RPixPlaneCombinatoryTracking.cc

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#include "RecoPPS/Local/interface/RPixPlaneCombinatoryTracking.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"
 
#include <algorithm>
#include <cmath>
 
#include "DataFormats/Math/interface/Error.h"
#include "DataFormats/Math/interface/AlgebraicROOTObjects.h"
#include "CondFormats/PPSObjects/interface/CTPPSPixelIndices.h"
#include "TMath.h"
 
#include "DataFormats/CTPPSReco/interface/CTPPSPixelLocalTrackRecoInfo.h"
 
//------------------------------------------------------------------------------------------------//
 
RPixPlaneCombinatoryTracking::RPixPlaneCombinatoryTracking(edm::ParameterSet const &parameterSet)
    : RPixDetTrackFinder(parameterSet) {
  trackMinNumberOfPoints_ = parameterSet.getParameter<uint>("trackMinNumberOfPoints");
  verbosity_ = parameterSet.getUntrackedParameter<int>("verbosity");
  maximumChi2OverNDF_ = parameterSet.getParameter<double>("maximumChi2OverNDF");
  maximumXLocalDistanceFromTrack_ = parameterSet.getParameter<double>("maximumXLocalDistanceFromTrack");
  maximumYLocalDistanceFromTrack_ = parameterSet.getParameter<double>("maximumYLocalDistanceFromTrack");
  numberOfPlanesPerPot_ = parameterSet.getParameter<int>("numberOfPlanesPerPot");
 
  if (trackMinNumberOfPoints_ < 3) {
    throw cms::Exception("RPixPlaneCombinatoryTracking")
        << "Minimum number of planes required for tracking is 3, "
        << "tracking is not possible with " << trackMinNumberOfPoints_ << " hits";
  }
}
 
//------------------------------------------------------------------------------------------------//
 
RPixPlaneCombinatoryTracking::~RPixPlaneCombinatoryTracking() { possiblePlaneCombinations_.clear(); }
 
//------------------------------------------------------------------------------------------------//
 
void RPixPlaneCombinatoryTracking::initialize() {
  uint32_t numberOfCombinations =
      factorial(numberOfPlanesPerPot_) /
      (factorial(numberOfPlanesPerPot_ - trackMinNumberOfPoints_) * factorial(trackMinNumberOfPoints_));
  if (verbosity_ >= 2)
    edm::LogInfo("RPixPlaneCombinatoryTracking") << "Number of combinations = " << numberOfCombinations;
  possiblePlaneCombinations_.reserve(numberOfCombinations);
 
  getPlaneCombinations(listOfAllPlanes_, trackMinNumberOfPoints_, possiblePlaneCombinations_);
 
  if (verbosity_ >= 2) {
    for (const auto &vec : possiblePlaneCombinations_) {
      for (const auto &num : vec) {
        edm::LogInfo("RPixPlaneCombinatoryTracking") << num << " - ";
      }
      edm::LogInfo("RPixPlaneCombinatoryTracking");
    }
  }
}
 
//------------------------------------------------------------------------------------------------//
 
//This function produces all the possible plane combinations extracting numberToExtract planes over numberOfPlanes planes
void RPixPlaneCombinatoryTracking::getPlaneCombinations(const std::vector<uint32_t> &inputPlaneList,
                                                        uint32_t numberToExtract,
                                                        PlaneCombinations &planeCombinations) const {
  uint32_t numberOfPlanes = inputPlaneList.size();
  std::string bitmask(numberToExtract, 1);  // numberToExtract leading 1's
  bitmask.resize(numberOfPlanes, 0);        // numberOfPlanes-numberToExtract trailing 0's
  planeCombinations.clear();
 
  // store the combination and permute bitmask
  do {
    planeCombinations.push_back(std::vector<uint32_t>());
    for (uint32_t i = 0; i < numberOfPlanes; ++i) {  // [0..numberOfPlanes-1] integers
      if (bitmask[i])
        planeCombinations.back().push_back(inputPlaneList.at(i));
    }
  } while (std::prev_permutation(bitmask.begin(), bitmask.end()));
 
  return;
}
 
//------------------------------------------------------------------------------------------------//
 
//This function calls it self in order to get all the possible combinations of hits having a certain selected number of planes
//This function avoids to write for loops in cascade which will not allow to define arbitrarily the minimum number of planes to use
//The output is stored in a map containing the vector of points and as a key the map of the point forming this vector.
//This allows to erase the points already used for the track fit
void RPixPlaneCombinatoryTracking::getHitCombinations(const std::map<CTPPSPixelDetId, PointInPlaneList> &mapOfAllHits,
                                                      std::map<CTPPSPixelDetId, PointInPlaneList>::iterator mapIterator,
                                                      HitReferences tmpHitPlaneMap,
                                                      const PointInPlaneList &tmpHitVector,
                                                      PointAndReferenceMap &outputMap) {
  //At this point I selected one hit per plane
  if (mapIterator == mapOfAllHits.end()) {
    outputMap[tmpHitPlaneMap] = tmpHitVector;
    return;
  }
  for (size_t i = 0; i < mapIterator->second.size(); i++) {
    HitReferences newHitPlaneMap = tmpHitPlaneMap;
    newHitPlaneMap[mapIterator->first] = i;
    PointInPlaneList newVector = tmpHitVector;
    newVector.push_back(mapIterator->second[i]);
    std::map<CTPPSPixelDetId, PointInPlaneList>::iterator tmpMapIterator = mapIterator;
    getHitCombinations(mapOfAllHits, ++tmpMapIterator, newHitPlaneMap, newVector, outputMap);
  }
}
 
//------------------------------------------------------------------------------------------------//
 
RPixPlaneCombinatoryTracking::PointAndReferenceMap RPixPlaneCombinatoryTracking::produceAllHitCombination(
    PlaneCombinations inputPlaneCombination) {
  PointAndReferenceMap mapOfAllPoints;
  CTPPSPixelDetId tmpRpId = romanPotId_;  //in order to avoid to modify the data member
 
  if (verbosity_ >= 2)
    edm::LogInfo("RPixPlaneCombinatoryTracking") << "Searching for all combinations...";
  //Loop on all the plane combinations
  for (const auto &planeCombination : inputPlaneCombination) {
    std::map<CTPPSPixelDetId, PointInPlaneList> selectedCombinationHitOnPlane;
    bool allPlaneAsHits = true;
 
    //Loop on all the possible combinations
    //In this loop the selectedCombinationHitOnPlane is filled
    //and cases in which one of the selected plane is empty are skipped
    for (const auto &plane : planeCombination) {
      tmpRpId.setPlane(plane);
      CTPPSPixelDetId planeDetId = tmpRpId;
      if (hitMap_->find(planeDetId) == hitMap_->end()) {
        if (verbosity_ >= 2)
          edm::LogInfo("RPixPlaneCombinatoryTracking")
              << "No data on arm " << planeDetId.arm() << " station " << planeDetId.station() << " rp "
              << planeDetId.rp() << " plane " << planeDetId.plane();
        allPlaneAsHits = false;
        break;
      }
      if (selectedCombinationHitOnPlane.find(planeDetId) != selectedCombinationHitOnPlane.end()) {
        throw cms::Exception("RPixPlaneCombinatoryTracking")
            << "selectedCombinationHitOnPlane contains already detId " << planeDetId
            << "Error in the algorithm which created all the possible plane combinations";
      }
      selectedCombinationHitOnPlane[planeDetId] = (*hitMap_)[planeDetId];
    }
    if (!allPlaneAsHits)
      continue;
 
    //I add the all the hit combinations to the full list of plane combinations
    auto mapIterator = selectedCombinationHitOnPlane.begin();
    HitReferences tmpHitPlaneMap;   //empty map of plane id and hit number needed the getHitCombinations algorithm
    PointInPlaneList tmpHitVector;  //empty vector of hits needed for the getHitCombinations algorithm
    getHitCombinations(selectedCombinationHitOnPlane, mapIterator, tmpHitPlaneMap, tmpHitVector, mapOfAllPoints);
    if (verbosity_ >= 2)
      edm::LogInfo("RPixPlaneCombinatoryTracking") << "Number of possible tracks " << mapOfAllPoints.size();
 
  }  //end of loops on all the combinations
 
  return mapOfAllPoints;
}
 
//------------------------------------------------------------------------------------------------//
 
void RPixPlaneCombinatoryTracking::findTracks(int run) {
  //The loop search for all the possible tracks starting from the one with the smallest chiSquare/NDF
  //The loop stops when the number of planes with recorded hits is less than the minimum number of planes required
  //or if the track with minimum chiSquare found has a chiSquare higher than the maximum required
 
  while (hitMap_->size() >= trackMinNumberOfPoints_) {
    if (verbosity_ >= 1)
      edm::LogInfo("RPixPlaneCombinatoryTracking") << "Number of plane with hits " << hitMap_->size();
    if (verbosity_ >= 2)
      for (const auto &plane : *hitMap_)
        edm::LogInfo("RPixPlaneCombinatoryTracking")
            << "\tarm " << plane.first.arm() << " station " << plane.first.station() << " rp " << plane.first.rp()
            << " plane " << plane.first.plane() << " : " << plane.second.size();
 
    //I create the map of all the possible combinations of a group of trackMinNumberOfPoints_ points
    //and the key keeps the reference of which planes and which hit numbers form the combination
    PointAndReferenceMap mapOfAllMinRequiredPoint;
    //I produce the map for all cominations of all hits with all trackMinNumberOfPoints_ plane combinations
    mapOfAllMinRequiredPoint = produceAllHitCombination(possiblePlaneCombinations_);
 
    //Fit all the possible combinations with minimum number of planes required and find the track with minimum chi2
    double theMinChiSquaredOverNDF = maximumChi2OverNDF_ + 1.;  //in order to break the loop in case no track is found;
    HitReferences pointMapWithMinChiSquared;
    PointInPlaneList pointsWithMinChiSquared;
    CTPPSPixelLocalTrack bestTrack;
 
    if (verbosity_ >= 2)
      edm::LogInfo("RPixPlaneCombinatoryTracking")
          << "Number of combinations of trackMinNumberOfPoints_ planes " << mapOfAllMinRequiredPoint.size();
    for (const auto &pointsAndRef : mapOfAllMinRequiredPoint) {
      CTPPSPixelLocalTrack tmpTrack = fitTrack(pointsAndRef.second);
      double tmpChiSquaredOverNDF = tmpTrack.chiSquaredOverNDF();
      if (verbosity_ >= 2)
        edm::LogInfo("RPixPlaneCombinatoryTracking") << "ChiSquare of the present track " << tmpChiSquaredOverNDF;
      if (!tmpTrack.isValid() || tmpChiSquaredOverNDF > maximumChi2OverNDF_ || tmpChiSquaredOverNDF == 0.)
        continue;  //validity check
      if (tmpChiSquaredOverNDF < theMinChiSquaredOverNDF) {
        theMinChiSquaredOverNDF = tmpChiSquaredOverNDF;
        pointMapWithMinChiSquared = pointsAndRef.first;
        pointsWithMinChiSquared = pointsAndRef.second;
        bestTrack = tmpTrack;
      }
    }
 
    //The loop on the fit of all tracks is done, the track with minimum chiSquared is found
    // and it is verified that it complies with the maximumChi2OverNDF_ requirement
    if (theMinChiSquaredOverNDF > maximumChi2OverNDF_)
      break;
 
    //The list of planes not included in the minimum chiSquare track is produced.
    std::vector<uint32_t> listOfExcludedPlanes;
    for (const auto &plane : listOfAllPlanes_) {
      CTPPSPixelDetId tmpRpId = romanPotId_;  //in order to avoid to modify the data member
      tmpRpId.setPlane(plane);
      CTPPSPixelDetId planeDetId = tmpRpId;
      if (pointMapWithMinChiSquared.find(planeDetId) == pointMapWithMinChiSquared.end())
        listOfExcludedPlanes.push_back(plane);
    }
 
    //I produce all the possible combinations of planes to be added to the track,
    //excluding the case of no other plane added since it has been already fitted.
    PlaneCombinations planePointedHitListCombination;
    for (uint32_t i = 1; i <= listOfExcludedPlanes.size(); ++i) {
      PlaneCombinations tmpPlaneCombination;
      getPlaneCombinations(listOfExcludedPlanes, i, tmpPlaneCombination);
      for (const auto &combination : tmpPlaneCombination)
        planePointedHitListCombination.push_back(combination);
    }
 
    //I produce all the possible combinations of points to be added to the track
    PointAndReferenceMap mapOfAllPointWithAtLeastBestFitSelected;
    PointAndReferenceMap mapOfPointCombinationToBeAdded;
    mapOfPointCombinationToBeAdded = produceAllHitCombination(planePointedHitListCombination);
    //The found hit combination is added to the hits selected by the best fit;
    for (const auto &element : mapOfPointCombinationToBeAdded) {
      HitReferences newPointMap = pointMapWithMinChiSquared;
      PointInPlaneList newPoints = pointsWithMinChiSquared;
      for (const auto &pointRef : element.first)
        newPointMap[pointRef.first] = pointRef.second;  //add the new point reference
      for (const auto &point : element.second)
        newPoints.push_back(point);
      mapOfAllPointWithAtLeastBestFitSelected[newPointMap] = newPoints;
    }
 
    //I fit all the possible combination of the minimum plane best fit hits plus hits from the other planes
    if (verbosity_ >= 1)
      edm::LogInfo("RPixPlaneCombinatoryTracking")
          << "Minimum chiSquare over NDF for all the tracks " << theMinChiSquaredOverNDF;
 
    // I look for the tracks with maximum number of points with a chiSquare over NDF smaller than maximumChi2OverNDF_
    // If more than one track fulfill the chiSquare requirement with the same number of points I choose the one with smaller chiSquare
    std::vector<PointAndReferencePair> orderedVectorOfAllPointWithAtLeastBestFitSelected =
        orderCombinationsPerNumberOrPoints(mapOfAllPointWithAtLeastBestFitSelected);
    int currentNumberOfPlanes = 0;
    theMinChiSquaredOverNDF = maximumChi2OverNDF_ + 1.;  //in order to break the loop in case no track is found;
    bool foundTrackWithCurrentNumberOfPlanes = false;
    for (const auto &pointsAndRef : orderedVectorOfAllPointWithAtLeastBestFitSelected) {
      int tmpNumberOfPlanes = pointsAndRef.second.size();
      // If a valid track has been already found with an higher number of planes the loop stops.
      if (foundTrackWithCurrentNumberOfPlanes && tmpNumberOfPlanes < currentNumberOfPlanes)
        break;
      CTPPSPixelLocalTrack tmpTrack = fitTrack(pointsAndRef.second);
      double tmpChiSquaredOverNDF = tmpTrack.chiSquaredOverNDF();
      if (!tmpTrack.isValid() || tmpChiSquaredOverNDF > maximumChi2OverNDF_ || tmpChiSquaredOverNDF == 0.)
        continue;  //validity check
      if (tmpChiSquaredOverNDF < theMinChiSquaredOverNDF) {
        theMinChiSquaredOverNDF = tmpChiSquaredOverNDF;
        pointMapWithMinChiSquared = pointsAndRef.first;
        bestTrack = tmpTrack;
        currentNumberOfPlanes = tmpNumberOfPlanes;
        foundTrackWithCurrentNumberOfPlanes = true;
      }
    }
 
    if (verbosity_ >= 1)
      edm::LogInfo("RPixPlaneCombinatoryTracking") << "The best track has " << bestTrack.ndf() / 2 + 2;
 
    std::vector<uint32_t> listOfPlaneNotUsedForFit = listOfAllPlanes_;
    //remove the hits belonging to the tracks from the full list of hits
    for (const auto &hitToErase : pointMapWithMinChiSquared) {
      std::map<CTPPSPixelDetId, PointInPlaneList>::iterator hitMapElement = hitMap_->find(hitToErase.first);
      if (hitMapElement == hitMap_->end()) {
        throw cms::Exception("RPixPlaneCombinatoryTracking")
            << "The found tracks has hit belonging to a plane which does not have hits";
      }
      std::vector<uint32_t>::iterator planeIt;
      planeIt = std::find(listOfPlaneNotUsedForFit.begin(), listOfPlaneNotUsedForFit.end(), hitToErase.first.plane());
      listOfPlaneNotUsedForFit.erase(planeIt);
      hitMapElement->second.erase(hitMapElement->second.begin() + hitToErase.second);
      //if the plane at which the hit was erased is empty it is removed from the hit map
      if (hitMapElement->second.empty())
        hitMap_->erase(hitMapElement);
    }
 
    //search for hit on the other planes which may belong to the same track
    //even if they did not contributed to the track
    //in case of multiple hit, the closest one to the track will be considered
    //If a hit is found these will not be erased from the list of all hits
    //If no hit is found, the point on the plane intersecting the track will be saved by a CTPPSPixelFittedRecHit
    //with the isRealHit_ flag set to false
    for (const auto &plane : listOfPlaneNotUsedForFit) {
      CTPPSPixelDetId tmpPlaneId = romanPotId_;  //in order to avoid to modify the data member
      tmpPlaneId.setPlane(plane);
      std::unique_ptr<CTPPSPixelFittedRecHit> fittedRecHit(new CTPPSPixelFittedRecHit());
      GlobalPoint pointOnDet;
      calculatePointOnDetector(&bestTrack, tmpPlaneId, pointOnDet);
 
      if (hitMap_->find(tmpPlaneId) != hitMap_->end()) {
        //I convert the hit search window defined in local coordinated into global
        //This avoids to convert the global plane-line intersection in order not to call the the geometry
        math::Vector<3>::type maxGlobalPointDistance(
            maximumXLocalDistanceFromTrack_, maximumYLocalDistanceFromTrack_, 0.);
 
        DetGeomDesc::RotationMatrix theRotationMatrix = geometry_->sensor(tmpPlaneId)->rotation();
        AlgebraicMatrix33 tmpPlaneRotationMatrixMap;
        theRotationMatrix.GetComponents(tmpPlaneRotationMatrixMap(0, 0),
                                        tmpPlaneRotationMatrixMap(0, 1),
                                        tmpPlaneRotationMatrixMap(0, 2),
                                        tmpPlaneRotationMatrixMap(1, 0),
                                        tmpPlaneRotationMatrixMap(1, 1),
                                        tmpPlaneRotationMatrixMap(1, 2),
                                        tmpPlaneRotationMatrixMap(2, 0),
                                        tmpPlaneRotationMatrixMap(2, 1),
                                        tmpPlaneRotationMatrixMap(2, 2));
 
        maxGlobalPointDistance = tmpPlaneRotationMatrixMap * maxGlobalPointDistance;
        //I avoid the Sqrt since it will not be saved
        double maximumXdistance = maxGlobalPointDistance[0] * maxGlobalPointDistance[0];
        double maximumYdistance = maxGlobalPointDistance[1] * maxGlobalPointDistance[1];
        // to be sure that the first min distance is from a real point
        double minimumDistance = 1. + maximumXdistance + maximumYdistance;
        for (const auto &hit : (*hitMap_)[tmpPlaneId]) {
          double xResidual = hit.globalPoint.x() - pointOnDet.x();
          double yResidual = hit.globalPoint.y() - pointOnDet.y();
          double xDistance = xResidual * xResidual;
          double yDistance = yResidual * yResidual;
          double distance = xDistance + yDistance;
          if (xDistance < maximumXdistance && yDistance < maximumYdistance && distance < minimumDistance) {
            LocalPoint residuals(xResidual, yResidual, 0.);
            math::Error<3>::type globalError = hit.globalError;
            LocalPoint pulls(xResidual / std::sqrt(globalError[0][0]), yResidual / std::sqrt(globalError[1][1]), 0.);
            fittedRecHit.reset(new CTPPSPixelFittedRecHit(hit.recHit, pointOnDet, residuals, pulls));
            fittedRecHit->setIsRealHit(true);
          }
        }
      } else {
        LocalPoint fakePoint;
        LocalError fakeError;
        CTPPSPixelRecHit fakeRecHit(fakePoint, fakeError);
        fittedRecHit.reset(new CTPPSPixelFittedRecHit(fakeRecHit, pointOnDet, fakePoint, fakePoint));
      }
 
      bestTrack.addHit(tmpPlaneId, *fittedRecHit);
    }
 
    localTrackVector_.push_back(bestTrack);
 
    int pointForTracking = 0;
    int pointOnTrack = 0;
 
    if (verbosity_ >= 1) {
      for (const auto &planeHits : bestTrack.hits()) {
        for (const auto &fittedhit : planeHits) {
          if (fittedhit.isUsedForFit())
            ++pointForTracking;
          if (fittedhit.isRealHit())
            ++pointOnTrack;
        }
      }
      edm::LogInfo("RPixPlaneCombinatoryTracking")
          << "Best track has " << pointForTracking << " points used for the fit and " << pointOnTrack
          << " points belonging to the track\n";
    }
 
  }  //close of the while loop on all the hits
 
  // recoInfo_ calculation
  // Hardcoded shift periods:
  // Before run 300802: No shift
  // Starting from run 300802: Sec45 St2 Rp3 Pl 0,2,3 ROC 0 shifted.
  // Starting from run 303338: No shift.
  // Starting from run 305169: Sec45 St2 Rp3 Pl 1,3,5 ROC 0 shifted.
  // Starting from run 305965: Sec45 St2 Rp3 Pl 1,3,5 ROC 0 shifted & Sec56 St2 Rp3 Pl 2,4,5 ROC 5 shifted.
  // Starting from run 307083: No shift
 
  // These variables hold the information of the runs when the detector was taking data in 3+3 Mode and which planes were bx-shifted
  // These values will never be changed and the 3+3 Mode will never be used again in the future
  const CTPPSPixelDetId rpId_arm0_st2 = CTPPSPixelDetId(0, 2, 3);
  const CTPPSPixelDetId rpId_arm1_st2 = CTPPSPixelDetId(1, 2, 3);
  static const std::map<unsigned int, std::map<CTPPSPixelDetId, std::vector<bool> > > isPlaneShifted = {
      {0,
       {
           {rpId_arm0_st2, {false, false, false, false, false, false}},  // Shift Period 0 Sec45
           {rpId_arm1_st2, {false, false, false, false, false, false}}   // Shift Period 1 Sec56
       }},
      {300802,
       {
           {rpId_arm0_st2, {true, false, true, true, false, false}},    // Shift Period 1 Sec45
           {rpId_arm1_st2, {false, false, false, false, false, false}}  // Shift Period 1 Sec56
       }},
      {303338,
       {
           {rpId_arm0_st2, {false, false, false, false, false, false}},  // Shift Period 2 Sec45
           {rpId_arm1_st2, {false, false, false, false, false, false}}   // Shift Period 2 Sec56
       }},
      {305169,
       {
           {rpId_arm0_st2, {false, true, false, true, false, true}},    // Shift Period 3 Sec45
           {rpId_arm1_st2, {false, false, false, false, false, false}}  // Shift Period 3 Sec56
       }},
      {305965,
       {
           {rpId_arm0_st2, {false, true, false, true, false, true}},  // Shift Period 4 Sec45
           {rpId_arm1_st2, {false, false, true, false, true, true}}   // Shift Period 4 Sec56
       }},
      {307083,
       {
           {rpId_arm0_st2, {false, false, false, false, false, false}},  // Shift Period 0 Sec45
           {rpId_arm1_st2, {false, false, false, false, false, false}}   // Shift Period 1 Sec56
       }}};                                                              // map< shiftedPeriod, map<DetID,shiftScheme> >
  const auto &shiftStatusInitialRun = std::prev(isPlaneShifted.upper_bound(run));
  unsigned short shiftedROC = 10;
  CTPPSPixelIndices pixelIndices;
 
  // Selecting the shifted ROC
  if (romanPotId_.arm() == 0)
    shiftedROC = 0;
  if (romanPotId_.arm() == 1)
    shiftedROC = 5;
 
  // Loop over found tracks to set recoInfo_
  for (auto &track : localTrackVector_) {
    if (romanPotId_ != rpId_arm0_st2 && romanPotId_ != rpId_arm1_st2) {
      track.setRecoInfo(CTPPSpixelLocalTrackReconstructionInfo::notShiftedRun);
      if (verbosity_ >= 2)
        edm::LogInfo("RPixPlaneCombinatoryTracking") << "Analyzing run: " << run << "\nTrack belongs to Arm "
                                                     << romanPotId_.arm() << " Station " << romanPotId_.station();
 
      continue;
    }
    unsigned short bxShiftedPlanesUsed = 0;
    unsigned short bxNonShiftedPlanesUsed = 0;
    unsigned short hitInShiftedROC = 0;
 
    auto const &fittedHits = track.hits();
    auto const &planeFlags = (shiftStatusInitialRun->second).at(romanPotId_);
 
    for (const auto &planeHits : fittedHits) {
      unsigned short plane = CTPPSPixelDetId(planeHits.detId()).plane();
      for (const auto &hit : planeHits) {
        if (hit.isUsedForFit()) {
          if (pixelIndices.getROCId(hit.minPixelCol(), hit.minPixelRow()) == shiftedROC)
            hitInShiftedROC++;  // Count how many hits are in the shifted ROC
          if (planeFlags.at(plane))
            bxShiftedPlanesUsed++;  // Count how many bx-shifted planes are used
          else if (planeFlags != std::vector<bool>(6, false))
            bxNonShiftedPlanesUsed++;  // Count how many non-bx-shifted planes are used, only if there are shifted planes
        }
      }
    }
 
    // Set recoInfo_ value
    track.setRecoInfo(CTPPSpixelLocalTrackReconstructionInfo::
                          invalid);  // Initially setting it as invalid. It has to match one of the following options.
    if (hitInShiftedROC < 3)
      track.setRecoInfo(CTPPSpixelLocalTrackReconstructionInfo::notShiftedRun);
    else {
      if (bxShiftedPlanesUsed == 0 && bxNonShiftedPlanesUsed == 0)
        track.setRecoInfo(
            CTPPSpixelLocalTrackReconstructionInfo::notShiftedRun);  // Default value for runs without bx-shift
      if (bxShiftedPlanesUsed == 3 && bxNonShiftedPlanesUsed == 0)
        track.setRecoInfo(CTPPSpixelLocalTrackReconstructionInfo::
                              allShiftedPlanes);  // Track reconstructed in a shifted ROC, only with bx-shifted planes
      if (bxShiftedPlanesUsed == 0 && bxNonShiftedPlanesUsed == 3)
        // Track reconstructed in a shifted ROC, only with non-bx-shifted planes
        track.setRecoInfo(CTPPSpixelLocalTrackReconstructionInfo::noShiftedPlanes);
      if (bxShiftedPlanesUsed > 0 && bxNonShiftedPlanesUsed > 0)
        track.setRecoInfo(CTPPSpixelLocalTrackReconstructionInfo::
                              mixedPlanes);  // Track reconstructed in a shifted ROC, with mixed planes
    }
    if (bxShiftedPlanesUsed + bxNonShiftedPlanesUsed > 6) {
      throw cms::Exception("RPixPlaneCombinatoryTracking") << "Error in RPixPlaneCombinatoryTracking::findTracks -> "
                                                           << "More than six points found for a track, skipping.";
      continue;
    }
    if (track.recoInfo() == CTPPSpixelLocalTrackReconstructionInfo::invalid) {
      throw cms::Exception("RPixPlaneCombinatoryTracking") << "Error in RPixPlaneCombinatoryTracking::findTracks -> "
                                                           << "recoInfo has not been set properly.";
    }
 
    if (verbosity_ >= 2) {
      edm::LogInfo("RPixPlaneCombinatoryTracking")
          << " Track belongs to Arm " << romanPotId_.arm() << " Station " << romanPotId_.station()
          << "\nFirst run with this bx-shift configuration: " << shiftStatusInitialRun->first
          << "\nTrack reconstructed with: " << bxShiftedPlanesUsed << " bx-shifted planes, " << bxNonShiftedPlanesUsed
          << " non-bx-shifted planes, " << hitInShiftedROC << " hits in the bx-shifted ROC"
          << "\nrecoInfo = " << (unsigned short)track.recoInfo();
      if (planeFlags != std::vector<bool>(6, false))
        edm::LogInfo("RPixPlaneCombinatoryTracking") << "The shifted ROC is ROC" << shiftedROC;
    }
  }
  return;
}
 
//------------------------------------------------------------------------------------------------//
 
CTPPSPixelLocalTrack RPixPlaneCombinatoryTracking::fitTrack(PointInPlaneList pointList) {
  uint32_t const numberOfPlanes = 6;
  math::Vector<2 * numberOfPlanes>::type xyCoordinates;
  math::Error<2 * numberOfPlanes>::type varianceMatrix;
  math::Matrix<2 * numberOfPlanes, 4>::type zMatrix;
 
  //The matrices and vector xyCoordinates, varianceMatrix and varianceMatrix are built from the points
  for (uint32_t iHit = 0; iHit < numberOfPlanes; iHit++) {
    if (iHit < pointList.size()) {
      const auto &globalPoint = pointList[iHit].globalPoint;
      xyCoordinates[2 * iHit] = globalPoint.x();
      xyCoordinates[2 * iHit + 1] = globalPoint.y();
      zMatrix(2 * iHit, 0) = 1.;
      zMatrix(2 * iHit, 2) = globalPoint.z() - z0_;
      zMatrix(2 * iHit + 1, 1) = 1.;
      zMatrix(2 * iHit + 1, 3) = globalPoint.z() - z0_;
 
      AlgebraicMatrix33 globalError = pointList[iHit].globalError;
      varianceMatrix(2 * iHit, 2 * iHit) = globalError(0, 0);
      varianceMatrix(2 * iHit, 2 * iHit + 1) = globalError(0, 1);
      varianceMatrix(2 * iHit + 1, 2 * iHit) = globalError(1, 0);
      varianceMatrix(2 * iHit + 1, 2 * iHit + 1) = globalError(1, 1);
    } else {
      varianceMatrix(2 * iHit, 2 * iHit) = 1.;
      varianceMatrix(2 * iHit + 1, 2 * iHit + 1) = 1.;
    }
  }
 
  //Get real point variance matrix
  if (!varianceMatrix.Invert()) {
    edm::LogError("RPixPlaneCombinatoryTracking") << "Error in RPixPlaneCombinatoryTracking::fitTrack -> "
                                                  << "Point variance matrix is singular, skipping.";
    CTPPSPixelLocalTrack badTrack;
    badTrack.setValid(false);
    return badTrack;
  }
 
  math::Error<4>::type covarianceMatrix = ROOT::Math::SimilarityT(zMatrix, varianceMatrix);
 
  //To have the real parameter covariance matrix, covarianceMatrix needs to be inverted
  if (!covarianceMatrix.Invert()) {
    edm::LogError("RPixPlaneCombinatoryTracking") << "Error in RPixPlaneCombinatoryTracking::fitTrack -> "
                                                  << "Parameter covariance matrix is singular, skipping.";
    CTPPSPixelLocalTrack badTrack;
    badTrack.setValid(false);
    return badTrack;
  }
 
  // track parameters: (x0, y0, tx, ty); x = x0 + tx*(z-z0)
  math::Vector<4>::type zMatrixTransposeTimesVarianceMatrixTimesXyCoordinates =
      ROOT::Math::Transpose(zMatrix) * varianceMatrix * xyCoordinates;
  math::Vector<4>::type parameterVector = covarianceMatrix * zMatrixTransposeTimesVarianceMatrixTimesXyCoordinates;
  math::Vector<2 *numberOfPlanes>::type xyCoordinatesMinusZmatrixTimesParameters =
      xyCoordinates - (zMatrix * parameterVector);
 
  double chiSquare = ROOT::Math::Dot(xyCoordinatesMinusZmatrixTimesParameters,
                                     (varianceMatrix * xyCoordinatesMinusZmatrixTimesParameters));
 
  CTPPSPixelLocalTrack goodTrack(z0_, parameterVector, covarianceMatrix, chiSquare);
  goodTrack.setValid(true);
 
  for (const auto &hit : pointList) {
    const auto &globalPoint = hit.globalPoint;
    GlobalPoint pointOnDet;
    bool foundPoint = calculatePointOnDetector(&goodTrack, hit.detId, pointOnDet);
    if (!foundPoint) {
      CTPPSPixelLocalTrack badTrack;
      badTrack.setValid(false);
      return badTrack;
    }
    double xResidual = globalPoint.x() - pointOnDet.x();
    double yResidual = globalPoint.y() - pointOnDet.y();
    LocalPoint residuals(xResidual, yResidual);
 
    math::Error<3>::type globalError(hit.globalError);
    LocalPoint pulls(xResidual / std::sqrt(globalError(0, 0)), yResidual / std::sqrt(globalError(0, 0)));
 
    CTPPSPixelFittedRecHit fittedRecHit(hit.recHit, pointOnDet, residuals, pulls);
    fittedRecHit.setIsUsedForFit(true);
    goodTrack.addHit(hit.detId, fittedRecHit);
  }
 
  return goodTrack;
}
 
//------------------------------------------------------------------------------------------------//
 
//The method calculates the hit pointed by the track on the detector plane
bool RPixPlaneCombinatoryTracking::calculatePointOnDetector(CTPPSPixelLocalTrack *track,
                                                            CTPPSPixelDetId planeId,
                                                            GlobalPoint &planeLineIntercept) {
  double z0 = track->z0();
  CTPPSPixelLocalTrack::ParameterVector parameters = track->parameterVector();
 
  math::Vector<3>::type pointOnLine(parameters[0], parameters[1], z0);
  GlobalVector tmpLineUnitVector = track->directionVector();
  math::Vector<3>::type lineUnitVector(tmpLineUnitVector.x(), tmpLineUnitVector.y(), tmpLineUnitVector.z());
 
  const CTPPSGeometry::Vector tmpPointLocal(0., 0., 0.);
  const auto &tmpPointOnPlane = geometry_->localToGlobal(planeId, tmpPointLocal);
 
  math::Vector<3>::type pointOnPlane(tmpPointOnPlane.x(), tmpPointOnPlane.y(), tmpPointOnPlane.z());
  math::Vector<3>::type planeUnitVector(0., 0., 1.);
 
  DetGeomDesc::RotationMatrix theRotationMatrix = geometry_->sensor(planeId)->rotation();
  AlgebraicMatrix33 tmpPlaneRotationMatrixMap;
  theRotationMatrix.GetComponents(tmpPlaneRotationMatrixMap(0, 0),
                                  tmpPlaneRotationMatrixMap(0, 1),
                                  tmpPlaneRotationMatrixMap(0, 2),
                                  tmpPlaneRotationMatrixMap(1, 0),
                                  tmpPlaneRotationMatrixMap(1, 1),
                                  tmpPlaneRotationMatrixMap(1, 2),
                                  tmpPlaneRotationMatrixMap(2, 0),
                                  tmpPlaneRotationMatrixMap(2, 1),
                                  tmpPlaneRotationMatrixMap(2, 2));
 
  planeUnitVector = tmpPlaneRotationMatrixMap * planeUnitVector;
 
  double denominator = ROOT::Math::Dot(lineUnitVector, planeUnitVector);
  if (denominator == 0) {
    edm::LogError("RPixPlaneCombinatoryTracking")
        << "Error in RPixPlaneCombinatoryTracking::calculatePointOnDetector -> "
        << "Fitted line and plane are parallel. Removing this track";
    return false;
  }
 
  double distanceFromLinePoint = ROOT::Math::Dot((pointOnPlane - pointOnLine), planeUnitVector) / denominator;
 
  math::Vector<3>::type tmpPlaneLineIntercept = distanceFromLinePoint * lineUnitVector + pointOnLine;
  planeLineIntercept = GlobalPoint(tmpPlaneLineIntercept[0], tmpPlaneLineIntercept[1], tmpPlaneLineIntercept[2]);
 
  return true;
}
//------------------------------------------------------------------------------------------------//
 
// The method sorts the possible point combinations in order to process before fits on the highest possible number of points
std::vector<RPixPlaneCombinatoryTracking::PointAndReferencePair>
RPixPlaneCombinatoryTracking::orderCombinationsPerNumberOrPoints(PointAndReferenceMap inputMap) {
  std::vector<PointAndReferencePair> sortedVector(inputMap.begin(), inputMap.end());
  std::sort(sortedVector.begin(), sortedVector.end(), functionForPlaneOrdering);
 
  return sortedVector;
}
//------------------------------------------------------------------------------------------------//