#include <GetLineCovMatrix.h>

Public Member Functions
	GetLineCovMatrix (GlobalPoint, GlobalPoint, GlobalError, GlobalError)
GlobalError	GetMatrix (GlobalPoint)
	~GetLineCovMatrix ()
Private Attributes
CLHEP::HepMatrix	B
CLHEP::HepMatrix	CombinedErrorMatrix
GlobalPoint	PointOne
GlobalPoint	PointTwo

Detailed Description

Definition at line 12 of file GetLineCovMatrix.h.

Constructor & Destructor Documentation

GetLineCovMatrix::GetLineCovMatrix	(	GlobalPoint	pointOne,
		GlobalPoint	pointTwo,
		GlobalError	ErrorOne,
		GlobalError	ErrorTwo
	)

Definition at line 4 of file GetLineCovMatrix.cc.

References CombinedErrorMatrix, GlobalErrorBase< T, ErrorWeightType >::cxx(), GlobalErrorBase< T, ErrorWeightType >::cyx(), GlobalErrorBase< T, ErrorWeightType >::cyy(), GlobalErrorBase< T, ErrorWeightType >::czx(), GlobalErrorBase< T, ErrorWeightType >::czy(), GlobalErrorBase< T, ErrorWeightType >::czz(), PointOne, and PointTwo.

{

  PointOne = pointOne;
  PointTwo = pointTwo;

  CombinedErrorMatrix = CLHEP::HepMatrix(6, 6, 0);
 
  CombinedErrorMatrix[0][0] = ErrorOne.cxx();
  CombinedErrorMatrix[1][0] = ErrorOne.cyx(); 
  CombinedErrorMatrix[0][1] = ErrorOne.cyx();
  CombinedErrorMatrix[1][1] = ErrorOne.cyy();
  CombinedErrorMatrix[2][0] = ErrorOne.czx();
  CombinedErrorMatrix[0][2] = ErrorOne.czx(); 
  CombinedErrorMatrix[2][1] = ErrorOne.czy();
  CombinedErrorMatrix[1][2] = ErrorOne.czy(); 
  CombinedErrorMatrix[2][2] = ErrorOne.czz();
    
  CombinedErrorMatrix[3][3] = ErrorTwo.cxx();
  CombinedErrorMatrix[4][3] = ErrorTwo.cyx(); 
  CombinedErrorMatrix[3][4] = ErrorTwo.cyx();
  CombinedErrorMatrix[4][4] = ErrorTwo.cyy();
  CombinedErrorMatrix[5][3] = ErrorTwo.czx();
  CombinedErrorMatrix[3][5] = ErrorTwo.czx(); 
  CombinedErrorMatrix[5][4] = ErrorTwo.czy();
  CombinedErrorMatrix[4][5] = ErrorTwo.czy(); 
  CombinedErrorMatrix[5][5] = ErrorTwo.czz();

  B = CLHEP::HepMatrix(3, 6, 0);  
}

GetLineCovMatrix::~GetLineCovMatrix ( ) [inline]

Definition at line 18 of file GetLineCovMatrix.h.

{}

Member Function Documentation

GlobalError GetLineCovMatrix::GetMatrix ( GlobalPoint PointThree )

Definition at line 36 of file GetLineCovMatrix.cc.

References CombinedErrorMatrix, PointOne, PointTwo, asciidump::s, PV3DBase< T, PVType, FrameType >::x(), PV3DBase< T, PVType, FrameType >::y(), and PV3DBase< T, PVType, FrameType >::z().

{ 
  // the linear equation is  K = PointOne + (PointTwo-PointOne)*s
  double s;  
  if( !fabs(PointTwo.x() - PointOne.x()) < 0.00000001 ) 
    s =  (PointThree.x() - PointOne.x()) / (PointTwo.x() -  PointOne.x()) ; 
  else {
    if( !fabs(PointTwo.y() - PointOne.y()) < 0.00000001 ) 
      s =  (PointThree.y() - PointOne.y()) / (PointTwo.y() -  PointOne.y()) ;   
    else { 
      if( !fabs(PointTwo.z() - PointOne.z()) < 0.00000001 ) 
        s =  (PointThree.z() - PointOne.z()) / (PointTwo.z() -  PointOne.z()) ;
      else {
        GlobalError EmptyError(0, 0, 0, 0, 0, 0);
        return EmptyError;
      }
    }
  }

  B[0][0] = 1-s;    
  B[0][3] = s;
  B[1][1] = 1-s;   
  B[1][4] = s;
  B[2][2] = 1-s;  
  B[2][5] = s;

  CLHEP::HepMatrix Result = B * CombinedErrorMatrix * B.T();
  
  GlobalError TheGlobalError( Result[0][0],  Result[1][0],  Result[1][1], Result[2][0],  Result[2][1],  Result[2][2] );
  return TheGlobalError;
}