G4CascadeSampler.icc

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#ifndef G4CASCADE_SAMPLER_ICC
#define G4CASCADE_SAMPLER_ICC
// $Id: G4CascadeSampler.icc 66241 2012-12-13 18:34:42Z gunter $
//
// 20100506 M. Kelsey -- Move functionity of G4CascadeChannel here,
//         use as base class to G4CascadeFunctions<T>.
// 20100512 M. Kelsey -- Move implementation to .icc with templating
// 20100803 M. Kelsey -- Add print function for debugging.
// 20101019 M. Kelsey -- CoVerity report: recursive #include
// 20110728 M. Kelsey -- Fix Coverity #20231, recursive #include
// 20110923 M. Kelsey -- Add optional ostream& argument to print(), pass
//         to interpolator.
// 20120608  M. Kelsey -- Fix variable-name "shadowing" compiler warnings.

#include "Randomize.hh"
#include <iostream>
#include <vector>


template <int NBINS, int NMULT> inline
G4double G4CascadeSampler<NBINS,NMULT>::
findCrossSection(double ke,
            const G4double (&xsec)[energyBins]) const {
  return interpolator.interpolate(ke, xsec);
}

template <int NBINS, int NMULT> inline
G4int G4CascadeSampler<NBINS,NMULT>::
findMultiplicity(G4double ke,
            const G4double xmult[][energyBins]) const {
  fillSigmaBuffer(ke, xmult);
  return sampleFlat() + 2; // Convert array index to actual mult (2 to 7)
}

template <int NBINS, int NMULT> inline
G4int G4CascadeSampler<NBINS,NMULT>::
findFinalStateIndex(G4int mult, G4double ke, const G4int index[],
               const G4double xsec[][energyBins]) const {
  G4int start = index[mult-2];
  G4int stop = index[mult-1];
  if (stop-start <= 1) return start;       // Avoid unnecessary work

  fillSigmaBuffer(ke, xsec, start, stop);
  return sampleFlat();
}

// Optional start/stop arguments default to multiplicity arrays
template <int NBINS, int NMULT> inline
void G4CascadeSampler<NBINS,NMULT>::
fillSigmaBuffer(G4double ke, const G4double x[][energyBins],
           G4int startBin, G4int stopBin) const {
  sigmaBuf.clear();
  if (stopBin-startBin <= 1) return;       // Avoid unnecessary work

  // NOTE:  push_back() must be used to ensure that size() gets set!
  sigmaBuf.reserve(stopBin-startBin);
  for(G4int i = startBin; i < stopBin; i++)
    sigmaBuf.push_back(interpolator.interpolate(ke, x[i]));
}


template <int NBINS, int NMULT> inline
G4int G4CascadeSampler<NBINS,NMULT>::sampleFlat() const {
  G4int nbins = sigmaBuf.size();
  if (nbins <= 1) return 0;                // Avoid unnecessary work

#ifdef G4CASCADE_DEBUG_SAMPLER
  G4cout << "G4CascadeSampler::sampleFlat() has " << nbins << "bins:" << G4endl;
  for (G4int sbi=0; sbi<nbins; sbi++) G4cout << " " << sigmaBuf[sbi];
  G4cout << G4endl;
#endif

  G4int i;
  G4double fsum = 0.;
  for (i = 0; i < nbins; i++) fsum += sigmaBuf[i];
#ifdef G4CASCADE_DEBUG_SAMPLER
  G4cout << " buffer total (fsum) " << fsum;
#endif
  fsum *= G4UniformRand();
#ifdef G4CASCADE_DEBUG_SAMPLER
  G4cout << " *random-scale " << fsum << G4endl;
#endif

  G4double partialSum = 0.0;
  for (i = 0; i < nbins; i++) {
    partialSum += sigmaBuf[i];
    if (fsum < partialSum) return i;       // Breaks out of loop automatically
  }

  return 0;        // Is this right?  Shouldn't it return maximum, not minimum?
}


template <int NBINS, int NMULT> inline
void G4CascadeSampler<NBINS,NMULT>::print(std::ostream& os) const {
  interpolator.printBins(os);
}

#endif     /* G4CASCADE_SAMPLER_ICC */