FacetFitter Class Reference

Utility class to fit hit triplet and relations of them. More...

#include <FacetFitter.h>

Static Public Member Functions
static double	fit (const TrackingUtilities::CDCFacet &facet, int nSteps=100)
	Fits a proper line to facet and returns the chi2.
static TrackingUtilities::UncertainParameterLine2D	fit (const TrackingUtilities::CDCFacet &fromFacet, const TrackingUtilities::CDCFacet &toFacet, int nSteps=100)
	Fit a line the positions xyl and the weights.
static TrackingUtilities::UncertainParameterLine2D	fit (TrackingUtilities::Matrix< double, 3, 3 > xyl, TrackingUtilities::Matrix< double, 3, 1 > w, int nSteps=100)
	Fit a line the positions xyl and the weights.

Detailed Description

Utility class to fit hit triplet and relations of them.

Definition at line 24 of file FacetFitter.h.

Member Function Documentation

fit() [1/3]

double fit ( const TrackingUtilities::CDCFacet & facet, int nSteps = 100 )

static

Fits a proper line to facet and returns the chi2.

Definition at line 167 of file FacetFitter.cc.

{
  // Measurement matrix
  Matrix<double, 3, 3> xyl = Matrix<double, 3, 3>::Zero();
 
  // Weight matrix
  Matrix<double, 3, 1> w = Matrix<double, 3, 1>::Zero();
 
  const CDCRLWireHit& startRLWireHit = facet.getStartRLWireHit();
  const CDCRLWireHit& middleRLWireHit = facet.getMiddleRLWireHit();
  const CDCRLWireHit& endRLWireHit = facet.getEndRLWireHit();
 
  const Vector2D support = middleRLWireHit.getWireHit().getRefPos2D();
 
  const double startDriftLengthVar = startRLWireHit.getRefDriftLengthVariance();
  const Vector2D startWirePos2D = startRLWireHit.getWireHit().getRefPos2D();
  xyl(0, 0) = startWirePos2D.x() - support.x();
  xyl(0, 1) = startWirePos2D.y() - support.y();
  xyl(0, 2) = startRLWireHit.getSignedRefDriftLength();
  w(0) = 1.0 / startDriftLengthVar;
 
  const double middleDriftLengthVar = middleRLWireHit.getRefDriftLengthVariance();
  const Vector2D middleWirePos2D = middleRLWireHit.getWireHit().getRefPos2D();
  xyl(1, 0) = middleWirePos2D.x() - support.x();
  xyl(1, 1) = middleWirePos2D.y() - support.y();
  xyl(1, 2) = middleRLWireHit.getSignedRefDriftLength();
  w(1) = 1.0 / middleDriftLengthVar;
 
  const double endDriftLengthVar = endRLWireHit.getRefDriftLengthVariance();
  const Vector2D endWirePos2D = endRLWireHit.getWireHit().getRefPos2D();
  xyl(2, 0) = endWirePos2D.x() - support.x();
  xyl(2, 1) = endWirePos2D.y() - support.y();
  xyl(2, 2) = endRLWireHit.getSignedRefDriftLength();
  w(2) = 1.0 / endDriftLengthVar;
 
  UncertainParameterLine2D fitLine{ ::fit(std::move(xyl), std::move(w), nSteps) };
  fitLine.passiveMoveBy(-support);
  facet.setFitLine(fitLine);
  return fitLine.chi2();
}

fit() [2/3]

UncertainParameterLine2D fit ( const TrackingUtilities::CDCFacet & fromFacet, const TrackingUtilities::CDCFacet & toFacet, int nSteps = 100 )

static

Fit a line the positions xyl and the weights.

Parameters

fromFacet	First facet from the pair of facets
toFacet	Second facet from the pair of facets
nSteps	Maximal number of steps to be taken in the mimisation

Definition at line 209 of file FacetFitter.cc.

{
  // Observations matrix
  Matrix<double, 6, 3> xyl = Matrix<double, 6, 3>::Zero();
 
  // Weight matrix
  Matrix<double, 6, 1> w = Matrix<double, 6, 1>::Zero();
 
  const Vector2D support = Vector2D::average(fromFacet.getMiddleWireHit().getRefPos2D(),
                                             toFacet.getMiddleWireHit().getRefPos2D());
  {
    const CDCRLWireHit& startRLWireHit = fromFacet.getStartRLWireHit();
    const CDCRLWireHit& middleRLWireHit = fromFacet.getMiddleRLWireHit();
    const CDCRLWireHit& endRLWireHit = fromFacet.getEndRLWireHit();
 
    const double startDriftLengthVar = startRLWireHit.getRefDriftLengthVariance();
    const Vector2D startWirePos2D = startRLWireHit.getWireHit().getRefPos2D();
    xyl(0, 0) = startWirePos2D.x() - support.x();
    xyl(0, 1) = startWirePos2D.y() - support.y();
    xyl(0, 2) = startRLWireHit.getSignedRefDriftLength();
    w(0) = 1.0 / startDriftLengthVar;
 
    const double middleDriftLengthVar = middleRLWireHit.getRefDriftLengthVariance();
    const Vector2D middleWirePos2D = middleRLWireHit.getWireHit().getRefPos2D();
    xyl(1, 0) = middleWirePos2D.x() - support.x();
    xyl(1, 1) = middleWirePos2D.y() - support.y();
    xyl(1, 2) = middleRLWireHit.getSignedRefDriftLength();
    w(1) = 1.0 / middleDriftLengthVar;
 
    const double endDriftLengthVar = endRLWireHit.getRefDriftLengthVariance();
    const Vector2D endWirePos2D = endRLWireHit.getWireHit().getRefPos2D();
    xyl(2, 0) = endWirePos2D.x() - support.x();
    xyl(2, 1) = endWirePos2D.y() - support.y();
    xyl(2, 2) = endRLWireHit.getSignedRefDriftLength();
    w(2) = 1.0 / endDriftLengthVar;
  }
 
  {
    const CDCRLWireHit& startRLWireHit = toFacet.getStartRLWireHit();
    const CDCRLWireHit& middleRLWireHit = toFacet.getMiddleRLWireHit();
    const CDCRLWireHit& endRLWireHit = toFacet.getEndRLWireHit();
 
    const double startDriftLengthVar = startRLWireHit.getRefDriftLengthVariance();
    const Vector2D startWirePos2D = startRLWireHit.getWireHit().getRefPos2D();
    xyl(3, 0) = startWirePos2D.x() - support.x();
    xyl(3, 1) = startWirePos2D.y() - support.y();
    xyl(3, 2) = startRLWireHit.getSignedRefDriftLength();
    w(3) = 1.0 / startDriftLengthVar;
 
    const double middleDriftLengthVar = middleRLWireHit.getRefDriftLengthVariance();
    const Vector2D middleWirePos2D = middleRLWireHit.getWireHit().getRefPos2D();
    xyl(4, 0) = middleWirePos2D.x() - support.x();
    xyl(4, 1) = middleWirePos2D.y() - support.y();
    xyl(4, 2) = middleRLWireHit.getSignedRefDriftLength();
    w(4) = 1.0 / middleDriftLengthVar;
 
    const double endDriftLengthVar = endRLWireHit.getRefDriftLengthVariance();
    const Vector2D endWirePos2D = endRLWireHit.getWireHit().getRefPos2D();
    xyl(5, 0) = endWirePos2D.x() - support.x();
    xyl(5, 1) = endWirePos2D.y() - support.y();
    xyl(5, 2) = endRLWireHit.getSignedRefDriftLength();
    w(5) = 1.0 / endDriftLengthVar;
  }
 
  UncertainParameterLine2D fitLine{ ::fit(std::move(xyl), std::move(w), nSteps) };
  fitLine.passiveMoveBy(-support);
  return fitLine;
}

fit() [3/3]

static TrackingUtilities::UncertainParameterLine2D fit ( TrackingUtilities::Matrix< double, 3, 3 > xyl, TrackingUtilities::Matrix< double, 3, 1 > w, int nSteps = 100 )

static

Fit a line the positions xyl and the weights.

Fits a line to a number of observations with tunable acurracy versus execution speed. Special implementations for nSteps = 0 and nSteps=1 have been integrated. High nSteps use a general minimization method.

Parameters

xyl	A matrix of drift length observations
w	An array of weights corresponding to the observations
nSteps	Maximal number of steps to be taken in the mimisation

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

• tracking/trackFindingCDC/fitting/include/FacetFitter.h
• tracking/trackFindingCDC/fitting/src/FacetFitter.cc