/data/refman/pasoursint/CMSSW_4_1_8_patch12/src/TrackingTools/GsfTracking/src/GsfMaterialEffectsUpdator.cc

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

#include "TrackingTools/GsfTools/interface/MultiTrajectoryStateAssembler.h"
#include "TrackingTools/TrajectoryState/interface/SurfaceSideDefinition.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"
#include "FWCore/Utilities/interface/Exception.h"
//
// Update of the trajectory state (implemented in base class since general for
//   all classes returning deltaPs and deltaCovs.
//

using namespace SurfaceSideDefinition;

TrajectoryStateOnSurface 
GsfMaterialEffectsUpdator::updateState (const TrajectoryStateOnSurface& TSoS, 
                                        const PropagationDirection propDir) const {
  //
  // get components of input state and check if material is associated to surface
  //
  const Surface& surface = TSoS.surface();
  if ( !surface.mediumProperties() )  return TSoS;
  SurfaceSide side = propDir==alongMomentum ? afterSurface : beforeSurface;
  // single input state?
  if ( TSoS.components().size()>1 )
    throw cms::Exception("LogicError") << "GsfMaterialEffectsUpdator::updateState used with MultiTSOS";
  double weight = TSoS.weight();
  //
  // Get components (will force recalculation, if necessary)
  //
  std::vector<double> Ws = weights(TSoS,propDir);
  if ( Ws.empty() )  return TrajectoryStateOnSurface();
  std::vector<double> dPs = deltaPs(TSoS,propDir);
  if ( dPs.size()!=Ws.size() )
    throw cms::Exception("LogicError") 
      << "GsfMaterialEffectsUpdator: inconsistency in number of components";  
  std::vector<AlgebraicSymMatrix55> deltaErrors;
  if ( TSoS.hasError() )
    deltaErrors = deltaLocalErrors(TSoS,propDir);
  //
  // prepare output vector
  //
  MultiTrajectoryStateAssembler result;
  //
  // loop over components
  //
  //   edm::LogDebug("GsfMaterialEffectsUpdator") << "found " << Ws.size() << " components\n"
  //                                         << "  input state has weight " << TSoS.weight();
  for ( unsigned int ic=0; ic<Ws.size(); ic++ ) {
    //      edm::LogDebug("GsfMaterialEffectsUpdator") << "w, dp, sigp = "
    //           << Ws[ic] << ", "
    //           << dPs[ic] << ", "
    //           << sqrt((deltaErrors[ic])[0][0]);
    //
    // Update momentum. In case of failure: return invalid state.
    // Use deltaP method to ensure update of cache, if necessary!
    //
    LocalTrajectoryParameters lp = TSoS.localParameters();
    if ( !lp.updateP(dPs[ic]) )  
      return TrajectoryStateOnSurface();
    //
    // Update covariance matrix?
    //
    if ( TSoS.hasError() ) {
      AlgebraicSymMatrix55 eloc = TSoS.localError().matrix();
      eloc += deltaErrors[ic];
      result.addState(TrajectoryStateOnSurface(lp,
                                               LocalTrajectoryError(eloc),
                                               surface,
                                               &(TSoS.globalParameters().magneticField()),
                                               side,
                                               weight*Ws[ic]));
      //       edm::LogDebug("GsfMaterialEffectsUpdator") 
      //        << "adding state with weight " << weight*Ws[ic];
    }
    else {
      result.addState(TrajectoryStateOnSurface(lp,surface,
                                               &(TSoS.globalParameters().magneticField()),
                                               side));
    }
  }
  //   edm::LogDebug("GsfMaterialEffectsUpdator") 
  //     << "  output state has weight " << result.combinedState().weight();
  return result.combinedState();
}