CAHitQuadrupletGenerator.cc

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#include <functional>

#include "CommonTools/Utils/interface/DynArray.h"
#include "DataFormats/Common/interface/Handle.h"
#include "FWCore/Framework/interface/ConsumesCollector.h"
#include "FWCore/Framework/interface/Event.h"
#include "FWCore/ParameterSet/interface/ParameterSetDescription.h"
#include "FWCore/Utilities/interface/isFinite.h"
#include "RecoPixelVertexing/PixelTriplets/interface/CAHitQuadrupletGenerator.h"
#include "RecoPixelVertexing/PixelTriplets/interface/ThirdHitPredictionFromCircle.h"
#include "TrackingTools/DetLayers/interface/BarrelDetLayer.h"

#include "CAGraph.h"
#include "CellularAutomaton.h"

namespace
{
  template <typename T>
  T sqr(T x)
  {
    return x * x;
  }
}

using namespace std;

constexpr unsigned int CAHitQuadrupletGenerator::minLayers;

CAHitQuadrupletGenerator::CAHitQuadrupletGenerator(const edm::ParameterSet& cfg, edm::ConsumesCollector& iC) :
extraHitRPhitolerance(cfg.getParameter<double>("extraHitRPhitolerance")), //extra window in ThirdHitPredictionFromCircle range (divide by R to get phi)
maxChi2(cfg.getParameter<edm::ParameterSet>("maxChi2")),
fitFastCircle(cfg.getParameter<bool>("fitFastCircle")),
fitFastCircleChi2Cut(cfg.getParameter<bool>("fitFastCircleChi2Cut")),
useBendingCorrection(cfg.getParameter<bool>("useBendingCorrection")),
caThetaCut(cfg.getParameter<double>("CAThetaCut")),
caPhiCut(cfg.getParameter<double>("CAPhiCut")),
caHardPtCut(cfg.getParameter<double>("CAHardPtCut"))
{
  edm::ParameterSet comparitorPSet = cfg.getParameter<edm::ParameterSet>("SeedComparitorPSet");
  std::string comparitorName = comparitorPSet.getParameter<std::string>("ComponentName");
  if (comparitorName != "none")
  {
    theComparitor.reset(SeedComparitorFactory::get()->create(comparitorName, comparitorPSet, iC));
  }
}

void CAHitQuadrupletGenerator::fillDescriptions(edm::ParameterSetDescription& desc) {
  desc.add<double>("extraHitRPhitolerance", 0.1);
  desc.add<bool>("fitFastCircle", false);
  desc.add<bool>("fitFastCircleChi2Cut", false);
  desc.add<bool>("useBendingCorrection", false);
  desc.add<double>("CAThetaCut", 0.00125);
  desc.add<double>("CAPhiCut", 10);
  desc.add<double>("CAHardPtCut", 0);
  desc.addOptional<bool>("CAOnlyOneLastHitPerLayerFilter")->setComment("Deprecated and has no effect. To be fully removed later when the parameter is no longer used in HLT configurations.");
  edm::ParameterSetDescription descMaxChi2;
  descMaxChi2.add<double>("pt1", 0.2);
  descMaxChi2.add<double>("pt2", 1.5);
  descMaxChi2.add<double>("value1", 500);
  descMaxChi2.add<double>("value2", 50);
  descMaxChi2.add<bool>("enabled", true);
  desc.add<edm::ParameterSetDescription>("maxChi2", descMaxChi2);

  edm::ParameterSetDescription descComparitor;
  descComparitor.add<std::string>("ComponentName", "none");
  descComparitor.setAllowAnything(); // until we have moved SeedComparitor too to EDProducers
  desc.add<edm::ParameterSetDescription>("SeedComparitorPSet", descComparitor);
}

void CAHitQuadrupletGenerator::initEvent(const edm::Event& ev, const edm::EventSetup& es) {
  if (theComparitor) theComparitor->init(ev, es);
}
namespace {
  void createGraphStructure(const SeedingLayerSetsHits& layers, CAGraph& g) {
    for (unsigned int i = 0; i < layers.size(); i++)
    {
        for (unsigned int j = 0; j < 4; ++j)
        {
            auto vertexIndex = 0;
            auto foundVertex = std::find(g.theLayers.begin(), g.theLayers.end(),
                    layers[i][j].name());
            if (foundVertex == g.theLayers.end())
            {
                g.theLayers.emplace_back(layers[i][j].name(), layers[i][j].hits().size());
                vertexIndex = g.theLayers.size() - 1;
            }
            else
            {
                vertexIndex = foundVertex - g.theLayers.begin();
            }
            if (j == 0)
            {

                if (std::find(g.theRootLayers.begin(), g.theRootLayers.end(),
                        vertexIndex) == g.theRootLayers.end())
                {
                    g.theRootLayers.emplace_back(vertexIndex);

                }

            }
        }
    }
  }
  void clearGraphStructure(const SeedingLayerSetsHits& layers, CAGraph& g) {
    g.theLayerPairs.clear();
    for (unsigned int i = 0; i < g.theLayers.size(); i++ ){
        g.theLayers[i].theInnerLayers.clear();
        g.theLayers[i].theInnerLayerPairs.clear();
        g.theLayers[i].theOuterLayers.clear();
        g.theLayers[i].theOuterLayerPairs.clear();
        for (auto & v : g.theLayers[i].isOuterHitOfCell) v.clear();
    }

  }
  void fillGraph(const SeedingLayerSetsHits& layers, const IntermediateHitDoublets::RegionLayerSets& regionLayerPairs,
                 CAGraph& g, std::vector<const HitDoublets *>& hitDoublets) {
    for (unsigned int i = 0; i < layers.size(); i++)
    {
        for (unsigned int j = 0; j < 4; ++j)
        {
            auto vertexIndex = 0;
            auto foundVertex = std::find(g.theLayers.begin(), g.theLayers.end(),
                    layers[i][j].name());
            if (foundVertex == g.theLayers.end())
            {
                vertexIndex = g.theLayers.size() - 1;
            }
            else
            {
                vertexIndex = foundVertex - g.theLayers.begin();
            }
    
            
            if (j > 0)
            {

                auto innerVertex = std::find(g.theLayers.begin(),
                        g.theLayers.end(), layers[i][j - 1].name());

                CALayerPair tmpInnerLayerPair(innerVertex - g.theLayers.begin(),
                        vertexIndex);

                if (std::find(g.theLayerPairs.begin(), g.theLayerPairs.end(),
                        tmpInnerLayerPair) == g.theLayerPairs.end())
                {
                    auto found = std::find_if(regionLayerPairs.begin(), regionLayerPairs.end(), [&](const IntermediateHitDoublets::LayerPairHitDoublets& pair) {
                      return pair.innerLayerIndex() == layers[i][j - 1].index() && pair.outerLayerIndex() == layers[i][j].index();
                    });
                                        if(found != regionLayerPairs.end()) {
                                          hitDoublets.emplace_back(&(found->doublets()));
                                          g.theLayerPairs.push_back(tmpInnerLayerPair);
                                          g.theLayers[vertexIndex].theInnerLayers.push_back(
                            innerVertex - g.theLayers.begin());
                                          innerVertex->theOuterLayers.push_back(vertexIndex);
                                          g.theLayers[vertexIndex].theInnerLayerPairs.push_back(
                            g.theLayerPairs.size() - 1);
                                          innerVertex->theOuterLayerPairs.push_back(
                            g.theLayerPairs.size() - 1);
                                        }
                }

            }

        }
    }
  }
}


void CAHitQuadrupletGenerator::hitNtuplets(const IntermediateHitDoublets& regionDoublets,
                                              std::vector<OrderedHitSeeds>& result,
                                              const edm::EventSetup& es,
                                              const SeedingLayerSetsHits& layers) {
  CAGraph g;

  std::vector<const HitDoublets *> hitDoublets;

  const int numberOfHitsInNtuplet = 4;
  std::vector<CACell::CAntuplet> foundQuadruplets;



 int index =0;
 for(const auto& regionLayerPairs: regionDoublets) {

     const TrackingRegion& region = regionLayerPairs.region();
     hitDoublets.clear();
     foundQuadruplets.clear();
      if (index == 0){   
        createGraphStructure(layers, g);
      }
      else{  
        clearGraphStructure(layers, g);
      }

      fillGraph(layers, regionLayerPairs, g, hitDoublets);

    CellularAutomaton ca(g);

    ca.createAndConnectCells(hitDoublets, region, caThetaCut,
            caPhiCut, caHardPtCut);

    ca.evolve(numberOfHitsInNtuplet);

    ca.findNtuplets(foundQuadruplets, numberOfHitsInNtuplet);

    auto & allCells = ca.getAllCells();
    
    const QuantityDependsPtEval maxChi2Eval = maxChi2.evaluator(es);

    // re-used thoughout
    std::array<float, 4> bc_r;
    std::array<float, 4> bc_z;
    std::array<float, 4> bc_errZ2;
    std::array<GlobalPoint, 4> gps;
    std::array<GlobalError, 4> ges;
    std::array<bool, 4> barrels;

    unsigned int numberOfFoundQuadruplets = foundQuadruplets.size();

    // Loop over quadruplets
    for (unsigned int quadId = 0; quadId < numberOfFoundQuadruplets; ++quadId)
    {

            auto isBarrel = [](const unsigned id) -> bool
            {
                return id == PixelSubdetector::PixelBarrel;
            };
            for(unsigned int i = 0; i< 3; ++i)
            {
                auto const& ahit = allCells[foundQuadruplets[quadId][i]].getInnerHit();
                gps[i] = ahit->globalPosition();
                ges[i] = ahit->globalPositionError();
                barrels[i] = isBarrel(ahit->geographicalId().subdetId());
            }

            auto const& ahit = allCells[foundQuadruplets[quadId][2]].getOuterHit();
            gps[3] = ahit->globalPosition();
            ges[3] = ahit->globalPositionError();
            barrels[3] = isBarrel(ahit->geographicalId().subdetId());
            // TODO:
            // - if we decide to always do the circle fit for 4 hits, we don't
            //   need ThirdHitPredictionFromCircle for the curvature; then we
            //   could remove extraHitRPhitolerance configuration parameter
            ThirdHitPredictionFromCircle predictionRPhi(gps[0], gps[2], extraHitRPhitolerance);
            const float curvature = predictionRPhi.curvature(ThirdHitPredictionFromCircle::Vector2D(gps[1].x(), gps[1].y()));
            const float abscurv = std::abs(curvature);
            const float thisMaxChi2 = maxChi2Eval.value(abscurv);
            if (theComparitor)
            {
                SeedingHitSet tmpTriplet(allCells[foundQuadruplets[quadId][0]].getInnerHit(),
                         allCells[foundQuadruplets[quadId][2]].getInnerHit(),
                         allCells[foundQuadruplets[quadId][2]].getOuterHit());


                if (!theComparitor->compatible(tmpTriplet) )
                {
                    continue;
                }
            }

            float chi2 = std::numeric_limits<float>::quiet_NaN();
            // TODO: Do we have any use case to not use bending correction?
            if (useBendingCorrection)
        {
                // Following PixelFitterByConformalMappingAndLine
                const float simpleCot = ( gps.back().z() - gps.front().z() ) / (gps.back().perp() - gps.front().perp() );
                const float pt = 1.f / PixelRecoUtilities::inversePt(abscurv, es);
                for (int i=0; i < 4; ++i)
                {
                    const GlobalPoint & point = gps[i];
                    const GlobalError & error = ges[i];
                    bc_r[i] = sqrt( sqr(point.x() - region.origin().x()) + sqr(point.y() - region.origin().y()) );
                    bc_r[i] += pixelrecoutilities::LongitudinalBendingCorrection(pt, es)(bc_r[i]);
                    bc_z[i] = point.z() - region.origin().z();
                    bc_errZ2[i] =  (barrels[i]) ? error.czz() : error.rerr(point)*sqr(simpleCot);
                }
                RZLine rzLine(bc_r, bc_z, bc_errZ2, RZLine::ErrZ2_tag());
                chi2 = rzLine.chi2();
            }
        else
            {
                RZLine rzLine(gps, ges, barrels);
                chi2 = rzLine.chi2();
            }
            if (edm::isNotFinite(chi2) || chi2 > thisMaxChi2)
            {
                continue;
            }
            // TODO: Do we have any use case to not use circle fit? Maybe
            // HLT where low-pT inefficiency is not a problem?
            if (fitFastCircle)
            {
                FastCircleFit c(gps, ges);
                chi2 += c.chi2();
                if (edm::isNotFinite(chi2)) continue;
                if (fitFastCircleChi2Cut && chi2 > thisMaxChi2) continue;
            }
        result[index].emplace_back(allCells[foundQuadruplets[quadId][0]].getInnerHit(),
                       allCells[foundQuadruplets[quadId][1]].getInnerHit(),
                       allCells[foundQuadruplets[quadId][2]].getInnerHit(),
                       allCells[foundQuadruplets[quadId][2]].getOuterHit());
        }
    index++;
     }

}