DTLinearDriftAlgo.cc

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/*
 *  See header file for a description of this class.
 *
 *  \author G. Cerminara - INFN Torino
 */
 
#include "RecoLocalMuon/DTRecHit/plugins/DTLinearDriftAlgo.h"
#include "CalibMuon/DTDigiSync/interface/DTTTrigBaseSync.h"
#include "DataFormats/MuonDetId/interface/DTWireId.h"
#include "Geometry/DTGeometry/interface/DTLayer.h"
#include "FWCore/ParameterSet/interface/ParameterSet.h"
#include "FWCore/Framework/interface/EventSetup.h"
#include "FWCore/Utilities/interface/Exception.h"
 
using namespace std;
using namespace edm;
 
DTLinearDriftAlgo::DTLinearDriftAlgo(const ParameterSet& config)
    : DTRecHitBaseAlgo(config),
      // Get the Drift Velocity from parameter set.
      vDrift(config.getParameter<double>("driftVelocity")),         // FIXME: Default was 0.00543 cm/ns
      hitResolution(config.getParameter<double>("hitResolution")),  // FIXME: Default is
      // vDriftMB1W1(config.getParameter<double>("driftVelocityMB1W1")), // FIXME: Default was 0.00543 cm/ns
      minTime(config.getParameter<double>("minTime")),  // FIXME: Default was -3 ns
      maxTime(config.getParameter<double>("maxTime")),  // FIXME: Default was 415 ns
      // Set verbose output
      debug(config.getUntrackedParameter<bool>("debug")) {}
 
DTLinearDriftAlgo::~DTLinearDriftAlgo() {}
 
void DTLinearDriftAlgo::setES(const EventSetup& setup) { theSync->setES(setup); }
 
// First Step
bool DTLinearDriftAlgo::compute(
    const DTLayer* layer, const DTDigi& digi, LocalPoint& leftPoint, LocalPoint& rightPoint, LocalError& error) const {
  // Get the wireId
  DTLayerId layerId = layer->id();
  const DTWireId wireId(layerId, digi.wire());
 
  // Get Wire position
  if (!layer->specificTopology().isWireValid(digi.wire()))
    return false;
  LocalPoint locWirePos(layer->specificTopology().wirePosition(digi.wire()), 0, 0);
  const GlobalPoint globWirePos = layer->toGlobal(locWirePos);
 
  return compute(layer, wireId, digi.time(), globWirePos, leftPoint, rightPoint, error, 1);
}
 
// Second step: the same as 1st step
bool DTLinearDriftAlgo::compute(const DTLayer* layer,
                                const DTRecHit1D& recHit1D,
                                const float& angle,
                                DTRecHit1D& newHit1D) const {
  newHit1D.setPositionAndError(recHit1D.localPosition(), recHit1D.localPositionError());
  return true;
}
 
// Third step.
bool DTLinearDriftAlgo::compute(const DTLayer* layer,
                                const DTRecHit1D& recHit1D,
                                const float& angle,
                                const GlobalPoint& globPos,
                                DTRecHit1D& newHit1D) const {
  return compute(layer, recHit1D.wireId(), recHit1D.digiTime(), globPos, newHit1D, 3);
}
 
// Do the actual work.
bool DTLinearDriftAlgo::compute(const DTLayer* layer,
                                const DTWireId& wireId,
                                const float digiTime,
                                const GlobalPoint& globPos,
                                LocalPoint& leftPoint,
                                LocalPoint& rightPoint,
                                LocalError& error,
                                int step) const {
  // Subtract the offset to the digi time accordingly to the DTTTrigBaseSync concrete instance
  float driftTime = digiTime - theSync->offset(layer, wireId, globPos);
 
  // check for out-of-time
  if (driftTime < minTime || driftTime > maxTime) {
    if (debug)
      cout << "[DTLinearDriftAlgo]*** Drift time out of window for in-time hits " << driftTime << endl;
 
    if (step == 1) {  //FIXME: protection against failure at 2nd and 3rd steps, must be checked!!!
      // Hits are interpreted as coming from out-of-time pile-up and recHit
      // is ignored.
      return false;
    }
  }
 
  // Small negative times interpreted as hits close to the wire.
  if (driftTime < 0.)
    driftTime = 0;
 
  // Compute the drift distance
  // SL 21-Dec-2006: Use specific Drift for MB1W1 (non fluxed chamber)
  float vd = vDrift;
  // if (wireId.wheel()==1 && wireId.station()==1) {
  //   vd=vDriftMB1W1;
  //   //cout << "Using Vd " << vd<< endl;
  // }
 
  float drift = driftTime * vd;
 
  // Get Wire position
  if (!layer->specificTopology().isWireValid(wireId.wire()))
    return false;
  LocalPoint locWirePos(layer->specificTopology().wirePosition(wireId.wire()), 0, 0);
  //Build the two possible points and the error on the position
  leftPoint = LocalPoint(locWirePos.x() - drift, locWirePos.y(), locWirePos.z());
  rightPoint = LocalPoint(locWirePos.x() + drift, locWirePos.y(), locWirePos.z());
  error = LocalError(hitResolution * hitResolution, 0., 0.);
 
  if (debug) {
    cout << "[DTLinearDriftAlgo] Compute drift distance, for digi at wire: " << wireId << endl
         << "       Step:           " << step << endl
         << "       Digi time:      " << digiTime << endl
         << "       Drift time:     " << driftTime << endl
         << "       Drift distance: " << drift << endl
         << "       Hit Resolution: " << hitResolution << endl
         << "       Left point:     " << leftPoint << endl
         << "       Right point:    " << rightPoint << endl
         << "       Error:          " << error << endl;
  }
 
  return true;
}
 
// Interface to the method which does the actual work suited for 2nd and 3rd steps
bool DTLinearDriftAlgo::compute(const DTLayer* layer,
                                const DTWireId& wireId,
                                const float digiTime,
                                const GlobalPoint& globPos,
                                DTRecHit1D& newHit1D,
                                int step) const {
  LocalPoint leftPoint;
  LocalPoint rightPoint;
  LocalError error;
 
  if (compute(layer, wireId, digiTime, globPos, leftPoint, rightPoint, error, step)) {
    // Set the position and the error of the rechit which is being updated
    switch (newHit1D.lrSide()) {
      case DTEnums::Left: {
        // Keep the original y position of newHit1D: for step==3, it's the
        // position along the wire. Needed for rotation alignment
        LocalPoint leftPoint3D(leftPoint.x(), newHit1D.localPosition().y(), leftPoint.z());
        newHit1D.setPositionAndError(leftPoint3D, error);
        break;
      }
 
      case DTEnums::Right: {
        // as above: 3d position
        LocalPoint rightPoint3D(rightPoint.x(), newHit1D.localPosition().y(), rightPoint.z());
        newHit1D.setPositionAndError(rightPoint3D, error);
        break;
      }
 
      default:
        throw cms::Exception("InvalidDTCellSide") << "[DTLinearDriftAlgo] Compute at Step " << step << ", Hit side "
                                                  << newHit1D.lrSide() << " is invalid!" << endl;
        return false;
    }
 
    return true;
  } else {
    return false;
  }
}