DTLinearDriftFromDBAlgo.cc

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/*
 *  See header file for a description of this class.
 *
 *  \author S. Bolognesi - INFN Torino
 */

#include "RecoLocalMuon/DTRecHit/plugins/DTLinearDriftFromDBAlgo.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/Framework/interface/ESHandle.h"
#include "FWCore/Utilities/interface/Exception.h"
#include "CondFormats/DTObjects/interface/DTMtime.h"
#include "CondFormats/DataRecord/interface/DTMtimeRcd.h"

using namespace std;
using namespace edm;

DTLinearDriftFromDBAlgo::DTLinearDriftFromDBAlgo(const ParameterSet& config) :
  DTRecHitBaseAlgo(config),
  minTime(config.getParameter<double>("minTime")),
  maxTime(config.getParameter<double>("maxTime")),
  doVdriftCorr(config.getParameter<bool>("doVdriftCorr")),
  // Option to force going back to digi time at Step 2 
  stepTwoFromDigi(config.getParameter<bool>("stepTwoFromDigi")),
  // Set verbose output
  debug(config.getUntrackedParameter<bool>("debug"))
{
    if(debug)
      cout<<"[DTLinearDriftFromDBAlgo] Constructor called"<<endl;
  }



DTLinearDriftFromDBAlgo::~DTLinearDriftFromDBAlgo(){}



void DTLinearDriftFromDBAlgo::setES(const EventSetup& setup) {
  if(debug)
    cout<<"[DTLinearDriftFromDBAlgo] setES called"<<endl;
  theSync->setES(setup);
  // Get the map of ttrig from the Setup
  ESHandle<DTMtime> mTimeHandle;
  setup.get<DTMtimeRcd>().get(mTimeHandle);
  mTimeMap = &*mTimeHandle;
  
  if(debug) 
    cout << "[DTLinearDriftFromDBAlgo] meanTimer version: " << mTimeMap->version()<<endl;
}



// First Step
bool DTLinearDriftFromDBAlgo::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 (optionally, redo 1st step starting from digi time)
bool DTLinearDriftFromDBAlgo::compute(const DTLayer* layer,
                const DTRecHit1D& recHit1D,
                const float& angle,
                DTRecHit1D& newHit1D) const {

  if (!stepTwoFromDigi) {
    newHit1D.setPositionAndError(recHit1D.localPosition(), recHit1D.localPositionError());
    return true;
  }

  const DTWireId wireId = recHit1D.wireId();
  
  // Get Wire position
  if(!layer->specificTopology().isWireValid(wireId.wire())) return false;
  LocalPoint locWirePos(layer->specificTopology().wirePosition(wireId.wire()), 0, 0);
  const GlobalPoint globWirePos = layer->toGlobal(locWirePos);

  return compute(layer, wireId, recHit1D.digiTime(), globWirePos, newHit1D, 2);

}



// Third step.
bool DTLinearDriftFromDBAlgo::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 DTLinearDriftFromDBAlgo::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 << "[DTLinearDriftFromDBAlgo]*** 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;

  // Read the vDrift and reso for this wire
  float vDrift = 0;
  float hitResolution = 0;//FIXME: should use this!
  // vdrift is cm/ns , resolution is cm
  mTimeMap->get(wireId.superlayerId(),
            vDrift,
            hitResolution,
            DTVelocityUnits::cm_per_ns);

  //only in step 3
  if(doVdriftCorr && step == 3){
    if (abs(wireId.wheel()) == 2 && 
    wireId.station() == 1 &&
    wireId.superLayer() != 2) {
      // Variation of vdrift along Y due to B field, 
      // vdrift is lower  a negative Y (lower global |Z|)
      const float k_param = 1.2e-04;
      LocalPoint local_pos = layer->toLocal(globPos);
      vDrift = vDrift*(1. - k_param*local_pos.y());
    } 
  }

  // Compute the drift distance
  float drift = driftTime * vDrift;

  // 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 << "[DTLinearDriftFromDBAlgo] 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 DTLinearDriftFromDBAlgo::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") << "[DTLinearDriftFromDBAlgo] Compute at Step "
                        << step << ", Hit side "
                        << newHit1D.lrSide()
                        << " is invalid!" << endl;
      return false;
    }
      
    return true;
  }else {
    return false;
  }
}