Add the utility codes for the MFT-MUON matching

Detectors/ITSMFT/MFT/CMakeLists.txt

@@ -18,5 +18,6 @@ add_subdirectory(calibration)
 add_subdirectory(condition)
 add_subdirectory(assessment)
 add_subdirectory(alignment)
+add_subdirectory(matching)
 
 o2_data_file(COPY data DESTINATION Detectors/Geometry/MFT/)

Detectors/ITSMFT/MFT/matching/CMakeLists.txt

@@ -0,0 +1,22 @@
+# Copyright 2019-2020 CERN and copyright holders of ALICE O2.
+# See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
+# All rights not expressly granted are reserved.
+#
+# This software is distributed under the terms of the GNU General Public
+# License v3 (GPL Version 3), copied verbatim in the file "COPYING".
+#
+# In applying this license CERN does not waive the privileges and immunities
+# granted to it by virtue of its status as an Intergovernmental Organization
+# or submit itself to any jurisdiction.
+
+o2_add_library(MFTMuonMatching
+    SOURCES src/MftMuonMatchingUtils.cxx
+            src/MatchingTagAndProbe.cxx
+    PUBLIC_LINK_LIBRARIES O2::CCDB
+                          O2::DataFormatsMFT
+                          O2::DetectorsCalibration
+                          O2::DetectorsDCS
+			  O2::GlobalTracking
+			  O2::ReconstructionDataFormats
+                          O2::DataFormatsGlobalTracking
+                          Microsoft.GSL::GSL)

Detectors/ITSMFT/MFT/matching/README.md

@@ -0,0 +1,4 @@
+<!-- doxy
+\page refMFTMuonMatching Matching
+/doxy -->
+# MFT Matching

Detectors/ITSMFT/MFT/matching/include/MFTMuonMatching/MatchingTagAndProbe.h

@@ -0,0 +1,166 @@
+// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
+// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
+// All rights not expressly granted are reserved.
+//
+// This software is distributed under the terms of the GNU General Public
+// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
+//
+// In applying this license CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+
+/// @file   MatchingTagAndProbe.h
+
+#ifndef O2_MFT_MATCHING_TAG_AND_PROBE_H
+#define O2_MFT_MATCHING_TAG_AND_PROBE_H
+
+/// @file   MatchingTagAndProbe.h
+/// @brief  Template-based utility for finding Tag and Probe pairs in ALICE O2.
+
+#include <cmath>
+
+#include "Math/SMatrix.h"
+#include "Math/SVector.h"
+
+#include "TLorentzVector.h"
+
+#include "Framework/Logger.h"
+#include "DetectorsBase/Propagator.h"
+#include "MCHTracking/TrackExtrap.h"
+#include "ReconstructionDataFormats/GlobalFwdTrack.h"
+#include "GlobalTracking/MatchGlobalFwd.h"
+
+namespace o2
+{
+namespace mft
+{
+
+using SMatrix55 = ROOT::Math::SMatrix<double, 5, 5, ROOT::Math::MatRepSym<double, 5>>;
+using SMatrix5 = ROOT::Math::SVector<Double_t, 5>;
+
+template <typename MUON, typename Collision>
+class MatchingTagAndProbe
+{
+ private:
+  inline void fillCovarianceArray(MUON const& muontrack, float cov[15]) const
+  {
+    cov[0] = muontrack.cXX();
+    cov[1] = muontrack.cXY();
+    cov[2] = muontrack.cYY();
+    cov[3] = muontrack.cPhiX();
+    cov[4] = muontrack.cPhiY();
+    cov[5] = muontrack.cPhiPhi();
+    cov[6] = muontrack.cTglX();
+    cov[7] = muontrack.cTglY();
+    cov[8] = muontrack.cTglPhi();
+    cov[9] = muontrack.cTglTgl();
+    cov[10] = muontrack.c1PtX();
+    cov[11] = muontrack.c1PtY();
+    cov[12] = muontrack.c1PtPhi();
+    cov[13] = muontrack.c1PtTgl();
+    cov[14] = muontrack.c1Pt21Pt2();
+  }
+
+  inline void setTagAndProbe()
+  {
+    if (muontrack1.pt() > muontrack2.pt()) {
+      tagIdx = 0;
+      probeIdx = 1;
+    } else {
+      tagIdx = 1;
+      probeIdx = 0;
+    }
+  }
+
+  o2::dataformats::GlobalFwdTrack muontrack_at_pv[2];
+  TLorentzVector mDimuon;
+  MUON muontrack1;
+  MUON muontrack2;
+  Collision collision;
+  int tagIdx, probeIdx;
+  int16_t mQ;
+
+  const float mMu = 0.105658; // Muon mass (GeV/c^2)
+
+  inline o2::dataformats::GlobalFwdTrack propagateMUONtoPV(MUON const& muontrack) const
+  {
+    const double mz = muontrack.z();
+    const double mchi2 = muontrack.chi2();
+    const float mx = muontrack.x();
+    const float my = muontrack.y();
+    const float mphi = muontrack.phi();
+    const float mtgl = muontrack.tgl();
+    const float m1pt = muontrack.signed1Pt();
+
+    float cov[15];
+
+    fillCovarianceArray(muontrack, cov);
+
+    SMatrix5 tpars(mx, my, mphi, mtgl, m1pt);
+    SMatrix55 tcovs(cov, cov + 15);
+
+    o2::track::TrackParCovFwd parcovmuontrack{mz, tpars, tcovs, mchi2};
+
+    o2::dataformats::GlobalFwdTrack gtrack;
+    gtrack.setParameters(tpars);
+    gtrack.setZ(parcovmuontrack.getZ());
+    gtrack.setCovariances(tcovs);
+
+    o2::globaltracking::MatchGlobalFwd mMatching;
+    auto mchtrack = mMatching.FwdtoMCH(gtrack);
+
+    o2::mch::TrackExtrap::extrapToVertex(mchtrack,
+                                         collision.posX(),
+                                         collision.posY(),
+                                         collision.posZ(),
+                                         collision.covXX(),
+                                         collision.covYY());
+
+    auto fwdtrack = mMatching.MCHtoFwd(mchtrack);
+    o2::dataformats::GlobalFwdTrack extrap_muontrack;
+    extrap_muontrack.setParameters(fwdtrack.getParameters());
+    extrap_muontrack.setZ(fwdtrack.getZ());
+    extrap_muontrack.setCovariances(fwdtrack.getCovariances());
+
+    return extrap_muontrack;
+  }
+
+ public:
+  MatchingTagAndProbe(const MUON& muon1, const MUON& muon2, const Collision& coll) : muontrack1(muon1), muontrack2(muon2), collision(coll), tagIdx(-1), probeIdx(-1), mQ(0)
+  {
+    mQ = muontrack1.sign() + muontrack2.sign();
+    setTagAndProbe();
+  }
+
+  inline void calcMuonPairAtPV()
+  {
+    muontrack_at_pv[0] = propagateMUONtoPV(muontrack1);
+    muontrack_at_pv[1] = propagateMUONtoPV(muontrack2);
+    TLorentzVector vMuon1, vMuon2;
+    vMuon1.SetPtEtaPhiM(muontrack_at_pv[0].getPt(),
+                        muontrack_at_pv[0].getEta(),
+                        muontrack_at_pv[0].getPhi(),
+                        mMu);
+    vMuon2.SetPtEtaPhiM(muontrack_at_pv[1].getPt(),
+                        muontrack_at_pv[1].getEta(),
+                        muontrack_at_pv[1].getPhi(),
+                        mMu);
+    mDimuon = vMuon1 + vMuon2;
+  }
+
+  inline int getTagMuonIndex() const { return tagIdx; }
+  inline int getProbeMuonIndex() const { return probeIdx; }
+  inline float getMass() const { return mDimuon.M(); }
+  inline float getPt() const { return mDimuon.Pt(); }
+  inline float getRap() const { return mDimuon.Rapidity(); }
+  inline int16_t getCharge() const { return mQ; }
+  inline const o2::dataformats::GlobalFwdTrack& getMuonAtPV(int idx) const
+  {
+    return muontrack_at_pv[idx];
+  }
+}; // end of class MatchingTagAndProbe
+
+} // namespace mft
+} // namespace o2
+
+#endif // O2_MFT_MATCHING_TAG_AND_PROBE_H