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// $Id: G4PhysicsVector.icc,v 1.23 2009/11/18 11:42:03 vnivanch Exp $
// GEANT4 tag $Name: global-V09-02-10 $
//
// 
//---------------------------------------------------------------
//      GEANT 4 class source file
//
//  G4PhysicsVector.icc
//
//  Description:
//    A physics vector which has values of energy-loss, cross-section, 
//    and other physics values of a particle in matter in a given 
//    range of the energy, momentum, etc.
//    This class serves as the base class for a vector having various 
//    energy scale, for example like 'log', 'linear', 'free', etc.
//
//---------------------------------------------------------------

inline
 G4double G4PhysicsVector::operator[](const size_t binNumber) const
{
  return dataVector[binNumber];
}

//---------------------------------------------------------------

inline
 G4double G4PhysicsVector::operator()(const size_t binNumber) const
{
  return dataVector[binNumber];
}

//---------------------------------------------------------------

inline
 G4double G4PhysicsVector::Energy(const size_t binNumber) const
{
  return binVector[binNumber];
}

//---------------------------------------------------------------

inline 
 size_t G4PhysicsVector::GetVectorLength() const
{
  return numberOfNodes;
}

//---------------------------------------------------------------

inline
 G4double G4PhysicsVector::LinearInterpolation()
{
  // Linear interpolation is used to get the value. If the give energy
  // is in the highest bin, no interpolation will be Done. Because 
  // there is an extra bin hidden from a user at locBin=numberOfBin, 
  // the following interpolation is valid even the current locBin=
  // numberOfBin-1. 

  G4double intplFactor = (lastEnergy-binVector[lastBin]) 
     / (binVector[lastBin+1]-binVector[lastBin]); // Interpolation factor

  return dataVector[lastBin] +
         ( dataVector[lastBin+1]-dataVector[lastBin] ) * intplFactor;
}

//---------------------------------------------------------------

inline
 G4double G4PhysicsVector::SplineInterpolation()
{
  // Spline interpolation is used to get the value. If the give energy
  // is in the highest bin, no interpolation will be Done. Because 
  // there is an extra bin hidden from a user at locBin=numberOfBin, 
  // the following interpolation is valid even the current locBin=
  // numberOfBin-1. 

  if(0 == secDerivative.size() ) { FillSecondDerivatives(); }

  // check bin value
  G4double x1 = binVector[lastBin];
  G4double x2 = binVector[lastBin+1];
  G4double delta = x2 - x1;

  G4double a = (x2 - lastEnergy)/delta;
  G4double b = (lastEnergy - x1)/delta;
   
  // Final evaluation of cubic spline polynomial for return   
  G4double y1 = dataVector[lastBin];
  G4double y2 = dataVector[lastBin+1];

  G4double res = a*y1 + b*y2 + 
        ( (a*a*a - a)*secDerivative[lastBin] +
          (b*b*b - b)*secDerivative[lastBin+1] )*delta*delta/6.0;

  return res;
}

//---------------------------------------------------------------

inline
 G4double G4PhysicsVector::GetValue(G4double theEnergy, G4bool&) 
{
  return Value(theEnergy);
}

//---------------------------------------------------------------

inline
 G4double G4PhysicsVector::Value(G4double theEnergy) 
{
  // Use cache for speed up - check if the value 'theEnergy' is same as the 
  // last call. If it is same, then use the last bin location. Also the
  // value 'theEnergy' lies between the last energy and low edge of of the 
  // bin of last call, then the last bin location is used.

  if( theEnergy == lastEnergy ) {

  } else if(theEnergy < lastEnergy && theEnergy >= binVector[lastBin]) {
     lastEnergy = theEnergy;
     Interpolation();

  } else if( theEnergy <= edgeMin ) {
     lastBin = 0;
     lastEnergy = edgeMin;
     lastValue  = dataVector[0];

  } else if( theEnergy >= edgeMax ){
     lastBin = numberOfNodes-2;
     lastEnergy = edgeMax;
     lastValue  = dataVector[numberOfNodes-1];

  } else {
     lastBin = FindBinLocation(theEnergy); 
     if(lastBin >= numberOfNodes-1) {lastBin = numberOfNodes-2;} 
     lastEnergy = theEnergy;
     Interpolation();
  }
  return lastValue;        
}

//---------------------------------------------------------------

inline 
 void G4PhysicsVector::Interpolation()
{
  if(useSpline) { lastValue = SplineInterpolation(); }
  else          { lastValue = LinearInterpolation(); }
}

//---------------------------------------------------------------

inline 
 void G4PhysicsVector::PutValue(size_t binNumber, G4double theValue)
{
  dataVector[binNumber] = theValue;
}

//---------------------------------------------------------------

inline 
 G4bool G4PhysicsVector::IsFilledVectorExist() const
{
  G4bool status=false;

  if(numberOfNodes > 0) { status=true; }
  return status;
}

//---------------------------------------------------------------

inline 
 void G4PhysicsVector::PutComment(const G4String& theComment)
{
  comment = theComment;
}

//---------------------------------------------------------------

inline 
 const G4String& G4PhysicsVector::GetComment() const
{
  return comment;
}

//---------------------------------------------------------------

inline 
 G4PhysicsVectorType G4PhysicsVector::GetType() const
{
  return type;
}

//---------------------------------------------------------------

inline 
 void G4PhysicsVector::SetSpline(G4bool val)
{
  useSpline = val;
}