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//
//
// Author:  Vladimir Ivanchenko (Vladimir.Ivantchenko@cern.ch)
//
// History:
// -----------
// 29 May 2002   VI        Created
//
// -------------------------------------------------------------------

#include "G4LinLogLogInterpolation.hh"

// Constructor

G4LinLogLogInterpolation::G4LinLogLogInterpolation()
{ }

// Destructor

G4LinLogLogInterpolation::~G4LinLogLogInterpolation()
{ }

G4VDataSetAlgorithm* G4LinLogLogInterpolation::Clone() const 
{ return new G4LinLogLogInterpolation; }


G4double G4LinLogLogInterpolation::Calculate(G4double x, G4int bin, 
					  const G4DataVector& points, 
					  const G4DataVector& data) const
{
  //G4cout << "G4LinLogLogInterpolation is performed (2 arguments) " << G4endl;
  G4int nBins = data.size() - 1;
  G4double value = 0.;
  if (x < points[0])
    {
      value = 0.;
    }
  else if (bin < nBins)
    {
      G4double e1 = points[bin];
      G4double e2 = points[bin+1];
      G4double d1 = data[bin];
      G4double d2 = data[bin+1];
      if(d1 > 0.0 && d2 > 0.0) {
        value = (std::log10(d1)*std::log10(e2/x) + std::log10(d2)*std::log10(x/e1)) / std::log10(e2/e1);
        value = std::pow(10.,value);
      } else {
        value = (d1*std::log10(e2/x) + d2*std::log10(x/e1)) / std::log10(e2/e1);
      }
    }
  else
    {
      value = data[nBins];
    }

  return value;
}

G4double G4LinLogLogInterpolation::Calculate(G4double x, G4int bin, 
					  const G4DataVector& points,
                                          const G4DataVector& data,
                                          const G4DataVector& log_points, 
					  const G4DataVector& log_data) const
{
  //G4cout << "G4LinLogLogInterpolation is performed(4 arguments)  " << G4endl;
  G4int nBins = data.size() - 1;
  G4double value = 0.;
  G4double log_x = std::log10(x);
  if (x < points[0])
    {
      value = 0.;
    }
  else if (bin < nBins)
    {
      G4double e1 = points[bin];
      G4double e2 = points[bin+1];
      G4double d1 = data[bin];
      G4double d2 = data[bin+1];      
      G4double log_e1 = log_points[bin];
      G4double log_e2 = log_points[bin+1];
      G4double log_d1 = log_data[bin];
      G4double log_d2 = log_data[bin+1];
      //G4cout << "x = " << x << " , log_x = " << log_x << " , bin = " << bin << G4endl;
      //G4cout << "e1 = " << e1 << " , d1 = " << d1 << G4endl;
      //G4cout << "e2 = " << e2 << " , d2 = " << d2 << G4endl;
      //G4cout << "log_e1 = " << log_e1 << " , log_d1 = " << log_d1 << G4endl;
      //G4cout << "log_e2 = " << log_e2 << " , log_d2 = " << log_d2 <<G4endl;
      if (d1 > 0.0 && d2 > 0.0)
       {
         // Values e1, e2, d1 and d2 are the log values of the corresponding
         // original energy and data values. Simple linear interpolation performed
         // on loagarithmic data should be equivalent to log-log interpolation
         value = log_d1 + (log_d2 - log_d1)*(log_x - log_e1)/(log_e2 - log_e1);

         //G4cout << "Case of normal log-log interpolation" << G4endl;
         //G4cout << "Temp log interpolated value: log_value = " << value << G4endl;

         // Delogarithmize to obtain interpolated value
         value = std::pow(10.,value);

         //G4cout << "Final Interpolated value: " << value << G4endl << G4endl;
       }
     else
       {
        // Case of semi log-log interpolation
        //G4cout << "G4LinLogLogInterpolation - Case of SemiLogInterpolation" << G4endl;
        if (e1 == 0.0) e1 = 1e-300;
        if (e2 == 0.0) e2 = 1e-300;
        value = d1 + (d2 - d1)*(log_x - log_e1)/(log_e2 - log_e1);
        //G4cout << "LinLogInterpolation: Final Interpolated value: " << value << G4endl << G4endl;
       }
    }
  else
    {
      value = data[nBins];
    }
  return value;
}