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.

00035   : EndpointA(PntA), 
00036     VecAtoB(PntB-PntA)
00037 { 
00038   fABdistanceSq = VecAtoB.mag2() ;  
00039   /*
00040   G4double distABsquared = VecAtoB.mag2() ;  
00041   if ( distABsquared == 0.0)
00042   {
00043     G4Exception("G4LineSection::G4LineSection()", "GeomField0002",
00044                 FatalException, "Equal points in input (line->point) ?") ;
00045   }
00046   else
00047   {
00048     inverse_square_distAB=1.0 / distABsquared ;
00049   }
00050   */
00051 }


Member Function Documentation

G4double G4LineSection::Dist ( G4ThreeVector  OtherPnt  )  const

Definition at line 53 of file G4LineSection.cc.

Referenced by Distline().

00054 {
00055   G4double       dist_sq;  
00056   G4ThreeVector  VecAZ;
00057   G4double sq_VecAZ, inner_prod, unit_projection ; 
00058 
00059   VecAZ= OtherPnt - EndpointA;
00060   sq_VecAZ = VecAZ.mag2();
00061 
00062   inner_prod= VecAtoB.dot( VecAZ );
00063    
00064   //  Determine  Projection(AZ on AB) / Length(AB) 
00065   //
00066   if( fABdistanceSq != 0.0 )
00067   {
00068     //  unit_projection= inner_prod * InvsqDistAB();
00069     unit_projection = inner_prod/fABdistanceSq;
00070 
00071     if( (0. <= unit_projection ) && (unit_projection <= 1.0 ) )
00072     {
00073       dist_sq= sq_VecAZ -  unit_projection * inner_prod ;
00074     }
00075     else
00076     {
00077      //  The perpendicular from the point to the line AB meets the line
00078      //   in a point outside the line segment!
00079      
00080       if( unit_projection < 0. ) // A is the closest point
00081       {
00082         dist_sq= sq_VecAZ;  
00083       }
00084       else                       // B is the closest point
00085       {
00086         G4ThreeVector   EndpointB = EndpointA + VecAtoB;
00087         G4ThreeVector   VecBZ =     OtherPnt - EndpointB;
00088         dist_sq =  VecBZ.mag2();
00089       }
00090     }
00091   }
00092   else
00093   {
00094      dist_sq = (OtherPnt - EndpointA).mag2() ;   
00095   }  
00096   if( dist_sq < 0.0 ) dist_sq = 0.0 ;
00097 
00098   return std::sqrt(dist_sq) ;  
00099 }

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

00104 {
00105   G4LineSection LineAB( LinePntA, LinePntB );  // Line from A to B
00106 
00107   return LineAB.Dist( OtherPnt );
00108 }

G4double G4LineSection::GetABdistanceSq (  )  const [inline]

Definition at line 55 of file G4LineSection.hh.

00055 { return fABdistanceSq ; }


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