TrajectoryState/src/TrajectoryStateClosestToPoint.cc

0001 #include "TrackingTools/TrajectoryState/interface/TrajectoryStateClosestToPoint.h"
0002 #include "FWCore/MessageLogger/interface/MessageLogger.h"
0003
0004 // Private constructor
0005
0006 TrajectoryStateClosestToPoint::TrajectoryStateClosestToPoint(const FTS& originalFTS, const GlobalPoint& referencePoint)
0007     : theFTS(originalFTS), theRefPoint(referencePoint), valid(true), theFTSavailable(true), errorIsAvailable(false) {
0008   auto params = PerigeeConversions::ftsToPerigeeParameters(originalFTS, referencePoint, thePt);
0009   if (not params) {
0010     valid = false;
0011     edm::LogInfo("TrajectoryStateClosestToPoint_PerigeeConversions") << "Track had pt == 0.";
0012     return;
0013   }
0014   theParameters = *params;
0015   if (theFTS.hasError()) {
0016     thePerigeeError = PerigeeConversions::ftsToPerigeeError(originalFTS);
0017     errorIsAvailable = true;
0018   }
0019   theField = &(originalFTS.parameters().magneticField());
0020 }
0021
0022 void TrajectoryStateClosestToPoint::calculateFTS() const {
0023   if (!isValid())
0024     throw TrajectoryStateException("TrajectoryStateClosestToPoint is invalid and cannot return any parameters");
0025   GlobalTrajectoryParameters gtp(PerigeeConversions::positionFromPerigee(theParameters, theRefPoint),
0026                                  PerigeeConversions::momentumFromPerigee(theParameters, thePt, theRefPoint),
0027                                  theParameters.charge(),
0028                                  theField);
0029   if (errorIsAvailable) {
0030     theFTS = FTS(gtp, PerigeeConversions::curvilinearError(thePerigeeError, gtp));
0031   } else {
0032     theFTS = FTS(gtp);
0033   }
0034   theFTSavailable = true;
0035 }