TsosGaussianStateConversions.cc

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#include "TrackingTools/GsfTracking/interface/TsosGaussianStateConversions.h"

#include "TrackingTools/GsfTools/interface/SingleGaussianState.h"
#include "TrackingTools/GsfTools/interface/BasicMultiTrajectoryState.h"

using namespace SurfaceSideDefinition;

namespace GaussianStateConversions {

  MultiGaussianState<5> multiGaussianStateFromTSOS (const TrajectoryStateOnSurface & tsos)
  {
    if ( !tsos.isValid() )  return MultiGaussianState<5>();

    using SingleStatePtr = std::shared_ptr<SingleGaussianState<5>>;
    auto const & components = tsos.components();
    MultiGaussianState<5>::SingleStateContainer singleStates;
    singleStates.reserve(components.size());
    for (auto const & ic : components) {
      if ( ic.isValid() ) {
    auto sgs = std::make_shared<SingleGaussianState<5>>(ic.localParameters().vector(),
                                  ic.localError().matrix(),
                                  ic.weight());
    singleStates.push_back(sgs);
      }
    }
    return MultiGaussianState<5>(singleStates);
  }

  TrajectoryStateOnSurface tsosFromMultiGaussianState (const MultiGaussianState<5>& multiState,
                              const TrajectoryStateOnSurface & refTsos)
  {
    if ( multiState.components().empty() )  return TrajectoryStateOnSurface();
    const Surface & surface = refTsos.surface();
    SurfaceSide side = refTsos.surfaceSide();
    const MagneticField* field = refTsos.magneticField();
    auto const & refTsos1 = refTsos.components().front();
    auto pzSign = refTsos1.localParameters().pzSign();
    bool charged = refTsos1.charge()!=0;

    auto const & singleStates = multiState.components();
    std::vector<TrajectoryStateOnSurface> components;
    components.reserve(singleStates.size());
    for ( auto const & ic : singleStates ) {
      components.emplace_back((*ic).weight(), 
                              LocalTrajectoryParameters((*ic).mean(), pzSign,charged),
                            LocalTrajectoryError((*ic).covariance()),
                          surface,field,side);
    }
    return TrajectoryStateOnSurface((BasicTrajectoryState*)new BasicMultiTrajectoryState(components));
  }
}