.push_back(newComponent);
  if (m_components.size() == 1) m_lastComponent = 0;
}
 
void Sensor::AddElectrode(ComponentBase* comp, const std::string& label) {
 
  if (!comp) {
    std::cerr << m_className << "::AddElectrode:\n    Null pointer.\n";
    return;
  }
  const unsigned int nElectrodes = m_electrodes.size();
  for (unsigned int i = 0; i < nElectrodes; ++i) {
    if (m_electrodes[i].label == label) {
      std::cout << m_className << "::AddElectrode:\n";
      std::cout << "    Warning: An electrode with label \"" << label
                << "\" exists already.\n";
      std::cout << "    Weighting fields will be summed up.\n";
      break;
    }
  }
 
  electrode newElectrode;
  newElectrode.comp = comp;
  newElectrode.label = label;
  m_electrodes.push_back(newElectrode);
  m_electrodes.back().signal.resize(m_nTimeBins);
  m_electrodes.back().electronsignal.resize(m_nTimeBins);
  m_electrodes.back().ionsignal.resize(m_nTimeBins);
  std::cout << m_className << "::AddElectrode:\n";
  std::cout << "    Added readout electrode \"" << label << "\".\n";
  std::cout << "    All signals are reset.\n";
  ClearSignal();
}
 
void Sensor::Clear() {
 
  m_components.clear();
  m_lastComponent = -1;
  m_electrodes.clear();
  m_nTimeBins = 200;
  m_tStart = 0.;
  m_tStep = 10.;
  m_nEvents = 0;
  m_hasUserArea = false;
}
 
bool Sensor::GetVoltageRange(double& vmin, double& vmax) {
 
  // We don't know the range yet.
  bool set = false;
  // Loop over the components.
  double umin, umax;
  const unsigned int nComponents = m_components.size();
  for (unsigned int i = 0; i < nComponents; ++i) {
    if (!m_components[i].comp->GetVoltageRange(umin, umax)) continue;
    if (set) {
      if (umin < vmin) vmin = umin;
      if (umax > vmax) vmax = umax;
    } else {
      vmin = umin;
      vmax = umax;
      set = true;
    }
  }
 
  // Warn if we still don't know the range.
  if (!set) {
    std::cerr << m_className << "::GetVoltageRange:\n";
    std::cerr << "    Sensor voltage range not known.\n";
    vmin = vmax = 0.;
    return false;
  }
 
  if (m_debug) {
    std::cout << m_className << "::GetVoltageRange:\n";
    std::cout << "    Voltage range " << vmin << " < V < " << vmax << ".\n";
  }
  return true;
}
 
void Sensor::ClearSignal() {
 
  const unsigned int nElectrodes = m_electrodes.size();
  for (unsigned int i = 0; i < nElectrodes; ++i) {
    m_electrodes[i].charge = 0.;
    for (int j = m_nTimeBins; j--;) {
      m_electrodes[i].signal[j] = 0.;
      m_electrodes[i].electronsignal[j] = 0.;
      m_electrodes[i].ionsignal[j] = 0.;
    }
  }
  m_nEvents = 0;
}
 
void Sensor::AddSignal(const double q, const double t, const double dt,
                       const double x, const double y, const double z,
                       const double vx, const double vy, const double vz) {
  // Get the time bin.
  if (t < m_tStart || dt <= 0.) {
    if (m_debug) {
      std::cerr << m_className << "::AddSignal:\n";
      if (t < m_tStart) std::cerr << "    Time " << t << " out of range.\n";
      if (dt <= 0.) std::cerr << "    Time step < 0.\n";
    }
    return;
  }
  const int bin = int((t - m_tStart) / m_tStep);
  // Check if the starting time is outside the range
  if (bin < 0 || bin >= (int)m_nTimeBins) {
    if (m_debug) {
      std::cerr << m_className << "::AddSignal:\n";
      std::cerr << "    Bin " << bin << " out of range.\n";
    }
    return;
  }
  if (m_nEvents <= 0) m_nEvents = 1;
 
  double wx = 0., wy = 0., wz = 0.;
  if (m_debug) {
    std::cout << m_className << "::AddSignal:\n";
    std::cout << "    Time: " << t << "\n";
    std::cout << "    Step: " << dt << "\n";
    std::cout << "    Charge: " << q << "\n";
    std::cout << "    Velocity: (" << vx << ", " << vy << ", " << vz << ")\n";
  }
  const unsigned int nElectrodes = m_electrodes.size();
  for (unsigned int i = 0; i < nElectrodes; ++i) {
    // Calculate the weighting field for this electrode
    m_electrodes[i].comp->WeightingField(x, y, z, wx, wy, wz, 
                                         m_electrodes[i].label);
    // Calculate the induced current
    const double cur = -q * (wx * vx + wy * vy + wz * vz);
    if (m_debug) {
      std::cout << "    Electrode " << m_electrodes[i].label << ":\n";
      std::cout << "      Weighting field: (" << wx << ", " << wy << ", " << wz
                << ")\n";
      std::cout << "      Induced charge: " << cur* dt << "\n";
    }
    double delta = m_tStart + (bin + 1) * m_tStep - t;
    // Check if the provided timestep extends over more than one time bin
    if (dt > delta) {
      m_electrodes[i].signal[bin] += cur * delta;
      if (q < 0) {
        m_electrodes[i].electronsignal[bin] += cur * delta;
      } else {
        m_electrodes[i].ionsignal[bin] += cur * delta;
      }
      delta = dt - delta;
      unsigned int j = 1;
      while (delta > m_tStep && bin + j < m_nTimeBins) {
        m_electrodes[i].signal[bin + j] += cur * m_tStep;
        if (q < 0) {
          m_electrodes[i].electronsignal[bin + j] += cur * m_tStep;
        } else {
          m_electrodes[i].ionsignal[bin + j] += cur * m_tStep;
        }
        delta -= m_tStep;
        ++j;
      }
      if (bin + j < m_nTimeBins) {
        m_electrodes[i].signal[bin + j] += cur * delta;
        if (q < 0) {
          m_electrodes[i].electronsignal[bin + j] += cur * delta;
        } else {
          m_electrodes[i].ionsignal[bin + j] += cur * delta;
        }
      }
    } else {
      m_electrodes[i].signal[bin] += cur * dt;
      if (q < 0) {
        m_electrodes[i].electronsignal[bin] += cur * dt;
      } else {
        m_electrodes[i].ionsignal[bin] += cur * dt;
      }
    }
  }
}
 
void Sensor::AddInducedCharge(const double q, const double x0, const double y0,
                              const double z0, const double x1, const double y1,
                              const double z1) {
 
  if (m_debug) std::cout << m_className << "::AddInducedCharge:\n";
  double w0 = 0., w1 = 0.;
  const unsigned int nElectrodes = m_electrodes.size();
  for (unsigned int i = 0; i < nElectrodes; ++i) {
    // Calculate the weighting potential at the starting point.
    w0 = m_electrodes[i]
             .comp->WeightingPotential(x0, y0, z0, m_electrodes[i].label);
    // Calculate the weighting potential at the end point.
    w1 = m_electrodes[i]
             .comp->WeightingPotential(x1, y1, z1, m_electrodes[i].label);
    m_electrodes[i].charge += q * (w1 - w0);
    if (m_debug) {
      std::cout << "    Electrode " << m_electrodes[i].label << ":\n";
      std::cout << "      Weighting potential at (" << x0 << ", " << y0 << ", "
                << z0 << "): " << w0 << "\n";
      std::cout << "      Weighting potential at (" << x1 << ", " << y1 << ", "
                << z1 << "): " << w1 << "\n";
      std::cout << "      Induced charge: " << m_electrodes[i].charge << "\n";
    }
  }
}
 
void Sensor::SetTimeWindow(const double tstart, const double tstep,
                           const unsigned int nsteps) {
 
  m_tStart = tstart;
  if (tstep <= 0.) {
    std::cerr << m_className << "::SetTimeWindow:\n";
    std::cerr << "    Starting time out of range.\n";
  } else {
    m_tStep = tstep;
  }
 
  if (nsteps == 0) {
    std::cerr << m_className << "::SetTimeWindow:\n";
    std::cerr << "    Number of time bins out of range.\n";
  } else {
    m_nTimeBins = nsteps;
  }
 
  if (m_debug) {
    std::cout << m_className << "::SetTimeWindow:\n";
    std::cout << "    " << m_tStart << " < t [ns] < "
              << m_tStart + m_nTimeBins* m_tStep << "\n";
    std::cout << "    Step size: " << m_tStep << " ns\n";
  }
 
  std::cout << m_className << "::SetTimeWindow:\n";
  std::cout << "    Resetting all signals.\n";
  const unsigned int nElectrodes = m_electrodes.size();
  for (unsigned int i = 0; i < nElectrodes; ++i) {
    m_electrodes[i].signal.assign(m_nTimeBins, 0.);
    m_electrodes[i].electronsignal.assign(m_nTimeBins, 0.);
    m_electrodes[i].ionsignal.assign(m_nTimeBins, 0.);
  }
  m_nEvents = 0;
}
 
double Sensor::GetElectronSignal(const std::string& label, 
                                 const unsigned int bin) {
 
  if (m_nEvents == 0) return 0.;
  if (bin >= m_nTimeBins) return 0.;
  double sig = 0.;
  const unsigned int nElectrodes = m_electrodes.size();
  for (unsigned int i = 0; i < nElectrodes; ++i) {
    if (m_electrodes[i].label == label)
      sig += m_electrodes[i].electronsignal[bin];
  }
  if (m_debug) {
    std::cout << m_className << "::GetElectronSignal:\n";
    std::cout << "    Electrode: " << label << "\n";
    std::cout << "    Bin: " << bin << "\n";
    std::cout << "    ElectronSignal: " << sig / m_tStep << "\n";
  }
  return m_signalConversion * sig / (m_nEvents * m_tStep);
}
 
double Sensor::GetIonSignal(const std::string& label, const unsigned int bin) {
 
  if (m_nEvents == 0) return 0.;
  if (bin >= m_nTimeBins) return 0.;
  double sig = 0.;
  const unsigned int nElectrodes = m_electrodes.size();
  for (unsigned int i = 0; i < nElectrodes; ++i) {
    if (m_electrodes[i].label == label) sig += m_electrodes[i].ionsignal[bin];
  }
  if (m_debug) {
    std::cout << m_className << "::GetIonSignal:\n";
    std::cout << "    Electrode: " << label << "\n";
    std::cout << "    Bin: " << bin << "\n";
    std::cout << "    IonSignal: " << sig / m_tStep << "\n";
  }
  return m_signalConversion * sig / (m_nEvents * m_tStep);
}
 
double Sensor::GetSignal(const std::string& label, const unsigned int bin) {
 
  if (m_nEvents == 0) return 0.;
  if (bin >= m_nTimeBins) return 0.;
  double sig = 0.;
  const unsigned int nElectrodes = m_electrodes.size();
  for (unsigned int i = 0; i < nElectrodes; ++i) {
    if (m_electrodes[i].label == label) sig += m_electrodes[i].signal[bin];
  }
  if (m_debug) {
    std::cout << m_className << "::GetSignal:\n";
    std::cout << "    Electrode: " << label << "\n";
    std::cout << "    Bin: " << bin << "\n";
    std::cout << "    Signal: " << sig / m_tStep << "\n";
  }
  return m_signalConversion * sig / (m_nEvents * m_tStep);
}
 
double Sensor::GetInducedCharge(const std::string& label) {
 
  if (m_nEvents == 0) return 0.;
  double charge = 0.;
  const unsigned int nElectrodes = m_electrodes.size();
  for (unsigned int i = 0; i < nElectrodes; ++i) {
    if (m_electrodes[i].label == label) charge += m_electrodes[i].charge;
  }
  if (m_debug) {
    std::cout << m_className << "::GetInducedCharge:\n";
    std::cout << "    Electrode: " << label << "\n";
    std::cout << "    Charge: " << charge / m_tStep << "\n";
  }
 
  return charge / m_nEvents;
}
 
void Sensor::SetTransferFunction(double (*f)(double t)) {
 
  if (!f) {
    std::cerr << m_className << "::SetTransferFunction:\n    Null pointer.\n";
    return;
  }
  m_fTransfer = f;
  m_hasTransferFunction = true;
  m_transferFunctionTimes.clear();
  m_transferFunctionValues.clear();
}
 
void Sensor::SetTransferFunction(const std::vector<double>& times,
                                 const std::vector<double>& values) {
 
  if (times.empty() || values.empty()) {
    std::cerr << m_className << "::SetTransferFunction:\n";
    std::cerr << "    Time and value vectors must not be empty.\n";
    return;
  } else if (times.size() != values.size()) {
    std::cerr << m_className << "::SetTransferFunction:\n";
    std::cerr << "    Time and value vectors must have same size.\n";
    return;
  }
  m_transferFunctionTimes = times;
  m_transferFunctionValues = values;
  m_fTransfer = NULL;
  m_hasTransferFunction = true;
}
 
double Sensor::InterpolateTransferFunctionTable(double t) {
 
  if (m_transferFunctionTimes.empty() || m_transferFunctionValues.empty()) {
    return 0.;
  }
  // Don't extrapolate beyond the range defined in the table.
  if (t < m_transferFunctionTimes.front() ||
      t > m_transferFunctionTimes.back()) {
    return 0.;
  }
  // Find the proper interval in the table.
  int iLow = 0;
  int iUp = m_transferFunctionTimes.size() - 1;
  int iM;
  while (iUp - iLow > 1) {
    iM = (iUp + iLow) >> 1;
    if (t >= m_transferFunctionTimes[iM]) {
      iLow = iM;
    } else {
      iUp = iM;
    }
  }
  // Linear interpolation.
  return m_transferFunctionValues[iLow] +
         (t - m_transferFunctionTimes[iLow]) *
             (m_transferFunctionValues[iUp] - m_transferFunctionValues[iLow]) /
             (m_transferFunctionTimes[iUp] - m_transferFunctionTimes[iLow]);
}
 
double Sensor::GetTransferFunction(const double t) {
 
  if (!m_hasTransferFunction) return 0.;
  if (m_fTransfer) return m_fTransfer(t);
  return InterpolateTransferFunctionTable(t);
}
 
bool Sensor::ConvoluteSignal() {
 
  if (!m_hasTransferFunction) {
    std::cerr << m_className << "::ConvoluteSignal:\n";
    std::cerr << "    No transfer function available.\n";
    return false;
  }
  if (m_nEvents == 0) {
    std::cerr << m_className << "::ConvoluteSignal:\n";
    std::cerr << "    No signals present.\n";
    return false;
  }
 
  // Set the range where the transfer function is valid.
  double cnvMin = 0.;
  double cnvMax = 1.e10;
 
  std::vector<double> cnvTab(2 * m_nTimeBins, 0.);
  int iOffset = m_nTimeBins;
  // Evaluate the transfer function.
  for (unsigned int i = 0; i < m_nTimeBins; ++i) {
    // Negative time part.
    double t = -i * m_tStep;
    if (t < cnvMin || t > cnvMax) {
      cnvTab[iOffset - i] = 0.;
    } else if (m_fTransfer) {
      cnvTab[iOffset - i] = m_fTransfer(t);
    } else {
      cnvTab[iOffset - i] = InterpolateTransferFunctionTable(t);
    }
    if (i < 1) continue;
    // Positive time part.
    t = i * m_tStep;
    if (t < cnvMin || t > cnvMax) {
      cnvTab[iOffset + i] = 0.;
    } else if (m_fTransfer) {
      cnvTab[iOffset + i] = m_fTransfer(t);
    } else {
      cnvTab[iOffset + i] = InterpolateTransferFunctionTable(t);
    }
  }
 
  std::vector<double> tmpSignal(m_nTimeBins, 0.);
  // Loop over all electrodes.
  const unsigned int nElectrodes = m_electrodes.size();
  for (unsigned int i = 0; i < nElectrodes; ++i) {
    for (unsigned int j = 0; j < m_nTimeBins; ++j) {
      tmpSignal[j] = 0.;
      for (unsigned int k = 0; k < m_nTimeBins; ++k) {
        tmpSignal[j] +=
            m_tStep * cnvTab[iOffset + j - k] * m_electrodes[i].signal[k];
      }
    }
    m_electrodes[i].signal = tmpSignal;
  }
  return true;
}
 
bool Sensor::IntegrateSignal() {
 
  if (m_nEvents == 0) {
    std::cerr << m_className << "::IntegrateSignal:\n";
    std::cerr << "    No signals present.\n";
    return false;
  }
 
  const unsigned int nElectrodes = m_electrodes.size();
  for (unsigned int i = 0; i < nElectrodes; ++i) {
    for (unsigned int j = 0; j < m_nTimeBins; ++j) {
      m_electrodes[i].signal[j] *= m_tStep;
      m_electrodes[i].electronsignal[j] *= m_tStep;
      m_electrodes[i].ionsignal[j] *= m_tStep;
      if (j > 0) {
        m_electrodes[i].signal[j] += m_electrodes[i].signal[j - 1];
        m_electrodes[i].electronsignal[j] +=
            m_electrodes[i].electronsignal[j - 1];
        m_electrodes[i].ionsignal[j] += m_electrodes[i].ionsignal[j - 1];
      }
    }
  }
  return true;
}
 
void Sensor::SetNoiseFunction(double (*f)(double t)) {
 
  if (f == 0) {
    std::cerr << m_className << "::SetNoiseFunction:\n";
    std::cerr << "    Function pointer is null.\n";
    return;
  }
  m_fNoise = f;
  m_hasNoiseFunction = true;
}
 
void Sensor::AddNoise(const bool total, const bool electron, const bool ion) {
 
  if (!m_hasNoiseFunction) {
    std::cerr << m_className << "::AddNoise:\n";
    std::cerr << "    Noise function is not defined.\n";
    return;
  }
  if (m_nEvents == 0) m_nEvents = 1;
 
  const unsigned int nElectrodes = m_electrodes.size();
  for (unsigned int i = 0; i < nElectrodes; ++i) {
    for (unsigned int j = 0; j < m_nTimeBins; ++j) {
      const double t = m_tStart + (j + 0.5) * m_tStep;
      const double noise = m_fNoise(t);
      if (total) m_electrodes[i].signal[j] += noise;
      if (electron) m_electrodes[i].electronsignal[j] += noise;
      if (ion) m_electrodes[i].ionsignal[j] += noise;
    }
  }
}
 
bool Sensor::ComputeThresholdCrossings(const double thr,
                                       const std::string& label, int& n) {
 
  // Reset the list of threshold crossings.
  m_thresholdCrossings.clear();
  m_thresholdLevel = thr;
 
  // Set the interpolation order.
  int iOrder = 1;
 
  if (m_nEvents == 0) {
    std::cerr << m_className << "::ComputeThresholdCrossings:\n";
    std::cerr << "    No signals present.\n";
    return false;
  }
 
  // Compute the total signal.
  std::vector<double> signal(m_nTimeBins, 0.);
  // Loop over the electrodes.
  bool foundLabel = false;
  const unsigned int nElectrodes = m_electrodes.size();
  for (unsigned int j = 0; j < nElectrodes; ++j) {
    if (m_electrodes[j].label == label) {
      foundLabel = true;
      for (unsigned int i = 0; i < m_nTimeBins; ++i) {
        signal[i] += m_electrodes[j].signal[i];
      }
    }
  }
  if (!foundLabel) {
    std::cerr << m_className << "::ComputeThresholdCrossings:\n";
    std::cerr << "    Electrode " << label << " not found.\n";
    return false;
  }
  const double scale = m_signalConversion / (m_nEvents * m_tStep);
  for (unsigned int i = 0; i < m_nTimeBins; ++i) signal[i] *= scale;
 
  // Establish the range.
  double vMin = signal[0];
  double vMax = signal[0];
  for (unsigned int i = 0; i < m_nTimeBins; ++i) {
    if (signal[i] < vMin) vMin = signal[i];
    if (signal[i] > vMax) vMax = signal[i];
  }
  if (thr < vMin && thr > vMax) {
    if (m_debug) {
      std::cout << m_className << "::ComputeThresholdCrossings:\n";
      std::cout << "    Threshold outside the range [" << vMin << ", " << vMax
                << "]\n";
    }
    return true;
  }
 
  // Check for rising edges.
  bool rise = true;
  bool fall = false;
 
  while (rise || fall) {
    if (m_debug) {
      if (rise) {
        std::cout << m_className << "::ComputeThresholdCrossings:\n";
        std::cout << "    Hunting for rising edges.\n";
      } else if (fall) {
        std::cout << m_className << "::ComputeThresholdCrossings:\n";
        std::cout << "    Hunting for falling edges.\n";
      }
    }
    // Initialise the vectors.
    std::vector<double> times;
    std::vector<double> values;
    times.push_back(m_tStart);
    values.push_back(signal[0]);
    int nValues = 1;
    // Scan the signal.
    for (unsigned int i = 1; i < m_nTimeBins; ++i) {
      // Compute the vector element.
      const double tNew = m_tStart + i * m_tStep;
      const double vNew = signal[i];
      // If still increasing or decreasing, add to the vector.
      if ((rise && vNew > values.back()) || (fall && vNew < values.back())) {
        times.push_back(tNew);
        values.push_back(vNew);
        ++nValues;
        // Otherwise see whether we crossed the threshold level.
      } else if ((values[0] - thr) * (thr - values.back()) >= 0. &&
                 nValues > 1 && ((rise && values.back() > values[0]) ||
                                 (fall && values.back() < values[0]))) {
        // Compute the crossing time.
        double tcr = Numerics::Divdif(times, values, nValues, thr, iOrder);
        thresholdCrossing newCrossing;
        newCrossing.time = tcr;
        newCrossing.rise = rise;
        m_thresholdCrossings.push_back(newCrossing);
        times.clear();
        values.clear();
        times.push_back(tNew);
        values.push_back(vNew);
        nValues = 1;
      } else {
        // No crossing, simply reset the vector.
        times.clear();
        values.clear();
        times.push_back(tNew);
        values.push_back(vNew);
        nValues = 1;
      }
    }
    // Check the final vector.
    if ((values[0] - thr) * (thr - values.back()) >= 0. && nValues > 1 &&
        ((rise && values.back() > values[0]) ||
         (fall && values.back() < values[0]))) {
      double tcr = Numerics::Divdif(times, values, nValues, thr, iOrder);
      thresholdCrossing newCrossing;
      newCrossing.time = tcr;
      newCrossing.rise = rise;
      m_thresholdCrossings.push_back(newCrossing);
    }
    if (rise) {
      rise = false;
      fall = true;
    } else if (fall) {
      rise = fall = false;
    }
  }
  n = m_thresholdCrossings.size();
 
  if (m_debug) {
    std::cout << m_className << "::ComputeThresholdCrossings:\n";
    std::cout << "    Found " << n << " crossings.\n";
    if (n > 0) std::cout << "      Time  [ns]    Direction\n";
    for (int i = 0; i < n; ++i) {
      std::cout << "      " << m_thresholdCrossings[i].time << "      ";
      if (m_thresholdCrossings[i].rise) {
        std::cout << "rising\n";
      } else {
        std::cout << "falling\n";
      }
    }
  }
  // Seems to have worked.
  return true;
}
 
bool Sensor::GetThresholdCrossing(const unsigned int i, double& time, 
                                  double& level, bool& rise) const {
 
  level = m_thresholdLevel;
 
  if (i >= m_thresholdCrossings.size()) {
    std::cerr << m_className << "::GetThresholdCrossing:\n";
    std::cerr << "    Index (" << i << ") out of range.\n";
    time = m_tStart + m_nTimeBins * m_tStep;
    return false;
  }
 
  time = m_thresholdCrossings[i].time;
  rise = m_thresholdCrossings[i].rise;
  return true;
}
 
bool Sensor::GetBoundingBox(double& xmin, double& ymin, double& zmin,
                            double& xmax, double& ymax, double& zmax) {
 
  // We don't know the range yet
  bool set = false;
  // Loop over the fields
  double x0, y0, z0, x1, y1, z1;
  const unsigned int nComponents = m_components.size();
  for (unsigned int i = 0; i < nComponents; ++i) {
    if (!m_components[i].comp->GetBoundingBox(x0, y0, z0, x1, y1, z1)) continue;
    if (set) {
      if (x0 < xmin) xmin = x0;
      if (y0 < ymin) ymin = y0;
      if (z0 < zmin) zmin = z0;
      if (x1 > xmax) xmax = x1;
      if (y1 > ymax) ymax = y1;
      if (z1 > zmax) zmax = z1;
    } else {
      xmin = x0;
      ymin = y0;
      zmin = z0;
      xmax = x1;
      ymax = y1;
      zmax = z1;
      set = true;
    }
  }
 
  // Warn if we still don't know the range
  if (!set) {
    std::cerr << m_className << "::GetBoundingBox:\n";
    std::cerr << "    Sensor bounding box not known.\n";
    xmin = 0.;
    ymin = 0.;
    zmin = 0.;
    xmax = 0.;
    ymax = 0.;
    zmax = 0.;
    return false;
  }
 
  if (m_debug) {
    std::cout << m_className << "::GetBoundingBox:\n";
    std::cout << "    " << xmin << " < x [cm] < " << xmax << "\n";
    std::cout << "    " << ymin << " < y [cm] < " << ymax << "\n";
    std::cout << "    " << zmin << " < z [cm] < " << zmax << "\n";
  }
  return true;
}
}