A container to store material properties for each material surface. More...

#include <Chi2Fitter.h>

Collaboration diagram for MuonExperimental::Gx2fMaterialProperties:

Classes
struct	ELossAtSurface
	Auxiliary struct to include the measured energy loss at a surface. More...
struct	ScatteringAtSurface
	Auxiliary struct to describe the material scattering at a surface. More...

Public Member Functions
	Gx2fMaterialProperties (ScatteringAtSurface &&scatterer, ELossAtSurface &&eLoss)
	Constructor to initialize material properties.
constexpr bool	materialIsValid () const
	Accessor for the material validity flag.
constexpr std::size_t	nDim () const
	Number of dimensions from the material scatterer.
const ScatteringAtSurface &	scatterer () const
const ELossAtSurface &	energyLoss () const
constexpr double	deltaTheta () const
constexpr double	deltaPhi () const
constexpr double	lostEnergy () const
constexpr double	qOverPderiv () const
constexpr double	qOverPratio () const
void	updateTrackParameters (BoundTrackParameters &trackPars)
	Update the track parameters with the scattering angles and.
void	contributionToGx2fSums (Gx2fSystem &extendedSystem, const double theta, const std::size_t firstParamIdx, const Logger &logger) const
void	updateParameters (const Eigen::VectorXd &deltaParamsExtended, const std::size_t firstParamIdx)

Private Attributes
ScatteringAtSurface	m_scatterer {}
	Description of the scattering angles.
ELossAtSurface	m_eloss {}
	Description of the energy loss.
double	m_lostEnergy {0.}
	Fitted parameters.
double	m_scatTheta {0.}
	Fitted delta theta scattering.
double	m_scatPhi {0.}
	Fitted delta phi scattering.
double	m_qOverPderiv {0.}
	qOverP derivative with respect to eloss
double	m_qOverPratio {1.}

Detailed Description

A container to store material properties for each material surface.

This struct holds the scattering angles, the inverse covariance of the material, and a validity flag indicating whether the material is valid for the scattering process.

Definition at line 62 of file Chi2Fitter.h.

Constructor & Destructor Documentation

◆ Gx2fMaterialProperties()

MuonExperimental::Gx2fMaterialProperties::Gx2fMaterialProperties	(	ScatteringAtSurface &&	scatterer,
		ELossAtSurface &&	eLoss )

inlineexplicit

Constructor to initialize material properties.

Parameters

scatteringAngles_	The vector of scattering angles.
invCovarianceMaterial_	The inverse covariance of the material.
materialIsValid_	A boolean flag indicating whether the material is valid.

Definition at line 158 of file Chi2Fitter.h.

      : m_scatterer{std::move(scatterer)},
        m_eloss{std::move(eLoss)},
        m_lostEnergy{m_eloss.isValid() ? m_eloss.lostEnergy() : 0.} {}

Member Function Documentation

◆ contributionToGx2fSums()

void MuonExperimental::Gx2fMaterialProperties::contributionToGx2fSums	(	Gx2fSystem &	extendedSystem,
		const double	theta,
		const std::size_t	firstParamIdx,
		const Logger &	logger ) const

Definition at line 93 of file Chi2Fitter.cxx.

                                {
  if (m_scatterer.isValid()) {
    const double invCovTheta = Acts::square(1. / m_scatterer.sigma());
    const double sinThetaLoc = std::sin(theta);
    const double invCovPhi = invCovTheta * Acts::square(sinThetaLoc);
 
    // Phi contribution
    extendedSystem.aMatrix()(stateIdx, stateIdx) += invCovPhi;
    extendedSystem.bVector()(stateIdx, 0) -= invCovPhi * deltaPhi();
    extendedSystem.chi2() += invCovPhi * Acts::square(deltaPhi());
 
    // Theta Contribution
    extendedSystem.aMatrix()(stateIdx + 1, stateIdx + 1) += invCovTheta;
    extendedSystem.bVector()(stateIdx + 1, 0) -= invCovTheta * deltaTheta();
    extendedSystem.chi2() += invCovTheta * Acts::square(deltaTheta());
    ACTS_VERBOSE("Scattering contributions in contributionToGx2fSums:\n"
                 << "     index: " << stateIdx << "-" << (stateIdx + 1) << " \n"
                 << "    invCov:        " << invCovPhi << "\n"
                 << "    sinThetaLoc:   " << sinThetaLoc << "\n"
                 << "    Phi:\n"
                 << "        scattering angle:     " << deltaPhi() << "\n"
                 << "        aMatrix contribution: " << invCovPhi << "\n"
                 << "        bVector contribution: " << invCovPhi * deltaPhi()
                 << "\n"
                 << "        chi2sum contribution: "
                 << invCovPhi * Acts::square(deltaPhi()) << "\n"
                 << "    Theta:\n"
                 << "        scattering angle:     " << deltaTheta() << "\n"
                 << "        aMatrix contribution: " << invCovTheta << "\n"
                 << "        bVector contribution: "
                 << invCovTheta * deltaTheta() << "\n"
                 << "        chi2sum contribution: "
                 << invCovTheta * Acts::square(deltaTheta()));
  }
 
  if (m_eloss.isValid()) {
    const std::size_t eLossIdx = stateIdx + (nDim() - 1ul);
    extendedSystem.aMatrix()(eLossIdx, eLossIdx) +=
        Acts::square(1. / m_eloss.lostSigma());
    extendedSystem.bVector()(eLossIdx, 0) -=
        Acts::square(1. / m_eloss.lostSigma()) *
        (m_lostEnergy - m_eloss.lostEnergy());
    extendedSystem.chi2() += Acts::square(
        (m_lostEnergy - m_eloss.lostEnergy()) / m_eloss.lostSigma());
    // The energy loss constraint to require only positive energy loss for the
    // free parameter
    constexpr double Nepsilon = Acts::square(1. / 10._keV);
    if (m_lostEnergy < 10._keV) {
      ACTS_VERBOSE(
          "Add penalty term to the chi2 to push the energy loss above zero");
      extendedSystem.chi2() += Nepsilon * Acts::square(m_lostEnergy);
      extendedSystem.bVector()(eLossIdx, 0) -= Nepsilon * m_lostEnergy;
      extendedSystem.aMatrix()(eLossIdx, eLossIdx) += Nepsilon;
    }
    ACTS_VERBOSE("Energy loss contributions in contributionToGx2fSums:\n"
                 << "       index: " << eLossIdx << " \n"
                 << "       measured loss: " << m_eloss.lostEnergy() << "+-"
                 << (m_eloss.lostSigma()) << ", \n"
                 << "       currently estimated loss: " << m_lostEnergy << "\n"
                 << "  --> chi2 contribution: "
                 << Acts::square((m_lostEnergy - m_eloss.lostEnergy()) /
                                 m_eloss.lostSigma())
                 << "\n"
                 << "  --> aMatrix contribution: "
                 << Acts::square(1. / m_eloss.lostSigma()) << "\n"
                 << "  --> bVector contribution: "
                 << Acts::square(1. / m_eloss.lostSigma()) *
                        (m_lostEnergy - m_eloss.lostEnergy()));
  }
}

◆ deltaPhi()

double MuonExperimental::Gx2fMaterialProperties::deltaPhi ( ) const

inlineconstexpr

Definition at line 183 of file Chi2Fitter.h.

183{ return m_scatPhi; }

MuonExperimental::Gx2fMaterialProperties::m_scatPhi

double m_scatPhi

Fitted delta phi scattering.

Definition Chi2Fitter.h:219

◆ deltaTheta()

double MuonExperimental::Gx2fMaterialProperties::deltaTheta ( ) const

inlineconstexpr

Definition at line 181 of file Chi2Fitter.h.

181{ return m_scatTheta; }

MuonExperimental::Gx2fMaterialProperties::m_scatTheta

double m_scatTheta

Fitted delta theta scattering.

Definition Chi2Fitter.h:217

◆ energyLoss()

const ELossAtSurface & MuonExperimental::Gx2fMaterialProperties::energyLoss ( ) const

inline

Definition at line 179 of file Chi2Fitter.h.

179{ return m_eloss; }

◆ lostEnergy()

double MuonExperimental::Gx2fMaterialProperties::lostEnergy ( ) const

inlineconstexpr

Definition at line 185 of file Chi2Fitter.h.

185{ return m_lostEnergy; }

◆ materialIsValid()

bool MuonExperimental::Gx2fMaterialProperties::materialIsValid ( ) const

inlineconstexpr

Accessor for the material validity flag.

Returns: True if material is valid for scattering calculations, false for vacuum or zero thickness

Definition at line 166 of file Chi2Fitter.h.

                                         {
    return m_scatterer.isValid() || m_eloss.isValid();
  }

◆ nDim()

std::size_t MuonExperimental::Gx2fMaterialProperties::nDim ( ) const

inlineconstexpr

Number of dimensions from the material scatterer.

Returns: Number of dimensions from the material scatterer to the parameter vector

Definition at line 172 of file Chi2Fitter.h.

                                   {
    return (m_scatterer.isValid() ? 2ul : 0ul) +
           (m_eloss.isValid() ? 1ul : 0ul);
  }

◆ qOverPderiv()

double MuonExperimental::Gx2fMaterialProperties::qOverPderiv ( ) const

inlineconstexpr

Definition at line 187 of file Chi2Fitter.h.

187{ return m_qOverPderiv; }

MuonExperimental::Gx2fMaterialProperties::m_qOverPderiv

double m_qOverPderiv

qOverP derivative with respect to eloss

Definition Chi2Fitter.h:221

◆ qOverPratio()

double MuonExperimental::Gx2fMaterialProperties::qOverPratio ( ) const

inlineconstexpr

Definition at line 189 of file Chi2Fitter.h.

189{ return m_qOverPratio; }

MuonExperimental::Gx2fMaterialProperties::m_qOverPratio

double m_qOverPratio

Definition Chi2Fitter.h:223

◆ scatterer()

const ScatteringAtSurface & MuonExperimental::Gx2fMaterialProperties::scatterer ( ) const

inline

Definition at line 177 of file Chi2Fitter.h.

177{ return m_scatterer; }

◆ updateParameters()

void MuonExperimental::Gx2fMaterialProperties::updateParameters	(	const Eigen::VectorXd &	deltaParamsExtended,
		const std::size_t	firstParamIdx )

Definition at line 39 of file Chi2Fitter.cxx.

                                                                        {
  if (m_scatterer.isValid()) {
    m_scatPhi += deltaParamsExtended[stateIdx];
    m_scatTheta += deltaParamsExtended[stateIdx + 1ul];
  }
  if (m_eloss.isValid()) {
    const std::size_t eLossIdx = stateIdx + (nDim() - 1ul);
    m_lostEnergy += deltaParamsExtended[eLossIdx];
  }
}

◆ updateTrackParameters()

void MuonExperimental::Gx2fMaterialProperties::updateTrackParameters ( BoundTrackParameters & trackPars )

Update the track parameters with the scattering angles and.

Parameters

trackPars The bound track parameters fetched from the stepper which will be fed back to the stepper to adjust the trajectory position

Definition at line 51 of file Chi2Fitter.cxx.

                                     {
  if (m_scatterer.isValid()) {
    trackPars.parameters()[eBoundPhi] += deltaPhi();
    trackPars.parameters()[eBoundTheta] += deltaTheta();
  }
  if (m_eloss.isValid()) {
    const ParticleHypothesis& hypot = trackPars.particleHypothesis();
    const double nextE =
        fastHypot(hypot.mass(), trackPars.absoluteMomentum()) - m_lostEnergy;
    const double qOverPBefore = trackPars.parameters()[eBoundQOverP];
    const double pAfter =
        (hypot.mass() < nextE) ? fastCathetus(nextE, hypot.mass()) : 0;
 
    if (pAfter <= Acts::s_epsilon) {
      // Fitted loss exceeds the available momentum: leave the parameters
      // untouched, and degrade to no contribution rather than a division by
      // zero.
      // ACTS_WARNING("Fitted energy loss exceeds available momentum. "
      //               << "Momentum before: " << trackPars.absoluteMomentum()
      //               << ", fitted loss: " << m_lostEnergy
      //               << ", fitted momentum after: " << pAfter);
      m_qOverPderiv = 0.;
      m_qOverPratio = 1.;
      return;
    }
 
    trackPars.parameters()[eBoundQOverP] =
        hypot.qOverP(pAfter, trackPars.charge());
    // std::cout<<"Update q/p from " << qOverPBefore << " to " <<
    // trackPars.parameters()[eBoundQOverP] << std::endl; cache the derivative
    // of q/p with respect to energy loss for the Gx2f system and the qoverp
    // ratio before and after
    //  we are gonna need them for the bVecror and aMatrix for measurements
    //  after material surfaces the residuals of which depend on the updated q/p
    //  value after the energy loss
    m_qOverPderiv = trackPars.charge() / Acts::square(pAfter);
    m_qOverPratio =
        Acts::square(trackPars.parameters()[eBoundQOverP] / qOverPBefore);
  }
}

Member Data Documentation

◆ m_eloss

ELossAtSurface MuonExperimental::Gx2fMaterialProperties::m_eloss {}

private

Description of the energy loss.

Definition at line 208 of file Chi2Fitter.h.

208{};

◆ m_lostEnergy

double MuonExperimental::Gx2fMaterialProperties::m_lostEnergy {0.}

private

Fitted parameters.

Fitted energy loss at the surface

Definition at line 215 of file Chi2Fitter.h.

215{0.};

◆ m_qOverPderiv

double MuonExperimental::Gx2fMaterialProperties::m_qOverPderiv {0.}

private

qOverP derivative with respect to eloss

Definition at line 221 of file Chi2Fitter.h.

221{0.};

◆ m_qOverPratio

double MuonExperimental::Gx2fMaterialProperties::m_qOverPratio {1.}

private

Definition at line 223 of file Chi2Fitter.h.

223{1.};

◆ m_scatPhi

double MuonExperimental::Gx2fMaterialProperties::m_scatPhi {0.}

private

Fitted delta phi scattering.

Definition at line 219 of file Chi2Fitter.h.

219{0.};

◆ m_scatterer

ScatteringAtSurface MuonExperimental::Gx2fMaterialProperties::m_scatterer {}

private

Description of the scattering angles.

Definition at line 206 of file Chi2Fitter.h.

206{};

◆ m_scatTheta

double MuonExperimental::Gx2fMaterialProperties::m_scatTheta {0.}

private

Fitted delta theta scattering.

Definition at line 217 of file Chi2Fitter.h.

217{0.};

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

Classes

Public Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ Gx2fMaterialProperties()

Member Function Documentation

◆ contributionToGx2fSums()

◆ deltaPhi()

◆ deltaTheta()

◆ energyLoss()

◆ lostEnergy()

◆ materialIsValid()

◆ nDim()

◆ qOverPderiv()

◆ qOverPratio()

◆ scatterer()

◆ updateParameters()

◆ updateTrackParameters()

Member Data Documentation

◆ m_eloss

◆ m_lostEnergy

◆ m_qOverPderiv

◆ m_qOverPratio

◆ m_scatPhi

◆ m_scatterer

◆ m_scatTheta