/data/refman/pasoursint/CMSSW_6_1_2_SLHC4_patch1/src/RecoBTag/SecondaryVertex/src/CombinedSVComputer.cc

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#include <iostream>
#include <cstddef>
#include <string>
#include <cmath>
#include <vector>

#include <Math/VectorUtil.h>

#include "FWCore/Utilities/interface/Exception.h"
#include "FWCore/ParameterSet/interface/ParameterSet.h"

#include "DataFormats/Math/interface/Vector3D.h"
#include "DataFormats/Math/interface/LorentzVector.h"
#include "DataFormats/GeometryCommonDetAlgo/interface/Measurement1D.h"
#include "DataFormats/GeometryVector/interface/GlobalPoint.h"
#include "DataFormats/GeometryVector/interface/GlobalVector.h"
#include "DataFormats/GeometryVector/interface/VectorUtil.h"
#include "DataFormats/TrackReco/interface/Track.h"
#include "DataFormats/TrackReco/interface/TrackFwd.h"
#include "DataFormats/BTauReco/interface/TrackIPTagInfo.h"
#include "DataFormats/BTauReco/interface/SecondaryVertexTagInfo.h"  
#include "DataFormats/BTauReco/interface/TaggingVariable.h"
#include "DataFormats/BTauReco/interface/VertexTypes.h"

#include "RecoVertex/VertexPrimitives/interface/ConvertToFromReco.h"

#include "RecoBTag/SecondaryVertex/interface/ParticleMasses.h"
#include "RecoBTag/SecondaryVertex/interface/TrackSorting.h"
#include "RecoBTag/SecondaryVertex/interface/TrackSelector.h"
#include "RecoBTag/SecondaryVertex/interface/TrackKinematics.h"
#include "RecoBTag/SecondaryVertex/interface/V0Filter.h"

#include "RecoBTag/SecondaryVertex/interface/CombinedSVComputer.h"

using namespace reco;

struct CombinedSVComputer::IterationRange {
        int begin, end, increment;
};

#define range_for(i, x) \
        for(int i = (x).begin; i != (x).end; i += (x).increment)

static edm::ParameterSet dropDeltaR(const edm::ParameterSet &pset)
{
        edm::ParameterSet psetCopy(pset);
        psetCopy.addParameter<double>("jetDeltaRMax", 99999.0);
        return psetCopy;
}

CombinedSVComputer::CombinedSVComputer(const edm::ParameterSet &params) :
        trackFlip(params.getParameter<bool>("trackFlip")),
        vertexFlip(params.getParameter<bool>("vertexFlip")),
        charmCut(params.getParameter<double>("charmCut")),
        sortCriterium(TrackSorting::getCriterium(params.getParameter<std::string>("trackSort"))),
        trackSelector(params.getParameter<edm::ParameterSet>("trackSelection")),
        trackNoDeltaRSelector(dropDeltaR(params.getParameter<edm::ParameterSet>("trackSelection"))),
        trackPseudoSelector(params.getParameter<edm::ParameterSet>("trackPseudoSelection")),
        pseudoMultiplicityMin(params.getParameter<unsigned int>("pseudoMultiplicityMin")),
        trackMultiplicityMin(params.getParameter<unsigned int>("trackMultiplicityMin")),
        minTrackWeight(params.getParameter<double>("minimumTrackWeight")),
        useTrackWeights(params.getParameter<bool>("useTrackWeights")),
        vertexMassCorrection(params.getParameter<bool>("correctVertexMass")),
        pseudoVertexV0Filter(params.getParameter<edm::ParameterSet>("pseudoVertexV0Filter")),
        trackPairV0Filter(params.getParameter<edm::ParameterSet>("trackPairV0Filter"))
{
}

inline double CombinedSVComputer::flipValue(double value, bool vertex) const
{
        return (vertex ? vertexFlip : trackFlip) ? -value : value;
}

inline CombinedSVComputer::IterationRange CombinedSVComputer::flipIterate(
                                                int size, bool vertex) const
{
        IterationRange range;
        if (vertex ? vertexFlip : trackFlip) {
                range.begin = size - 1;
                range.end = -1;
                range.increment = -1;
        } else {
                range.begin = 0;
                range.end = size;
                range.increment = +1;
        }

        return range;
}

const TrackIPTagInfo::TrackIPData &
CombinedSVComputer::threshTrack(const TrackIPTagInfo &trackIPTagInfo,
                                const TrackIPTagInfo::SortCriteria sort,
                                const reco::Jet &jet,
                                const GlobalPoint &pv) const
{
        const edm::RefVector<TrackCollection> &tracks =
                                        trackIPTagInfo.selectedTracks();
        const std::vector<TrackIPTagInfo::TrackIPData> &ipData =
                                        trackIPTagInfo.impactParameterData();
        std::vector<std::size_t> indices = trackIPTagInfo.sortedIndexes(sort);

        IterationRange range = flipIterate(indices.size(), false);
        TrackKinematics kin;
        range_for(i, range) {
                std::size_t idx = indices[i];
                const TrackIPTagInfo::TrackIPData &data = ipData[idx];
                const Track &track = *tracks[idx];

                if (!trackNoDeltaRSelector(track, data, jet, pv))
                        continue;

                kin.add(track);
                if (kin.vectorSum().M() > charmCut) 
                        return data;
        }

        static const TrackIPTagInfo::TrackIPData dummy = {
                GlobalPoint(),
                GlobalPoint(),
                Measurement1D(-1.0, 1.0),
                Measurement1D(-1.0, 1.0),
                Measurement1D(-1.0, 1.0),
                Measurement1D(-1.0, 1.0),
                0.
        };
        return dummy;
}

static double etaRel(const math::XYZVector &dir, const math::XYZVector &track)
{
        double momPar = dir.Dot(track);
        double energy = std::sqrt(track.Mag2() +
                                  ROOT::Math::Square(ParticleMasses::piPlus));

        return 0.5 * std::log((energy + momPar) / (energy - momPar));
}

TaggingVariableList
CombinedSVComputer::operator () (const TrackIPTagInfo &ipInfo,
                                 const SecondaryVertexTagInfo &svInfo) const
{
        using namespace ROOT::Math;

        edm::RefToBase<Jet> jet = ipInfo.jet();
        math::XYZVector jetDir = jet->momentum().Unit();
        bool havePv = ipInfo.primaryVertex().isNonnull();
        GlobalPoint pv;
        if (havePv)
                pv = GlobalPoint(ipInfo.primaryVertex()->x(),
                                 ipInfo.primaryVertex()->y(),
                                 ipInfo.primaryVertex()->z());

        btag::Vertices::VertexType vtxType = btag::Vertices::NoVertex;

        TaggingVariableList vars; // = ipInfo.taggingVariables();

        vars.insert(btau::jetPt, jet->pt(), true);
        vars.insert(btau::jetEta, jet->eta(), true);

        if (ipInfo.tracks().size() < trackMultiplicityMin)
                return vars;

        TrackKinematics allKinematics;
        TrackKinematics vertexKinematics;

        int vtx = -1;
        IterationRange range = flipIterate(svInfo.nVertices(), true);
        range_for(i, range) {
                if (vtx < 0)
                        vtx = i;

                const Vertex &vertex = svInfo.secondaryVertex(i);
                bool hasRefittedTracks = vertex.hasRefittedTracks();
                TrackRefVector tracks = svInfo.vertexTracks(i);
                for(TrackRefVector::const_iterator track = tracks.begin();
                    track != tracks.end(); track++) {
                        double w = svInfo.trackWeight(i, *track);
                        if (w < minTrackWeight)
                                continue;
                        if (hasRefittedTracks) {
                                Track actualTrack =
                                                vertex.refittedTrack(*track);
                                vertexKinematics.add(actualTrack, w);
                                vars.insert(btau::trackEtaRel, etaRel(jetDir,
                                                actualTrack.momentum()), true);
                        } else {
                                vertexKinematics.add(**track, w);
                                vars.insert(btau::trackEtaRel, etaRel(jetDir,
                                                (*track)->momentum()), true);
                        }
                }
        }

        if (vtx >= 0) {
                vtxType = btag::Vertices::RecoVertex;

                vars.insert(btau::flightDistance2dVal,
                            flipValue(
                                svInfo.flightDistance(vtx, true).value(),
                                true),
                            true);
                vars.insert(btau::flightDistance2dSig,
                            flipValue(
                                svInfo.flightDistance(vtx, true).significance(),
                                true),
                            true);
                vars.insert(btau::flightDistance3dVal,
                            flipValue(
                                svInfo.flightDistance(vtx, false).value(),
                                true),
                            true);
                vars.insert(btau::flightDistance3dSig,
                            flipValue(
                                svInfo.flightDistance(vtx, false).significance(),
                                true),
                            true);
                vars.insert(btau::vertexJetDeltaR,
                            Geom::deltaR(svInfo.flightDirection(vtx), jetDir),true);
                vars.insert(btau::jetNSecondaryVertices, svInfo.nVertices(), true);
                vars.insert(btau::vertexNTracks, svInfo.nVertexTracks(), true);
        }

        std::vector<std::size_t> indices = ipInfo.sortedIndexes(sortCriterium);
        const std::vector<TrackIPTagInfo::TrackIPData> &ipData =
                                                ipInfo.impactParameterData();
        const edm::RefVector<TrackCollection> &tracks =
                                                ipInfo.selectedTracks();
        std::vector<TrackRef> pseudoVertexTracks;

        TrackRef trackPairV0Test[2];
        range = flipIterate(indices.size(), false);
        range_for(i, range) {
                std::size_t idx = indices[i];
                const TrackIPTagInfo::TrackIPData &data = ipData[idx];
                const TrackRef &trackRef = tracks[idx];
                const Track &track = *trackRef;

                // filter track

                if (!trackSelector(track, data, *jet, pv))
                        continue;

                // add track to kinematics for all tracks in jet

                allKinematics.add(track);

                // if no vertex was reconstructed, attempt pseudo vertex

                if (vtxType == btag::Vertices::NoVertex &&
                    trackPseudoSelector(track, data, *jet, pv)) {
                        pseudoVertexTracks.push_back(trackRef);
                        vertexKinematics.add(track);
                }

                // check against all other tracks for V0 track pairs

                trackPairV0Test[0] = tracks[idx];
                bool ok = true;
                range_for(j, range) {
                        if (i == j)
                                continue;

                        std::size_t pairIdx = indices[j];
                        const TrackIPTagInfo::TrackIPData &pairTrackData =
                                                        ipData[pairIdx];
                        const TrackRef &pairTrackRef = tracks[pairIdx];
                        const Track &pairTrack = *pairTrackRef;

                        if (!trackSelector(pairTrack, pairTrackData, *jet, pv))
                                continue;

                        trackPairV0Test[1] = pairTrackRef;
                        if (!trackPairV0Filter(trackPairV0Test, 2)) {
                                ok = false;
                                break;
                        }
                }
                if (!ok)
                        continue;

                // add track variables

                math::XYZVector trackMom = track.momentum();
                double trackMag = std::sqrt(trackMom.Mag2());

                vars.insert(btau::trackSip3dVal,
                            flipValue(data.ip3d.value(), false), true);
                vars.insert(btau::trackSip3dSig,
                            flipValue(data.ip3d.significance(), false), true);
                vars.insert(btau::trackSip2dVal,
                            flipValue(data.ip2d.value(), false), true);
                vars.insert(btau::trackSip2dSig,
                            flipValue(data.ip2d.significance(), false), true);
                vars.insert(btau::trackJetDistVal, data.distanceToJetAxis.value(), true);
//              vars.insert(btau::trackJetDistSig, data.distanceToJetAxis.significance(), true);
//              vars.insert(btau::trackFirstTrackDist, data.distanceToFirstTrack, true);
//              vars.insert(btau::trackGhostTrackVal, data.distanceToGhostTrack.value(), true);
//              vars.insert(btau::trackGhostTrackSig, data.distanceToGhostTrack.significance(), true);
                vars.insert(btau::trackDecayLenVal, havePv ? (data.closestToJetAxis - pv).mag() : -1.0, true);

                vars.insert(btau::trackMomentum, trackMag, true);
                vars.insert(btau::trackEta, trackMom.Eta(), true);

                vars.insert(btau::trackPtRel, VectorUtil::Perp(trackMom, jetDir), true);
                vars.insert(btau::trackPPar, jetDir.Dot(trackMom), true);
                vars.insert(btau::trackDeltaR, VectorUtil::DeltaR(trackMom, jetDir), true);
                vars.insert(btau::trackPtRatio, VectorUtil::Perp(trackMom, jetDir) / trackMag, true);
                vars.insert(btau::trackPParRatio, jetDir.Dot(trackMom) / trackMag, true);
        } 

        if (vtxType == btag::Vertices::NoVertex &&
            vertexKinematics.numberOfTracks() >= pseudoMultiplicityMin &&
            pseudoVertexV0Filter(pseudoVertexTracks)) {
                vtxType = btag::Vertices::PseudoVertex;
                for(std::vector<TrackRef>::const_iterator track =
                                                pseudoVertexTracks.begin();
                    track != pseudoVertexTracks.end(); ++track)
                        vars.insert(btau::trackEtaRel, etaRel(jetDir,
                                                (*track)->momentum()), true);
        }

        vars.insert(btau::vertexCategory, vtxType, true);
        vars.insert(btau::trackSumJetDeltaR,
                    VectorUtil::DeltaR(allKinematics.vectorSum(), jetDir), true);
        vars.insert(btau::trackSumJetEtRatio,
                    allKinematics.vectorSum().Et() / ipInfo.jet()->et(), true);
        vars.insert(btau::trackSip3dSigAboveCharm,
                    flipValue(
                        threshTrack(ipInfo, TrackIPTagInfo::IP3DSig, *jet, pv)
                                                        .ip3d.significance(),
                        false),
                    true);
        vars.insert(btau::trackSip2dSigAboveCharm,
                    flipValue(
                        threshTrack(ipInfo, TrackIPTagInfo::IP2DSig, *jet, pv)
                                                        .ip2d.significance(),
                        false),
                    true);

        if (vtxType != btag::Vertices::NoVertex) {
                math::XYZTLorentzVector allSum = useTrackWeights
                        ? allKinematics.weightedVectorSum()
                        : allKinematics.vectorSum();
                math::XYZTLorentzVector vertexSum = useTrackWeights
                        ? vertexKinematics.weightedVectorSum()
                        : vertexKinematics.vectorSum();

                if (vtxType != btag::Vertices::RecoVertex) {
                        vars.insert(btau::vertexNTracks,
                                    vertexKinematics.numberOfTracks(), true);
                        vars.insert(btau::vertexJetDeltaR,
                                    VectorUtil::DeltaR(vertexSum, jetDir), true);
                }

                double vertexMass = vertexSum.M();
                if (vtxType == btag::Vertices::RecoVertex &&
                    vertexMassCorrection) {
                        GlobalVector dir = svInfo.flightDirection(vtx);
                        double vertexPt2 =
                                math::XYZVector(dir.x(), dir.y(), dir.z()).
                                        Cross(vertexSum).Mag2() / dir.mag2();
                        vertexMass = std::sqrt(vertexMass * vertexMass +
                                               vertexPt2) + std::sqrt(vertexPt2);
                }
                vars.insert(btau::vertexMass, vertexMass, true);
                if (allKinematics.numberOfTracks())
                        vars.insert(btau::vertexEnergyRatio,
                                    vertexSum.E() / allSum.E(), true);
                else
                        vars.insert(btau::vertexEnergyRatio, 1, true);
        }

        vars.finalize();

        return vars;
}