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;
}