GFSpacepointHitPolicy Class Reference

Policy class implementing a space point hit geometry. More...

#include <GFSpacepointHitPolicy.h>

Inheritance diagram for GFSpacepointHitPolicy:

Public Member Functions
	GFSpacepointHitPolicy ()
const GFDetPlane &	detPlane (GFAbsRecoHit *, GFAbsTrackRep *)
	Get detector plane perpendicular to track. More...
TMatrixT< double >	hitCoord (GFAbsRecoHit *, const GFDetPlane &)
	Hit coordinates in detector plane. More...
TMatrixT< double >	hitCov (GFAbsRecoHit *, const GFDetPlane &)
	Hit covariances in detector plane. More...
virtual	~GFSpacepointHitPolicy ()
const std::string &	getName ()
	ClassDef (GFSpacepointHitPolicy, 1)

Private Attributes
GFDetPlane	fPlane

Static Private Attributes
static const std::string	fPolicyName = "GFSpacepointHitPolicy"

Detailed Description

Policy class implementing a space point hit geometry.

Author

Christian Höppner (Technische Universität München, original author)

Sebastian Neubert (Technische Universität München, original author)

RecoHits for detectors measuring 3D space points should inherit from RecoHitIfc<GFSpacepointHitPolicy>.

For a space point the detector plane has to be defined with respect to a track representation. GFSpacepointHitPolicy implements a scheme where the detectorplane is chosen perpendicular to the track. In a track fit only 2 of the three coordinates of a space point are independent (the track is a one-dimensional object). Therefore the 3D data of the hit is used to define a proper detector plane into which the hit coordinates are then projected.

Definition at line 52 of file GFSpacepointHitPolicy.h.

Constructor & Destructor Documentation

GFSpacepointHitPolicy::GFSpacepointHitPolicy ( )

inline

Definition at line 56 of file GFSpacepointHitPolicy.h.

{;}

virtual GFSpacepointHitPolicy::~GFSpacepointHitPolicy ( )

inlinevirtual

Definition at line 75 of file GFSpacepointHitPolicy.h.

{;}

Member Function Documentation

GFSpacepointHitPolicy::ClassDef	(	GFSpacepointHitPolicy	,
		1
	)

const GFDetPlane & GFSpacepointHitPolicy::detPlane	(	GFAbsRecoHit *	hit,
		GFAbsTrackRep *	rep
	)

Get detector plane perpendicular to track.

The detector plane is contructed from the position of the hit and the track representation. For this the track is extrapolated to the point of closest approach to the hit.

Definition at line 89 of file GFSpacepointHitPolicy.cxx.

References GFAbsTrackRep::extrapolateToPoint(), fPlane, GFAbsRecoHit::getRawHitCoord(), point, GFDetPlane::setNormal(), and GFDetPlane::setO().

{
  TMatrixT<double> rawcoord = hit->getRawHitCoord();
  TVector3 point(rawcoord[0][0],rawcoord[1][0],rawcoord[2][0]);

  TVector3 poca,dirInPoca;
  rep->extrapolateToPoint(point,poca,dirInPoca);

  fPlane.setO(point);
  fPlane.setNormal(dirInPoca);

  return fPlane;
}

const std::string& GFSpacepointHitPolicy::getName ( )

inline

Definition at line 77 of file GFSpacepointHitPolicy.h.

References fPolicyName.

{return fPolicyName;}

TMatrixT< double > GFSpacepointHitPolicy::hitCoord	(	GFAbsRecoHit *	hit,
		const GFDetPlane &	plane
	)

Hit coordinates in detector plane.

Definition at line 30 of file GFSpacepointHitPolicy.cxx.

References GFDetPlane::getO(), GFAbsRecoHit::getRawHitCoord(), GFDetPlane::getU(), and GFDetPlane::getV().

{
  TMatrixT<double> returnMat(2,1);

  TMatrixT<double> _D(3,1);
  TVector3 _U;
  TVector3 _V;

  _D[0][0] = (plane.getO())[0];
  _D[1][0] = (plane.getO())[1];
  _D[2][0] = (plane.getO())[2];

  _D *= -1.; 
  _D += hit->getRawHitCoord();
  //now the vector _D points from the origin of the plane to the hit point


  _U = plane.getU();
  _V = plane.getV();


  returnMat[0][0] = _D[0][0] * _U[0] + _D[1][0] * _U[1] + _D[2][0] * _U[2];
  returnMat[1][0] = _D[0][0] * _V[0] + _D[1][0] * _V[1] + _D[2][0] * _V[2];
  //std::cout << "hitCoord="<<std::endl;
  //returnMat.Print();
  return returnMat;
}

TMatrixT< double > GFSpacepointHitPolicy::hitCov	(	GFAbsRecoHit *	hit,
		const GFDetPlane &	plane
	)

Hit covariances in detector plane.

Definition at line 59 of file GFSpacepointHitPolicy.cxx.

References GFAbsRecoHit::getRawHitCov(), GFDetPlane::getU(), and GFDetPlane::getV().

{
  TVector3 _U;
  TVector3 _V;

  _U = plane.getU();
  _V = plane.getV();

  TMatrixT<double> rawCov = hit->getRawHitCov();

  TMatrixT<double> jac(3,2);
  
  // jac = dF_i/dx_j = s_unitvec * t_untivec, with s=u,v and t=x,y,z
  jac[0][0] = _U[0];
  jac[1][0] = _U[1];
  jac[2][0] = _U[2];
  jac[0][1] = _V[0];
  jac[1][1] = _V[1];
  jac[2][1] = _V[2];

  TMatrixT<double> jac_orig = jac;
  TMatrixT<double> jac_t = jac.T();

  TMatrixT<double> result=jac_t * (rawCov * jac_orig);
  //std::cout << "hitCov="<<std::endl;
  //result.Print();
  return  result;
}

Member Data Documentation

GFDetPlane GFSpacepointHitPolicy::fPlane

private

Definition at line 82 of file GFSpacepointHitPolicy.h.

Referenced by detPlane().

const std::string GFSpacepointHitPolicy::fPolicyName = "GFSpacepointHitPolicy"

staticprivate

Definition at line 79 of file GFSpacepointHitPolicy.h.

Referenced by getName().

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

• GFSpacepointHitPolicy.h
• GFSpacepointHitPolicy.cxx