G4CascadParticle.cc

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// $Id$
//
// 20100112  M. Kelsey -- Remove G4CascadeMomentum, use G4LorentzVector directly
// 20100114  M. Kelsey -- Replace vector<G4Double> position with G4ThreeVector 
// 20101012  M. Kelsey -- Check for negative d2 in getPathToTheNextZone()
// 20110806  M. Kelsey -- Add fill() function to replicate ctor/op=() action
// 20110922  M. Kelsey -- Follow G4InuclParticle::print(ostream&) migration,
//      Add stream argument to print(), add operator<<().
// 20111017  M. Kelsey -- Add check for zero momentum in path calculation.

#include "G4CascadParticle.hh"
#include "G4ios.hh"
#include <cmath>


// Default constructor produces non-functional object

G4CascadParticle::G4CascadParticle()
  : verboseLevel(0), current_zone(-1), current_path(-1.), movingIn(false),
    reflectionCounter(0), reflected(false), generation(-1) {
  if (verboseLevel > 3) {
    G4cout << " >>> G4CascadParticle::G4CascadParticle" << G4endl;
  }
}

// Analogue to operator=() to support filling vectors w/o temporaries

void G4CascadParticle::fill(const G4InuclElementaryParticle& particle, 
                const G4ThreeVector& pos, G4int izone,
                G4double cpath, G4int gen) {
  if (verboseLevel > 3) G4cout << " >>> G4CascadParticle::fill" << G4endl;

  theParticle = particle;
  position = pos;
  current_zone = izone;
  current_path = cpath;
  movingIn = true;
  reflectionCounter = 0;
  reflected = false;
  generation = gen;
}


G4double G4CascadParticle::getPathToTheNextZone(G4double rz_in, 
                        G4double rz_out) {
  if (verboseLevel > 3) {
    G4cout << " >>> G4CascadParticle::getPathToTheNextZone rz_in " << rz_in
       << " rz_out " << rz_out << G4endl;
  }

  const G4LorentzVector& mom = getMomentum();

  G4double path = -1.0;
  G4double rp = mom.vect().dot(position);
  G4double rr = position.mag2();
  G4double pp = mom.vect().mag2();

  if (std::abs(pp) < 1e-9) {    // Cut-off for "at rest" is 1 eV momentum
    if (verboseLevel > 3) G4cout << " at rest; path length is zero" << G4endl;
    return 0.;
  }

  G4double ra = rr - rp * rp / pp;
  pp = std::sqrt(pp);
  G4double ds;
  G4double d2;

  if (verboseLevel > 3) {
    G4cout << " current_zone " << current_zone << " rr " << rr
       << " rp " << rp << " pp " << pp << " ra " << ra << G4endl;
  }

  if (current_zone == 0 || rp > 0.0) {
    d2 = rz_out * rz_out - ra;
    if (d2 > 0.0) {
      ds = 1.0;
      movingIn = false;
    } else {
      d2 = rz_in * rz_in - ra;
      ds = -1.0;
      movingIn = true;
    }
  } else { 
    d2 = rz_in * rz_in - ra;
    if (d2 > 0.0) {
      ds = -1.0;
      movingIn = true;
    } else {
      d2 = rz_out * rz_out - ra;
      ds = 1.0;
      movingIn = false;
    }
  }

  if (verboseLevel > 3) G4cout << " ds " << ds << " d2 " << d2 << G4endl;

  if (d2 < 0.0 && d2 > -1e-6) d2 = 0.;      // Account for round-off

  if (d2 > 0.0) path = ds * std::sqrt(d2) - rp / pp;    // Avoid FPE failure

  return path;    
}

void G4CascadParticle::propagateAlongThePath(G4double path) {
  if (verboseLevel > 3) {
    G4cout << " >>> G4CascadParticle::propagateAlongThePath" << G4endl;
  }

  position += getMomentum().vect().unit()*path;
}


// Proper stream output (just calls print())

std::ostream& operator<<(std::ostream& os, const G4CascadParticle& part) {
  part.print(os);
  return os;
}

void G4CascadParticle::print(std::ostream& os) const {
  os << theParticle << G4endl
     << " zone " << current_zone << " current_path " << current_path
     << " reflectionCounter " << reflectionCounter << G4endl
     << " x " << position.x() << " y " << position.y()
     << " z " << position.z() << G4endl;
}