//___________________________________________________________________________
Double_t KVChannelVolt::InvertDouble(Double_t volts)
{
   Double_t gain = 1.;
   KVDetector* det = GetDetector();
   if (det)
      gain = det->GetGain();
   Double_t channel = 0;

   if (fReady) {
      if (fPar[2]) {
         // quadratic transfer function
         Double_t c;
         c = fPar[1] * fPar[1] - 4. * fPar[2] * (fPar[0] - gain / gain_ref * volts);
         if (c < 0.0)
            return -1;
         c = (-fPar[1] + TMath::Sqrt(c)) / (2.0 * fPar[2]);
         if (c < 0.0
               && ((-fPar[1] - TMath::Sqrt(c)) / (2.0 * fPar[2])) > 0.0) {
            c = (-fPar[1] - TMath::Sqrt(c)) / (2.0 * fPar[2]);
         }
         channel = c;
      }
      else {
         // linear transfer function
         channel = (gain / gain_ref * volts - fPar[0]) / fPar[1];
      }
   }
   else {
      Warning("Compute", "Parameters not correctly initialized");
   }
   return (Double_t) channel;
}
//___________________________________________________________________________
Double_t KVChannelVolt::Invert(Double_t volts)
{
   //Given the calibrated (or simulated) signal amplitude in volts,
   //calculate the corresponding channel number according to the
   //calibration parameters (useful for filtering simulations).

   Double_t gain = 1.;
   KVDetector* det = GetDetector();
   if (det)
      gain = det->GetGain();
   Int_t channel = 0;

   if (fReady) {
      if (fPar[2]) {
         // quadratic transfer function
         Double_t c;
         c = fPar[1] * fPar[1] - 4. * fPar[2] * (fPar[0] - gain / gain_ref * volts);
         if (c < 0.0)
            return -1;
         c = (-fPar[1] + TMath::Sqrt(c)) / (2.0 * fPar[2]);
         if (c < 0.0
               && ((-fPar[1] - TMath::Sqrt(c)) / (2.0 * fPar[2])) > 0.0) {
            c = (-fPar[1] - TMath::Sqrt(c)) / (2.0 * fPar[2]);
         }
         channel = (Int_t)(c + 0.5);
      } else {
         // linear transfer function
         channel = (Int_t)(0.5 + (gain / gain_ref * volts - fPar[0]) / fPar[1]);
      }
   } else {
      Warning("Compute", "Parameters not correctly initialized");
   }
   return (Double_t) channel;
}
//___________________________________________________________________________
Double_t KVChannelVolt::Compute(Double_t chan) const
{
   Double_t gain = 1.;
   KVDetector* det = GetDetector();
   if (det)
      gain = det->GetGain();
   //Calculate the calibrated signal strength in volts for a given channel number.
   if (fReady) {
      return (fPar[0] + fPar[1] * chan + fPar[2] * chan * chan) * gain_ref / gain;
   } else {
      return 0.;
   }
}