source: trunk/source/processes/electromagnetic/lowenergy/src/G4CrossSectionExcitationBornPartial.cc @ 836

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// $Id: G4CrossSectionExcitationBornPartial.cc,v 1.1 2007/10/15 08:57:54 pia Exp $
// GEANT4 tag $Name:  $
// 
// Contact Author: Maria Grazia Pia (Maria.Grazia.Pia@cern.ch)
//
// Reference: TNS Geant4-DNA paper
// Reference for implementation model: NIM. 155, pp. 145-156, 1978

// History:
// -----------
// Date         Name              Modification
// 28 Apr 2007  M.G. Pia          Created in compliance with design described in TNS paper
//
// -------------------------------------------------------------------

// Class description:
// Geant4-DNA Cross total cross section for electron elastic scattering in water
// Reference: TNS Geant4-DNA paper
// S. Chauvie et al., Geant4 physics processes for microdosimetry simulation:
// design foundation and implementation of the first set of models,
// IEEE Trans. Nucl. Sci., vol. 54, no. 6, Dec. 2007.
// Further documentation available from http://www.ge.infn.it/geant4/dna

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


#include "G4CrossSectionExcitationBornPartial.hh"
#include "G4Track.hh"
#include "G4DynamicParticle.hh"
#include "G4ParticleDefinition.hh"
#include "G4Electron.hh"
#include "G4LogLogInterpolation.hh"

#include "Randomize.hh"

#include <deque>

G4CrossSectionExcitationBornPartial::G4CrossSectionExcitationBornPartial()
{
  table = 0;
  // nLevels = waterExcitation.NumberOfLevels();
}


G4CrossSectionExcitationBornPartial::~G4CrossSectionExcitationBornPartial()
{
  delete table;
}


G4int G4CrossSectionExcitationBornPartial::RandomSelect(G4double k)
{   
  // Lazy initialisation: load cross section tables in memory the first time access to them is required
  
  G4int level = 0;

  if (table == 0)
    {
      // Load tables
      // ---- MGP ---- 
      table = new G4DNACrossSectionDataSet(new G4LogLogInterpolation, eV,(1e-22/3.343)*m*m );
      table->LoadData("dna/sigma_excitation_p_born");
      
      // ---- MGP ---- Temporary
      table->PrintData();
    }

  G4double* valuesBuffer = new G4double[table->NumberOfComponents()];

  const size_t n(table->NumberOfComponents());
  size_t i(n);
  G4double value = 0.;
  
  while (i>0)
    { 
      i--;
      valuesBuffer[i] = table->GetComponent(i)->FindValue(k);
      value += valuesBuffer[i];
    }
  
  value *= G4UniformRand();
  
  i = n;
  
  while (i > 0)
    {
      i--;
      
      if (valuesBuffer[i] > value)
        {
          delete[] valuesBuffer;
          return i;
        }
      value -= valuesBuffer[i];
    }

  // It should never end up here

  // ---- MGP ---- Is the following line really necessary?  
  if (valuesBuffer) delete[] valuesBuffer;

  return level;
}