ComponentParameters.cxx

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/*
  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
*/
 
//
#include "TrkParameters/ComponentParameters.h"
 
Trk::MultiComponentState
Trk::MultiComponentStateHelpers::clone(const Trk::MultiComponentState& in)
{
  auto clonedState = Trk::MultiComponentState();
  clonedState.reserve(in.size());
  for (const ComponentParameters& component : in) {
    clonedState.push_back({component.params->uniqueClone(), component.weight});
  }
  return clonedState;
}
 
Trk::MultiComponentState
Trk::MultiComponentStateHelpers::WithScaledError(Trk::MultiComponentState&& in,
                                                 double errorScaleLocX,
                                                 double errorScaleLocY,
                                                 double errorScalePhi,
                                                 double errorScaleTheta,
                                                 double errorScaleQoverP)
{
  AmgSymMatrix(5) coefficients;
  coefficients(0, 0) = (errorScaleLocX * errorScaleLocX);
  coefficients(1, 1) = (errorScaleLocY * errorScaleLocY);
  coefficients(2, 2) = (errorScalePhi * errorScalePhi);
  coefficients(3, 3) = (errorScaleTheta * errorScaleTheta);
  coefficients(4, 4) = (errorScaleQoverP * errorScaleQoverP);
  coefficients.fillSymmetric(0, 1, (errorScaleLocX * errorScaleLocY));
  coefficients.fillSymmetric(0, 2, (errorScaleLocX * errorScalePhi));
  coefficients.fillSymmetric(0, 3, (errorScaleLocX * errorScaleTheta));
  coefficients.fillSymmetric(0, 4, (errorScaleLocX * errorScaleQoverP));
  coefficients.fillSymmetric(1, 2, (errorScaleLocY * errorScalePhi));
  coefficients.fillSymmetric(1, 3, (errorScaleLocY * errorScaleTheta));
  coefficients.fillSymmetric(1, 4, (errorScaleLocY * errorScaleQoverP));
  coefficients.fillSymmetric(2, 3, (errorScalePhi * errorScaleTheta));
  coefficients.fillSymmetric(2, 4, (errorScalePhi * errorScaleQoverP));
  coefficients.fillSymmetric(3, 4, (errorScaleTheta * errorScaleQoverP));
 
  for (ComponentParameters& component : in) {
    Trk::TrackParameters* trackParameters = component.params.get();
    const AmgSymMatrix(5)* originalMatrix = trackParameters->covariance();
    // If no covariance skip
    if (!originalMatrix) {
      continue;
    }
    AmgSymMatrix(5) newCovarianceMatrix =
      (*originalMatrix).cwiseProduct(coefficients);
    trackParameters->updateParameters(trackParameters->parameters(),
                                      newCovarianceMatrix);
  }
  return { std::move(in) };
}
 
bool
Trk::MultiComponentStateHelpers::allHaveCovariance(const Trk::MultiComponentState& in)
{
  bool allHaveCovariance = true;
  for (const ComponentParameters& component : in) {
    const AmgSymMatrix(5)* originalMatrix = component.params->covariance();
    if (!originalMatrix) {
      allHaveCovariance = false;
      break;
    }
  }
  return allHaveCovariance;
}
 
void
Trk::MultiComponentStateHelpers::renormaliseState(Trk::MultiComponentState& in,
                                                  double norm)
{
  // Determine total weighting of state
  double sumWeights = 0.;
  for (const ComponentParameters& component : in) {
    sumWeights += component.weight;
  }
  if (sumWeights == 0) {
    return;
  }
  double normalise = norm / sumWeights;
  for (ComponentParameters& component : in) {
    component.weight = component.weight * normalise;
  }
}