BasicMultiTrajectoryState.cc

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

#include "DataFormats/GeometrySurface/interface/BoundPlane.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"

using namespace SurfaceSideDefinition;

BasicMultiTrajectoryState::BasicMultiTrajectoryState( const std::vector<TSOS>& tsvec) :
  BasicTrajectoryState(tsvec.front().surface()), theStates(tsvec) {
 
  // only accept planes!!
  const BoundPlane* bp = dynamic_cast<const BoundPlane*>(&tsvec.begin()->surface());
  if UNLIKELY( bp==nullptr )
           throw cms::Exception("LogicError") << "MultiTrajectoryState constructed on cylinder";
   
  for (auto i=tsvec.begin(); i!=tsvec.end(); i++) {
    if UNLIKELY(!i->isValid()) {
      throw cms::Exception("LogicError") << "MultiTrajectoryState constructed with invalid state";
    }
    if UNLIKELY(i->hasError() != tsvec.front().hasError()) {
      throw cms::Exception("LogicError") << "MultiTrajectoryState mixes states with and without errors";
    }
    if UNLIKELY( &i->surface() != &tsvec.front().surface()) {
      throw cms::Exception("LogicError") << "MultiTrajectoryState mixes states with different surfaces";
    }
    if UNLIKELY( i->surfaceSide() != tsvec.front().surfaceSide()) {
      throw cms::Exception("LogicError") 
    << "MultiTrajectoryState mixes states defined before and after material";
    }
    if UNLIKELY( i->localParameters().pzSign()*tsvec.front().localParameters().pzSign()<0. ) {
      throw cms::Exception("LogicError") 
    << "MultiTrajectoryState mixes states with different signs of local p_z";
    }

  }
  //
  combine();
}



void BasicMultiTrajectoryState::rescaleError(double factor) {

  if UNLIKELY(theStates.empty()) {
    edm::LogError("BasicMultiTrajectoryState") << "Trying to rescale errors of empty MultiTrajectoryState!";
    return;
  }
  
  for (auto & is : theStates) is.rescaleError(factor);
  combine();
}

void
BasicMultiTrajectoryState::combine()  {
  const std::vector<TrajectoryStateOnSurface>& tsos = theStates;

  if UNLIKELY(tsos.empty()) {
    edm::LogError("MultiTrajectoryStateCombiner") 
      << "Trying to collapse empty set of trajectory states!";
    return;
  }

  double pzSign = tsos.front().localParameters().pzSign();
  for (std::vector<TrajectoryStateOnSurface>::const_iterator it = tsos.begin(); 
       it != tsos.end(); it++) {
    if UNLIKELY(it->localParameters().pzSign() != pzSign) {
      edm::LogError("MultiTrajectoryStateCombiner") 
    << "Trying to collapse trajectory states with different signs on p_z!";
      return;
    }
  }
  
  if UNLIKELY(tsos.size() == 1) {
    BasicTrajectoryState::update(tsos.front().weight(),
                                 tsos.front().localParameters(), 
                 tsos.front().localError(), 
                 tsos.front().surface(), 
                 tsos.front().magneticField(),
                 tsos.front().surfaceSide()
                 );
    return;
  }
  
  double sumw = 0.;
  //int dim = tsos.front().localParameters().vector().num_row();
  AlgebraicVector5 mean;
  AlgebraicSymMatrix55 covarPart1, covarPart2, covtmp;
  for (auto it1 = tsos.begin(); it1 != tsos.end(); it1++) {
    auto weight = it1->weight();
    auto const & param = it1->localParameters().vector();
    sumw += weight;
    mean += weight * param;
    covarPart1 += weight * it1->localError().matrix();
    for (auto it2 = it1 + 1; it2 != tsos.end(); it2++) {
      AlgebraicVector5 diff = param - it2->localParameters().vector();
      ROOT::Math::AssignSym::Evaluate(covtmp,ROOT::Math::TensorProd(diff,diff));
      covarPart2 += (weight * it2->weight()) * covtmp;
    }   
  }
  double sumwI = 1.0/sumw;
  mean *= sumwI;
  covarPart1 *= sumwI; covarPart2 *= (sumwI*sumwI);
  AlgebraicSymMatrix55 covar = covarPart1 + covarPart2;

  BasicTrajectoryState::update(sumw,
                               LocalTrajectoryParameters(mean, pzSign), 
                   LocalTrajectoryError(covar), 
                   tsos.front().surface(), 
                   tsos.front().magneticField(),
                   tsos.front().surfaceSide()
                              );
}

void
BasicMultiTrajectoryState::
update( const LocalTrajectoryParameters& p,
        const Surface& aSurface,
        const MagneticField* field,
        const SurfaceSide side) 
{
  throw cms::Exception("LogicError", 
                       "BasicMultiTrajectoryState::update(LocalTrajectoryParameters, Surface, ...) called even if canUpdateLocalParameters() is false");
}

void
BasicMultiTrajectoryState::
update( double weight,
        const LocalTrajectoryParameters& p,
        const LocalTrajectoryError& err,
        const Surface& aSurface,
        const MagneticField* field,
        const SurfaceSide side)
{
  throw cms::Exception("LogicError", 
                       "BasicMultiTrajectoryState::update(LocalTrajectoryParameters, LocalTrajectoryError, ...) called even if canUpdateLocalParameters() is false");
}