G4LineSection Class Reference

#include <G4LineSection.hh>

Public Member Functions
	G4LineSection (const G4ThreeVector &PntA, const G4ThreeVector &PntB)
G4double	Dist (G4ThreeVector OtherPnt) const
G4double	GetABdistanceSq () const

Static Public Member Functions
static G4double	Distline (const G4ThreeVector &OtherPnt, const G4ThreeVector &LinePntA, const G4ThreeVector &LinePntB)

Detailed Description

Definition at line 47 of file G4LineSection.hh.

Constructor & Destructor Documentation

G4LineSection::G4LineSection	(	const G4ThreeVector &	PntA,
		const G4ThreeVector &	PntB
	)

Definition at line 33 of file G4LineSection.cc.

References CLHEP::Hep3Vector::mag2().

  : EndpointA(PntA), 
    VecAtoB(PntB-PntA)
{ 
  fABdistanceSq = VecAtoB.mag2() ;  
  /*
  G4double distABsquared = VecAtoB.mag2() ;  
  if ( distABsquared == 0.0)
  {
    G4Exception("G4LineSection::G4LineSection()", "GeomField0002",
                FatalException, "Equal points in input (line->point) ?") ;
  }
  else
  {
    inverse_square_distAB=1.0 / distABsquared ;
  }
  */
}

Member Function Documentation

G4double G4LineSection::Dist

(

G4ThreeVector

OtherPnt

)

const

Definition at line 53 of file G4LineSection.cc.

References CLHEP::Hep3Vector::dot(), and CLHEP::Hep3Vector::mag2().

Referenced by Distline().

{
  G4double       dist_sq;  
  G4ThreeVector  VecAZ;
  G4double sq_VecAZ, inner_prod, unit_projection ; 

  VecAZ= OtherPnt - EndpointA;
  sq_VecAZ = VecAZ.mag2();

  inner_prod= VecAtoB.dot( VecAZ );
   
  //  Determine  Projection(AZ on AB) / Length(AB) 
  //
  if( fABdistanceSq != 0.0 )
  {
    //  unit_projection= inner_prod * InvsqDistAB();
    unit_projection = inner_prod/fABdistanceSq;

    if( (0. <= unit_projection ) && (unit_projection <= 1.0 ) )
    {
      dist_sq= sq_VecAZ -  unit_projection * inner_prod ;
    }
    else
    {
     //  The perpendicular from the point to the line AB meets the line
     //   in a point outside the line segment!
     
      if( unit_projection < 0. ) // A is the closest point
      {
        dist_sq= sq_VecAZ;  
      }
      else                       // B is the closest point
      {
    G4ThreeVector   EndpointB = EndpointA + VecAtoB;
        G4ThreeVector   VecBZ =     OtherPnt - EndpointB;
        dist_sq =  VecBZ.mag2();
      }
    }
  }
  else
  {
     dist_sq = (OtherPnt - EndpointA).mag2() ;   
  }  
  if( dist_sq < 0.0 ) dist_sq = 0.0 ;

  return std::sqrt(dist_sq) ;  
}

G4double G4LineSection::Distline ( const G4ThreeVector &  OtherPnt, const G4ThreeVector &  LinePntA, const G4ThreeVector &  LinePntB  )

static

Definition at line 101 of file G4LineSection.cc.

References Dist().

Referenced by G4ConstRK4::DistChord(), G4RKG3_Stepper::DistChord(), G4CashKarpRKF45::DistChord(), and G4MagErrorStepper::DistChord().

{
  G4LineSection LineAB( LinePntA, LinePntB );  // Line from A to B

  return LineAB.Dist( OtherPnt );
}

G4double G4LineSection::GetABdistanceSq ( ) const

inline

Definition at line 55 of file G4LineSection.hh.

{ return fABdistanceSq ; }

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

• G4LineSection.hh
• G4LineSection.cc