CSCCathodeLCTAnalyzer.cc

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#include "FWCore/Utilities/interface/Exception.h"
#include "FWCore/MessageLogger/interface/MessageLogger.h"
#include "Geometry/CSCGeometry/interface/CSCGeometry.h"
#include "Geometry/CSCGeometry/interface/OffsetRadialStripTopology.h"
#include "L1Trigger/CSCTriggerPrimitives/plugins/CSCCathodeLCTAnalyzer.h"

using namespace std;

//-----------------
// Static variables
//-----------------

bool CSCCathodeLCTAnalyzer::debug = true;
bool CSCCathodeLCTAnalyzer::doME1A = false;

vector<CSCCathodeLayerInfo> CSCCathodeLCTAnalyzer::getSimInfo(const CSCCLCTDigi& clct,
                                                              const CSCDetId& clctId,
                                                              const CSCComparatorDigiCollection* compdc,
                                                              const edm::PSimHitContainer* allSimHits) {
  // Fills vector of CSCCathodeLayerInfo objects.  There can be up to 6 such
  // objects (one per layer); they contain the list of comparator digis used to
  // build a given CLCT, and the list of associated (closest) SimHits.
  // Filling is done in two steps: first, we construct the list of comparator
  // digis; next, find associated SimHits.
  vector<CSCCathodeLayerInfo> clctInfo = lctDigis(clct, clctId, compdc);

  // Sanity checks.
  if (clctInfo.size() > CSCConstants::NUM_LAYERS) {
    throw cms::Exception("CSCCathodeLCTAnalyzer") << "+++ Number of CSCCathodeLayerInfo objects, " << clctInfo.size()
                                                  << ", exceeds max expected, " << CSCConstants::NUM_LAYERS << " +++\n";
  }
  //  not a good check for high PU
  //if (clctInfo.size() != (unsigned)clct.getQuality()) {
  //  edm::LogWarning("L1CSCTPEmulatorWrongValues")
  //    << "+++ Warning: mismatch between CLCT quality, " << clct.getQuality()
  //    << ", and the number of layers with digis, " << clctInfo.size()
  //    << ", in clctInfo! +++\n";
  //}

  // Find the closest SimHit to each Digi.
  vector<CSCCathodeLayerInfo>::iterator pcli;
  for (pcli = clctInfo.begin(); pcli != clctInfo.end(); pcli++) {
    digiSimHitAssociator(*pcli, allSimHits);
  }

  return clctInfo;
}

vector<CSCCathodeLayerInfo> CSCCathodeLCTAnalyzer::lctDigis(const CSCCLCTDigi& clct,
                                                            const CSCDetId& clctId,
                                                            const CSCComparatorDigiCollection* compdc) {
  // Function to find a list of ComparatorDigis used to create an LCT.
  // The list of ComparatorDigis is stored in a class called CSCLayerInfo which
  // contains the layerId's of the stored ComparatorDigis as well as the actual
  // digis themselves.
  int hfstripDigis[CSCConstants::NUM_HALF_STRIPS];
  int time[CSCConstants::MAX_NUM_STRIPS], comp[CSCConstants::MAX_NUM_STRIPS];
  int digiNum[CSCConstants::MAX_NUM_STRIPS];
  int digiId = -999;
  CSCCathodeLayerInfo tempInfo;
  vector<CSCCathodeLayerInfo> vectInfo;

  // Inquire the clct for its key half-strip, strip type and pattern number.
  int clct_keystrip = clct.getKeyStrip();
  int clct_stripType = clct.getStripType();
  int clct_pattern = clct.getPattern();
  int clct_bx = clct.getBX();

  // Re-scale the key di-strip number to the count used in the search.
  if (clct_stripType == 0)
    clct_keystrip /= 4;

  if (debug) {
    char stype = (clct_stripType == 0) ? 'D' : 'H';
    LogDebug("lctDigis") << "\nlctDigis: CLCT keystrip = " << clct_keystrip << " (" << stype << ")"
                         << " pattern = " << clct_pattern << "; Id:"
                         << " endcap " << clctId.endcap() << ", station " << clctId.station() << ", ring "
                         << clctId.ring() << ", chamber " << clctId.chamber();
  }

  // 'Staggering' for key layer.  Needed for TMB07 version.
  const int key_layer = 3;  // counting from 1.
  CSCDetId layerId(clctId.endcap(), clctId.station(), clctId.ring(), clctId.chamber(), key_layer);
  const CSCLayer* csclayer = geom_->layer(layerId);
  int key_stagger = (csclayer->geometry()->stagger() + 1) / 2;

  for (int i_layer = 0; i_layer < CSCConstants::NUM_LAYERS; i_layer++) {
    // Clear tempInfo values every iteration before using.
    tempInfo.clear();

    // @ Switch to maps eventually
    vector<CSCComparatorDigi> digiMap;
    int digi_num = 0;
    for (int i_hstrip = 0; i_hstrip < CSCConstants::NUM_HALF_STRIPS; i_hstrip++) {
      hfstripDigis[i_hstrip] = -999;
    }
    for (int i_strip = 0; i_strip < CSCConstants::MAX_NUM_STRIPS; i_strip++) {
      time[i_strip] = -999;
      comp[i_strip] = 0;
      digiNum[i_strip] = -999;
    }

    // CLCTs belong to a chamber, so their layerId is 0.  Comparator digis
    // belong to layers, so in order to access them we need to add layer
    // number to CLCT's endcap, chamber, etc.
    CSCDetId layerId(clctId.endcap(), clctId.station(), clctId.ring(), clctId.chamber(), i_layer + 1);

    // Preselection of Digis: right layer and bx.
    digi_num += preselectDigis(clct_bx, layerId, compdc, digiMap, hfstripDigis, time, comp, digiNum);

    // In case of ME1/1, one can also look for digis in ME1/A.
    // Skip them for now since the resolution of CLCTs in ME1/A is
    // terrible (strips are ganged; channel numbers translated to be
    // in CFEB=4).
    if (doME1A) {
      if (clctId.station() == 1 && clctId.ring() == 1) {
        CSCDetId layerId_me1a(clctId.endcap(), clctId.station(), 4, clctId.chamber(), i_layer + 1);
        digi_num += preselectDigis(clct_bx, layerId_me1a, compdc, digiMap, hfstripDigis, time, comp, digiNum);
      }
    }

    // Loop over all the strips in a pattern.
    int max_pattern_strips, layer, strip;
    max_pattern_strips = CSCConstants::MAX_HALFSTRIPS_IN_PATTERN;
    for (int i_strip = 0; i_strip < max_pattern_strips; i_strip++) {
      layer = CSCPatternBank::clct_pattern[clct_pattern][i_strip];
      if (layer == i_layer) {
        strip = clct_keystrip + key_stagger + CSCPatternBank::clct_pattern_offset[i_strip];
        if (strip >= 0 && strip < CSCConstants::NUM_HALF_STRIPS) {
          digiId = hfstripDigis[strip];
          // halfstripDigis contains the digi numbers
          // that were carried through the different transformations
          // to keystrip. -999 means there was no Digi.
          if (digiId >= 0) {
            tempInfo.setId(layerId);                 // store the layer of this object
            tempInfo.addComponent(digiMap[digiId]);  // and the RecDigi
            if (debug)
              LogTrace("lctDigis") << " Digi on CLCT: strip/comp/time " << digiMap[digiId];
          }
        }
      }
    }

    // Save results for each non-empty layer.
    if (tempInfo.getId().layer() != 0) {
      vectInfo.push_back(tempInfo);
    }
  }
  return vectInfo;
}

int CSCCathodeLCTAnalyzer::preselectDigis(const int clct_bx,
                                          const CSCDetId& layerId,
                                          const CSCComparatorDigiCollection* compdc,
                                          vector<CSCComparatorDigi>& digiMap,
                                          int hfstripDigis[CSCConstants::NUM_HALF_STRIPS],
                                          int time[CSCConstants::MAX_NUM_STRIPS],
                                          int comp[CSCConstants::MAX_NUM_STRIPS],
                                          int digiNum[CSCConstants::MAX_NUM_STRIPS]) {
  // Preselection of Digis: right layer and bx.
  int digi_num = 0;

  // Parameters defining time window for accepting hits; should come from
  // configuration file eventually.
  const int fifo_tbins = 12;
  const int hit_persist = 4;
  const int drift_delay = 2;

  // 'Staggering' for this layer.
  const CSCLayer* csclayer = geom_->layer(layerId);
  int stagger = (csclayer->geometry()->stagger() + 1) / 2;

  bool me1a = (layerId.station() == 1) && (layerId.ring() == 4);

  const CSCComparatorDigiCollection::Range rcompd = compdc->get(layerId);
  for (CSCComparatorDigiCollection::const_iterator digiIt = rcompd.first; digiIt != rcompd.second; ++digiIt) {
    if (debug)
      LogDebug("lctDigis") << "Comparator digi: layer " << layerId.layer() - 1
                           << " strip/comparator/time =" << (*digiIt);

    if ((*digiIt).getComparator() == 0 || (*digiIt).getComparator() == 1) {
      int bx_time = (*digiIt).getTimeBin();
      if (bx_time >= 0 && bx_time < fifo_tbins) {
        // Do not use digis which could not have contributed to a given CLCT.
        int latch_bx = clct_bx + drift_delay;
        if (bx_time <= latch_bx - hit_persist || bx_time > latch_bx) {
          if (debug)
            LogDebug("lctDigis") << "Late comparator digi: layer " << layerId.layer() - 1
                                 << " strip/comparator/time =" << (*digiIt) << " skipping...";
          continue;
        }

        // If there is more than one digi on the same strip, pick the one
        // which occurred earlier.
        int i_strip = (*digiIt).getStrip() - 1;  // starting from 0
        if (me1a && i_strip < 16) {
          // Move ME1/A comparators from CFEB=0 to CFEB=4 if this has not
          // been done already.
          i_strip += 64;
        }

        if (time[i_strip] <= 0 || time[i_strip] > bx_time) {
          // @ Switch to maps; check for match in time.
          int i_hfstrip = 2 * i_strip + (*digiIt).getComparator() + stagger;
          hfstripDigis[i_hfstrip] = digi_num;

          // Arrays for distrip stagger
          comp[i_strip] = (*digiIt).getComparator();
          time[i_strip] = bx_time;
          digiNum[i_strip] = digi_num;

          if (debug)
            LogDebug("lctDigis") << "digi_num = " << digi_num << " half-strip = " << i_hfstrip
                                 << " strip = " << i_strip;
        }
      }
    }
    digiMap.push_back(*digiIt);
    digi_num++;
  }

  return digi_num;
}

void CSCCathodeLCTAnalyzer::digiSimHitAssociator(CSCCathodeLayerInfo& info, const edm::PSimHitContainer* allSimHits) {
  // This routine matches up the closest simHit to every digi on a given layer.
  // Note that it is possible to have up to 2 digis contribute to an LCT
  // on a given layer. In a primitive algorithm used now more than one digi on
  // a layer can be associated with the same simHit.
  vector<PSimHit> simHits;

  vector<CSCComparatorDigi> thisLayerDigis = info.getRecDigis();
  if (!thisLayerDigis.empty()) {
    CSCDetId layerId = info.getId();
    bool me11 = (layerId.station() == 1) && (layerId.ring() == 1);

    // Get simHits in this layer.
    for (edm::PSimHitContainer::const_iterator simHitIt = allSimHits->begin(); simHitIt != allSimHits->end();
         simHitIt++) {
      // Find detId where simHit is located.
      CSCDetId hitId = (CSCDetId)(*simHitIt).detUnitId();
      if (hitId == layerId)
        simHits.push_back(*simHitIt);
      if (me11) {
        CSCDetId layerId_me1a(layerId.endcap(), layerId.station(), 4, layerId.chamber(), layerId.layer());
        if (hitId == layerId_me1a)
          simHits.push_back(*simHitIt);
      }
    }

    if (!simHits.empty()) {
      ostringstream strstrm;
      if (debug) {
        strstrm << "\nLayer " << layerId.layer() << " has " << simHits.size() << " SimHit(s); phi value(s) = ";
      }

      // Get the strip number for every digi and convert to phi.
      for (vector<CSCComparatorDigi>::iterator prd = thisLayerDigis.begin(); prd != thisLayerDigis.end(); prd++) {
        double deltaPhiMin = 999.;
        double bestHitPhi = 999.;
        PSimHit* bestHit = nullptr;

        int strip = prd->getStrip();
        double digiPhi = getStripPhi(layerId, strip - 0.5);

        const CSCLayer* csclayer = geom_->layer(layerId);
        for (vector<PSimHit>::iterator psh = simHits.begin(); psh != simHits.end(); psh++) {
          // Get the local phi for the simHit.
          LocalPoint hitLP = psh->localPosition();
          GlobalPoint hitGP = csclayer->toGlobal(hitLP);
          double hitPhi = hitGP.phi();
          if (debug)
            strstrm << hitPhi << " ";
          // Find the lowest deltaPhi and store the associated simHit.
          // Check to see if comparison is on pi border, and if so, make
          // corrections.
          double deltaPhi = 999.;
          if (fabs(hitPhi - digiPhi) < M_PI) {
            deltaPhi = fabs(hitPhi - digiPhi);
          } else {
            if (debug)
              LogDebug("digiSimHitAssociator") << "SimHit and Digi are close to edge!!!";
            deltaPhi = fabs(fabs(hitPhi - digiPhi) - 2. * M_PI);
          }
          if (deltaPhi < deltaPhiMin) {
            deltaPhiMin = deltaPhi;
            bestHit = &(*psh);
            bestHitPhi = hitPhi;
          }
        }
        if (debug) {
          strstrm << "\nDigi Phi: " << digiPhi << ", closest SimHit phi: " << bestHitPhi
                  << ", particle type: " << bestHit->particleType();
        }
        info.addComponent(*bestHit);
      }
      if (debug) {
        LogTrace("digiSimHitAssociator") << strstrm.str();
      }
    }
  }
}

int CSCCathodeLCTAnalyzer::nearestHS(const vector<CSCCathodeLayerInfo>& allLayerInfo,
                                     double& closestPhi,
                                     double& closestEta) {
  // Function to set the simulated values for comparison to the reconstructed.
  // It first tries to look for the SimHit in the key layer.  If it is
  // unsuccessful, it loops over all layers and looks for an associated
  // hit in any one of the layers.  First instance of a hit gives a calculation
  // for phi.
  int nearestHS = -999;
  PSimHit matchedHit;
  bool hit_found = false;
  CSCDetId layerId;
  static const int key_layer = CSCConstants::KEY_CLCT_LAYER;

  vector<CSCCathodeLayerInfo>::const_iterator pli;
  for (pli = allLayerInfo.begin(); pli != allLayerInfo.end(); pli++) {
    if (pli->getId().layer() == key_layer) {
      vector<PSimHit> thisLayerHits = pli->getSimHits();
      if (!thisLayerHits.empty()) {
        // There can be one RecDigi (and therefore only one SimHit)
        // in a keylayer.
        if (thisLayerHits.size() != 1) {
          edm::LogWarning("L1CSCTPEmulatorWrongValues")
              << "+++ Warning: " << thisLayerHits.size() << " SimHits in key layer " << key_layer << "! +++ \n";
          for (unsigned i = 0; i < thisLayerHits.size(); i++) {
            edm::LogWarning("L1CSCTPEmulatorWrongValues") << " SimHit # " << i << thisLayerHits[i] << "\n";
          }
        }
        matchedHit = thisLayerHits[0];
        layerId = pli->getId();
        hit_found = true;
        break;
      }
    }
  }

  if (hit_found == false) {
    for (pli = allLayerInfo.begin(); pli != allLayerInfo.end(); pli++) {
      // if there is any occurrence of simHit size greater that zero, use this.
      if (!(pli->getRecDigis()).empty() && !(pli->getSimHits()).empty()) {
        // Always use the first SimHit for now.
        matchedHit = (pli->getSimHits())[0];
        layerId = pli->getId();
        hit_found = true;
        break;
      }
    }
  }

  // Set phi and eta if there were any hits found.
  if (hit_found) {
    const CSCLayer* csclayer = geom_->layer(layerId);
    const CSCLayerGeometry* layerGeom = csclayer->geometry();
    //nearestStrip = layerGeom->nearestStrip(matchedHit.localPosition());
    // Float in units of the strip (angular) width.  From RadialStripTopology
    // comments: "Strip in which a given LocalPoint lies. This is a float
    // which represents the fractional strip position within the detector.
    // Returns zero if the LocalPoint falls at the extreme low edge of the
    // detector or BELOW, and float(nstrips) if it falls at the extreme high
    // edge or ABOVE."
    float strip = layerGeom->topology()->strip(matchedHit.localPosition());

    // Should be in the interval [0-MAX_STRIPS).  I see (rarely) cases when
    // strip = nearestStrip = MAX_STRIPS; do not know how to handle them.
    int nearestStrip = static_cast<int>(strip);
    if (nearestStrip < 0 || nearestStrip >= CSCConstants::MAX_NUM_STRIPS) {
      edm::LogWarning("L1CSCTPEmulatorWrongInput")
          << "+++ Warning: nearest strip, " << nearestStrip << ", is not in [0-" << CSCConstants::MAX_NUM_STRIPS
          << ") interval; strip = " << strip << " +++\n";
    }
    // Left/right half of the strip.
    int comp = ((strip - nearestStrip) < 0.5) ? 0 : 1;
    nearestHS = 2 * nearestStrip + comp;

    GlobalPoint thisPoint = csclayer->toGlobal(matchedHit.localPosition());
    closestPhi = thisPoint.phi();
    closestEta = thisPoint.eta();
    ostringstream strstrm;
    if (debug)
      strstrm << "Matched cathode phi: " << closestPhi;
    if (closestPhi < 0.) {
      closestPhi += 2. * M_PI;
      if (debug)
        strstrm << "(" << closestPhi << ")";
    }
    if (debug) {
      strstrm << " eta: " << closestEta << " on a layer " << layerId.layer() << " (1-6);"
              << " nearest strip: " << nearestStrip;
      LogDebug("nearestHS") << strstrm.str();
    }
  }

  return nearestHS;
}

void CSCCathodeLCTAnalyzer::setGeometry(const CSCGeometry* geom) { geom_ = geom; }

double CSCCathodeLCTAnalyzer::getStripPhi(const CSCDetId& layerId, const float strip) {
  // Returns phi position of a given strip.
  if (strip < 0. || strip >= CSCConstants::MAX_NUM_STRIPS) {
    edm::LogWarning("L1CSCTPEmulatorWrongInput")
        << "+++ Warning: strip, " << strip << ", is not in [0-" << CSCConstants::MAX_NUM_STRIPS << ") interval +++\n";
  }

  const CSCLayer* csclayer = geom_->layer(layerId);
  const CSCLayerGeometry* layerGeom = csclayer->geometry();

  // Position at the center of the strip.
  LocalPoint digiLP = layerGeom->topology()->localPosition(strip);
  // The alternative calculation gives exactly the same answer.
  // double ystrip = 0.0;
  // double xstrip = topology->xOfStrip(strip, ystrip);
  // LocalPoint  digiLP = LocalPoint(xstrip, ystrip);
  GlobalPoint digiGP = csclayer->toGlobal(digiLP);
  double phi = digiGP.phi();

  return phi;
}