/data/refman/pasoursint/CMSSW_5_3_1/src/TrackingTools/TrajectoryState/src/TrajectoryStateClosestToPoint.cc

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#include "TrackingTools/TrajectoryState/interface/TrajectoryStateClosestToPoint.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"

// Private constructor

TrajectoryStateClosestToPoint::
TrajectoryStateClosestToPoint(const FTS& originalFTS, const GlobalPoint& referencePoint) :
  valid(true), theFTS(originalFTS), theFTSavailable(true), theRefPoint(referencePoint)
{
  try {
      theParameters = perigeeConversions.ftsToPerigeeParameters(originalFTS, referencePoint, thePt);
      if (theFTS.hasError()) {
        thePerigeeError = perigeeConversions.ftsToPerigeeError(originalFTS);
        errorIsAvailable = true;
      } 
      else {
        errorIsAvailable = false;
      }
      theField = &(originalFTS.parameters().magneticField());
  } catch (const cms::Exception &ex) {
      if (ex.category() != "PerigeeConversions") throw;
      edm::LogWarning("TrajectoryStateClosestToPoint_PerigeeConversions") << "Caught exception " << ex.explainSelf() << ".\n";
      valid = false;
  }
}


TrajectoryStateClosestToPoint::
TrajectoryStateClosestToPoint(const PerigeeTrajectoryParameters& perigeeParameters, double pt,
  const GlobalPoint& referencePoint, const MagneticField* field) :
    valid(true), theField(field), theFTSavailable(false), theRefPoint(referencePoint), 
    theParameters(perigeeParameters), thePt( pt ), errorIsAvailable(false)
{}

TrajectoryStateClosestToPoint::
TrajectoryStateClosestToPoint(const PerigeeTrajectoryParameters& perigeeParameters, double pt,
  const PerigeeTrajectoryError& perigeeError, const GlobalPoint& referencePoint,
  const MagneticField* field):
    valid(true), theField(field), theFTSavailable(false), theRefPoint(referencePoint),
    theParameters(perigeeParameters), thePt( pt ), thePerigeeError(perigeeError),
    errorIsAvailable(true)
    
{}


void TrajectoryStateClosestToPoint::calculateFTS() const
{
  if(!isValid()) throw TrajectoryStateException(
        "TrajectoryStateClosestToPoint is invalid and cannot return any parameters");
  GlobalTrajectoryParameters gtp(
            perigeeConversions.positionFromPerigee(theParameters, theRefPoint),
            perigeeConversions.momentumFromPerigee(theParameters, thePt, theRefPoint),
            theParameters.charge(), theField);
  if (errorIsAvailable) {
    theFTS = FTS(gtp, perigeeConversions.curvilinearError(thePerigeeError, gtp));
  } else {
    theFTS = FTS(gtp);
  }
  theFTSavailable = true;
}