G4LorentzConvertor Class Reference

#include <G4LorentzConvertor.hh>

Public Member Functions
	G4LorentzConvertor ()
	G4LorentzConvertor (const G4LorentzVector &bmom, G4double bmass, const G4LorentzVector &tmom, G4double tmass)
	G4LorentzConvertor (const G4InuclParticle *bullet, const G4InuclParticle *target)
void	setVerbose (G4int vb=0)
void	setBullet (const G4InuclParticle *bullet)
void	setTarget (const G4InuclParticle *target)
void	setBullet (const G4InuclParticle &bullet)
void	setTarget (const G4InuclParticle &target)
void	setBullet (const G4LorentzVector &bmom)
void	setTarget (const G4LorentzVector &bmom)
void	setBullet (const G4LorentzVector &bmom, G4double bmass)
void	setTarget (const G4LorentzVector &tmom, G4double tmass)
void	toTheCenterOfMass ()
void	toTheTargetRestFrame ()
void	fillKinematics ()
G4LorentzVector	backToTheLab (const G4LorentzVector &mom) const
const G4LorentzVector &	getBullet () const
const G4LorentzVector &	getTarget () const
G4double	getKinEnergyInTheTRS () const
G4double	getTotalSCMEnergy () const
G4double	getSCMMomentum () const
G4double	getTRSMomentum () const
G4LorentzVector	rotate (const G4LorentzVector &mom) const
G4LorentzVector	rotate (const G4LorentzVector &mom1, const G4LorentzVector &mom) const
G4bool	reflectionNeeded () const
G4bool	trivial () const
void	printBullet () const
void	printTarget () const

Detailed Description

Definition at line 45 of file G4LorentzConvertor.hh.

Constructor & Destructor Documentation

G4LorentzConvertor::G4LorentzConvertor

(

)

Definition at line 47 of file G4LorentzConvertor.cc.

  : verboseLevel(0), v2(0.), ecm_tot(0.), valong(0.), degenerated(false) {}

G4LorentzConvertor::G4LorentzConvertor	(	const G4LorentzVector &	bmom,
		G4double	bmass,
		const G4LorentzVector &	tmom,
		G4double	tmass
	)

Definition at line 51 of file G4LorentzConvertor.cc.

  : verboseLevel(0), v2(0.), ecm_tot(0.), valong(0.), degenerated(false) {
  setBullet(bmom, bmass);
  setTarget(tmom, tmass);
}

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G4LorentzConvertor::G4LorentzConvertor	(	const G4InuclParticle *	bullet,
		const G4InuclParticle *	target
	)

Definition at line 59 of file G4LorentzConvertor.cc.

  : verboseLevel(0), v2(0.), ecm_tot(0.), valong(0.), degenerated(false) {
  setBullet(bullet);
  setTarget(target);
}

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Member Function Documentation

G4LorentzVector G4LorentzConvertor::backToTheLab

(

const G4LorentzVector &

mom

)

const

Definition at line 135 of file G4LorentzConvertor.cc.

                                                                 {
  if (verboseLevel > 2)
    G4cout << " >>> G4LorentzConvertor::backToTheLab" << G4endl;

  if (verboseLevel > 3)
    G4cout << " at rest: px " << mom.x() << " py " << mom.y() << " pz "
       << mom.z() << " e " << mom.e() << G4endl
       << " v2 " << v2 << G4endl;

  G4LorentzVector mom1 = mom;
  if (v2 > small) mom1.boost(velocity);

  if (verboseLevel > 3)
    G4cout << " at lab: px " << mom1.x() << " py " << mom1.y() << " pz "
       << mom1.z() << G4endl;

  return mom1;
}

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void G4LorentzConvertor::fillKinematics

(

)

Definition at line 113 of file G4LorentzConvertor.cc.

                                        {
  ecm_tot = (target_mom+bullet_mom).m();

  scm_direction = scm_momentum.vect().unit();
  valong = velocity.dot(scm_direction);

  v2 = velocity.mag2();

  G4double pvsq = v2 - valong*valong;       // velocity perp to scm_momentum
  if (verboseLevel > 3) G4cout << " pvsq " << pvsq << G4endl;

  degenerated = (pvsq < small);
  if (degenerated && verboseLevel > 2) 
    G4cout << " degenerated case (already along Z) " << G4endl; 

  if (verboseLevel > 3) {
    G4cout << " v2 " << v2 << " valong " << valong
       << " valong*valong " << valong*valong << G4endl;
  }
}

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const G4LorentzVector& G4LorentzConvertor::getBullet ( ) const

inline

Definition at line 93 of file G4LorentzConvertor.hh.

{ return bullet_mom; }

G4double G4LorentzConvertor::getKinEnergyInTheTRS

(

)

const

Definition at line 157 of file G4LorentzConvertor.cc.

                                                        {
  if (verboseLevel > 2)
    G4cout << " >>> G4LorentzConvertor::getKinEnergyInTheTRS" << G4endl;

  G4LorentzVector bmom = bullet_mom;
  bmom.boost(-target_mom.boostVector());
  return bmom.e()-bmom.m();
}

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G4double G4LorentzConvertor::getSCMMomentum ( ) const

inline

Definition at line 98 of file G4LorentzConvertor.hh.

{ return scm_momentum.rho(); }

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const G4LorentzVector& G4LorentzConvertor::getTarget ( ) const

inline

Definition at line 94 of file G4LorentzConvertor.hh.

{ return target_mom; }

G4double G4LorentzConvertor::getTotalSCMEnergy ( ) const

inline

Definition at line 97 of file G4LorentzConvertor.hh.

{ return ecm_tot; }

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G4double G4LorentzConvertor::getTRSMomentum

(

)

const

Definition at line 166 of file G4LorentzConvertor.cc.

                                                  {
  if (verboseLevel > 2)
    G4cout << " >>> G4LorentzConvertor::getTRSMomentum" << G4endl;

  G4LorentzVector bmom = bullet_mom;
  bmom.boost(-target_mom.boostVector());
  return bmom.rho();
}

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void G4LorentzConvertor::printBullet

(

)

const

Definition at line 289 of file G4LorentzConvertor.cc.

                                           {
  G4cout << " G4LC bullet: px " << bullet_mom.px() << " py " << bullet_mom.py()
     << " pz " << bullet_mom.pz() << " e " << bullet_mom.e()
     << " mass " << bullet_mom.m() << G4endl;
  }

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void G4LorentzConvertor::printTarget

(

)

const

Definition at line 295 of file G4LorentzConvertor.cc.

                                           {
  G4cout << " G4LC target: px " << target_mom.px() << " py " << target_mom.py()
     << " pz " << target_mom.pz() << " e " << target_mom.e()
     << " mass " << target_mom.m() << G4endl;
}

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G4bool G4LorentzConvertor::reflectionNeeded

(

)

const

Definition at line 265 of file G4LorentzConvertor.cc.

                                                  {
  if (verboseLevel > 2)
    G4cout << " >>> G4LorentzConvertor::reflectionNeeded (query)" << G4endl;

  if (verboseLevel > 3) {
    G4cout << " v2 = " << v2 << " SCM z = " << scm_momentum.z()
       << " degenerated? " << degenerated << G4endl;
  }

  if (v2 < small && !degenerated) 
    throw G4HadronicException(__FILE__, __LINE__, "G4LorentzConvertor::reflectionNeeded - return value undefined");

  if (verboseLevel > 2) {
    G4cout << " reflection across XY is"
       << ((v2>=small && (!degenerated || scm_momentum.z()<0.0))?"":" NOT")
       << " needed" << G4endl;
  }

  return (v2>=small && (!degenerated || scm_momentum.z()<0.0));
}

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G4LorentzVector G4LorentzConvertor::rotate

(

const G4LorentzVector &

mom

)

const

Definition at line 175 of file G4LorentzConvertor.cc.

                                                                           {
  if (verboseLevel > 2)
    G4cout << " >>> G4LorentzConvertor::rotate(G4LorentzVector)" << G4endl;

  if (verboseLevel > 3) {
    G4cout << " valong " << valong << " degenerated " << degenerated << G4endl
       << " before rotation: px " << mom.x() << " py " << mom.y()
       << " pz " << mom.z() << G4endl;
  }

  G4LorentzVector mom_rot = mom;
  if (!degenerated) {
    if (verboseLevel > 2)
      G4cout << " rotating to align with reference z axis " << G4endl;

    G4ThreeVector vscm = velocity - valong*scm_direction;
    G4ThreeVector vxcm = scm_direction.cross(velocity);

    if (vscm.mag() > small && vxcm.mag() > small) { // Double check
      if (verboseLevel > 3) {
    G4cout << " reference z axis " << scm_direction
           << " vscm " << vscm << " vxcm " << vxcm << G4endl;
      }
      
      mom_rot.setVect(mom.x()*vscm.unit() + mom.y()*vxcm.unit() +
              mom.z()*scm_direction);
    } else {
      if (verboseLevel) 
    G4cerr << ">>> G4LorentzVector::rotate zero with !degenerated" << G4endl;
    }
  }

  if (verboseLevel > 3) {
    G4cout << " after rotation: px " << mom_rot.x() << " py " << mom_rot.y()
       << " pz " << mom_rot.z() << G4endl;
  }

  return mom_rot;
}

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G4LorentzVector G4LorentzConvertor::rotate	(	const G4LorentzVector &	mom1,
		const G4LorentzVector &	mom
	)		const

Definition at line 215 of file G4LorentzConvertor.cc.

                                                         {
  if (verboseLevel > 2)
    G4cout << " >>> G4LorentzConvertor::rotate(G4LorentzVector,G4LorentzVector)"
       << G4endl;

  if (verboseLevel > 3) {
    G4cout << " before rotation: px " << mom.x() << " py " << mom.y()
       << " pz " << mom.z() << G4endl;
  }

  G4ThreeVector mom1_dir = mom1.vect().unit();
  G4double pv = velocity.dot(mom1_dir);

  G4double vperp = v2 - pv*pv;      // velocity perpendicular to mom1
  if (verboseLevel > 3) {
    G4cout << " vperp " << vperp << " small? " << (vperp <= small) << G4endl;
  }

  G4LorentzVector mom_rot = mom;

  if (vperp > small) {
    if (verboseLevel > 2)
      G4cout << " rotating to align with first z axis " << G4endl;

    G4ThreeVector vmom1 = velocity - pv*mom1_dir;
    G4ThreeVector vxm1  = mom1_dir.cross(velocity);

    if (vmom1.mag() > small && vxm1.mag() > small) {    // Double check
      if (verboseLevel > 3) {
    G4cout << " first z axis " << mom1_dir << G4endl
           << " vmom1 " << vmom1 << " vxm1 " << vxm1 << G4endl;
      }
      
      mom_rot.setVect(mom.x()*vmom1.unit() + mom.y()*vxm1.unit() +
              mom.z()*mom1_dir );
    } else {
      if (verboseLevel) 
    G4cerr << ">>> G4LorentzVector::rotate zero with !degenerated" << G4endl;
    }
  }

  if (verboseLevel > 3) {
    G4cout << " after rotation: px " << mom_rot.x() << " py " << mom_rot.y()
       << " pz " << mom_rot.z() << G4endl;
  }

  return mom_rot;
}

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void G4LorentzConvertor::setBullet

(

const G4InuclParticle *

bullet

)

Definition at line 67 of file G4LorentzConvertor.cc.

                                                                {
  setBullet(bullet->getMomentum());
}

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void G4LorentzConvertor::setBullet ( const G4InuclParticle &  bullet )

inline

Definition at line 60 of file G4LorentzConvertor.hh.

{ setBullet(&bullet); }

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void G4LorentzConvertor::setBullet ( const G4LorentzVector &  bmom )

inline

Definition at line 64 of file G4LorentzConvertor.hh.

                                              {
    bullet_mom = bmom;
    if (verboseLevel > 3) printBullet();
  }

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void G4LorentzConvertor::setBullet ( const G4LorentzVector &  bmom, G4double  bmass  )

inline

Definition at line 75 of file G4LorentzConvertor.hh.

                                                              {
    bullet_mom.setVectM(bmom.vect(), bmass);
    if (verboseLevel > 3) printBullet();
  }

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void G4LorentzConvertor::setTarget

(

const G4InuclParticle *

target

)

Definition at line 71 of file G4LorentzConvertor.cc.

                                                                {
  setTarget(target->getMomentum());
}

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void G4LorentzConvertor::setTarget ( const G4InuclParticle &  target )

inline

Definition at line 61 of file G4LorentzConvertor.hh.

{ setTarget(&target); }

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void G4LorentzConvertor::setTarget ( const G4LorentzVector &  bmom )

inline

Definition at line 69 of file G4LorentzConvertor.hh.

                                              {
    target_mom = bmom;
    if (verboseLevel > 3) printTarget();
  }

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void G4LorentzConvertor::setTarget ( const G4LorentzVector &  tmom, G4double  tmass  )

inline

Definition at line 80 of file G4LorentzConvertor.hh.

                                                              {
    target_mom.setVectM(tmom.vect(), tmass);
    if (verboseLevel > 3) printTarget();
  }

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void G4LorentzConvertor::setVerbose ( G4int  vb = 0 )

inline

Definition at line 55 of file G4LorentzConvertor.hh.

{ verboseLevel = vb; }

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void G4LorentzConvertor::toTheCenterOfMass

(

)

Definition at line 78 of file G4LorentzConvertor.cc.

                                           {
  if (verboseLevel > 2)
    G4cout << " >>> G4LorentzConvertor::toTheCenterOfMass" << G4endl;

  velocity = (target_mom+bullet_mom).boostVector();
  if (verboseLevel > 3) G4cout << " boost " << velocity << G4endl;

  // "SCM" is reverse target momentum in the CM frame
  scm_momentum = target_mom;
  scm_momentum.boost(-velocity);
  scm_momentum.setVect(-scm_momentum.vect());

  if (verboseLevel > 3) G4cout << " pscm " << scm_momentum.vect() << G4endl;

  fillKinematics();
}

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void G4LorentzConvertor::toTheTargetRestFrame

(

)

Definition at line 95 of file G4LorentzConvertor.cc.

                                              {
  if (verboseLevel > 2)
    G4cout << " >>> G4LorentzConvertor::toTheTargetRestFrame" << G4endl;

  velocity = target_mom.boostVector();
  if (verboseLevel > 3) G4cout << " boost " << velocity << G4endl;

  // "SCM" is bullet momentum in the target's frame
  scm_momentum = bullet_mom;
  scm_momentum.boost(-velocity);

  if (verboseLevel > 3) G4cout << " pseudo-pscm " << scm_momentum.vect() << G4endl;

  fillKinematics();
}

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G4bool G4LorentzConvertor::trivial ( ) const

inline

Definition at line 108 of file G4LorentzConvertor.hh.

{ return degenerated; }

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---

The documentation for this class was generated from the following files:

• geant4.10.03.p01/source/processes/hadronic/models/cascade/cascade/include/G4LorentzConvertor.hh
• geant4.10.03.p01/source/processes/hadronic/models/cascade/cascade/src/G4LorentzConvertor.cc