[PWGJE,EMCAL-689] Add DeltaEta and DeltaPhi values to EMCALMatchedTracks table

- Add DeltaEta and DeltaPhi values to `EMCALMatchedTracks` table
- Add PWGJE/Core/utilsTrackMatchingEMC.h where we do simple track matching. Previously we used the jetutils which matched tracks to clusters and clusters to track both. To save time we now use our own utils header and do only one. Also to make the code more easily understandble added struct `MatchResult` instead of using a complex tuple of vector<vector> abomination.
- Fix PWGJE/Tasks/emcTmMonitor.cxx O2linter warnings and includes

Author: mhemmer-cern

PWGJE/Core/CMakeLists.txt

@@ -25,5 +25,6 @@ o2physics_target_root_dictionary(PWGJECore
                       JetBkgSubUtils.h
                       JetDerivedDataUtilities.h
                       emcalCrossTalkEmulation.h
+                      utilsTrackMatchingEMC.h
               LINKDEF PWGJECoreLinkDef.h)
 endif()

PWGJE/Core/JetUtilities.h

@@ -76,11 +76,6 @@ std::tuple<std::vector<std::vector<int>>, std::vector<std::vector<int>>> MatchCl
     throw std::invalid_argument("track collection eta and phi sizes don't match. Check the inputs.");
   }
 
-  // for (std::size_t iTrack = 0; iTrack < nTracks; iTrack++) {
-  //   if (trackEta[iTrack] == 0)
-  //     LOG(warning) << "Track eta is 0!";
-  // }
-
   // Build the KD-trees using vectors
   // We build two trees:
   // treeBase, which contains the base collection.

PWGJE/Core/utilsTrackMatchingEMC.h

@@ -0,0 +1,119 @@
+// 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 utilsTrackMatchingEMC.h
+/// \brief EMCal track matching related utils
+/// \author Marvin Hemmer <marvin.hemmer@cern.ch>
+
+#ifndef PWGJE_CORE_UTILSTRACKMATCHINGEMC_H_
+#define PWGJE_CORE_UTILSTRACKMATCHINGEMC_H_
+
+#include <TKDTree.h>
+
+#include <algorithm>
+#include <cmath>
+#include <cstddef>
+#include <limits>
+#include <span>
+#include <stdexcept>
+#include <vector>
+
+namespace tmemcutilities
+{
+
+struct MatchResult {
+  std::vector<std::vector<int>> matchIndexTrack;
+  std::vector<std::vector<float>> matchDeltaPhi;
+  std::vector<std::vector<float>> matchDeltaEta;
+};
+
+/**
+ * Match clusters and tracks.
+ *
+ * Match cluster with tracks, where maxNumberMatches are considered in dR=maxMatchingDistance.
+ * If no unique match was found for a jet, an index of -1 is stored.
+ * The same map is created for clusters matched to tracks e.g. for electron analyses.
+ *
+ * @param clusterPhi cluster collection phi.
+ * @param clusterEta cluster collection eta.
+ * @param trackPhi track collection phi.
+ * @param trackEta track collection eta.
+ * @param maxMatchingDistance Maximum matching distance.
+ * @param maxNumberMatches Maximum number of matches (e.g. 5 closest).
+ *
+ * @returns (cluster to track index map, track to cluster index map)
+ */
+MatchResult matchTracksToCluster(
+  std::span<float> clusterPhi,
+  std::span<float> clusterEta,
+  std::span<float> trackPhi,
+  std::span<float> trackEta,
+  double maxMatchingDistance,
+  int maxNumberMatches)
+{
+  const std::size_t nClusters = clusterEta.size();
+  const std::size_t nTracks = trackEta.size();
+  MatchResult result;
+
+  result.matchIndexTrack.resize(nClusters);
+  result.matchDeltaPhi.resize(nClusters);
+  result.matchDeltaEta.resize(nClusters);
+
+  if (nClusters == 0 || nTracks == 0) {
+    // There are no jets, so nothing to be done.
+    return result;
+  }
+  // Input sizes must match
+  if (clusterPhi.size() != clusterEta.size()) {
+    throw std::invalid_argument("cluster collection eta and phi sizes don't match. Check the inputs.");
+  }
+  if (trackPhi.size() != trackEta.size()) {
+    throw std::invalid_argument("track collection eta and phi sizes don't match. Check the inputs.");
+  }
+
+  // Build the KD-trees using vectors
+  // We build two trees:
+  // treeBase, which contains the base collection.
+  // treeTag, which contains the tag collection.
+  // The trees are built to match in two dimensions (eta, phi)
+  TKDTree<int, float> treeTrack(trackEta.size(), 2, 1);
+  treeTrack.SetData(0, trackEta.data());
+  treeTrack.SetData(1, trackPhi.data());
+  treeTrack.Build();
+
+  // Find the track closest to each cluster.
+  for (std::size_t iCluster = 0; iCluster < nClusters; iCluster++) {
+    float point[2] = {clusterEta[iCluster], clusterPhi[iCluster]};
+    int index[50];      // size 50 for safety
+    float distance[50]; // size 50 for safery
+    std::fill_n(index, 50, -1);
+    std::fill_n(distance, 50, std::numeric_limits<float>::max());
+    treeTrack.FindNearestNeighbors(point, maxNumberMatches, index, distance);
+
+    // allocate enough memory
+    result.matchIndexTrack[iCluster].reserve(maxNumberMatches);
+    result.matchDeltaPhi[iCluster].reserve(maxNumberMatches);
+    result.matchDeltaEta[iCluster].reserve(maxNumberMatches);
+
+    // test whether indices are matching:
+    for (int m = 0; m < maxNumberMatches; m++) {
+      if (index[m] >= 0 && distance[m] < maxMatchingDistance) {
+        result.matchIndexTrack[iCluster].push_back(index[m]);
+        result.matchDeltaPhi[iCluster].push_back(trackPhi[index[m]] - clusterPhi[iCluster]);
+        result.matchDeltaEta[iCluster].push_back(trackEta[index[m]] - clusterEta[iCluster]);
+      }
+    }
+  }
+  return result;
+}
+}; // namespace tmemcutilities
+
+#endif // PWGJE_CORE_UTILSTRACKMATCHINGEMC_H_

PWGJE/DataModel/EMCALClusters.h

@@ -162,10 +162,13 @@ using EMCALClusterCell = EMCALClusterCells::iterator;
 using EMCALAmbiguousClusterCell = EMCALAmbiguousClusterCells::iterator;
 namespace emcalmatchedtrack
 {
-DECLARE_SOA_INDEX_COLUMN(Track, track); //! linked to Track table only for tracks that were matched
+DECLARE_SOA_INDEX_COLUMN(Track, track);        //! linked to Track table only for tracks that were matched
+DECLARE_SOA_COLUMN(DeltaPhi, deltaPhi, float); //! difference between matched track and cluster azimuthal angle
+DECLARE_SOA_COLUMN(DeltaEta, deltaEta, float); //! difference between matched track and cluster pseudorapidity
 } // namespace emcalmatchedtrack
-DECLARE_SOA_TABLE(EMCALMatchedTracks, "AOD", "EMCMATCHTRACKS",                                     //!
-                  o2::soa::Index<>, emcalclustercell::EMCALClusterId, emcalmatchedtrack::TrackId); //!
+DECLARE_SOA_TABLE(EMCALMatchedTracks, "AOD", "EMCMATCHTRACKS", //!
+                  o2::soa::Index<>, emcalclustercell::EMCALClusterId, emcalmatchedtrack::TrackId,
+                  emcalmatchedtrack::DeltaPhi, emcalmatchedtrack::DeltaEta); //!
 using EMCALMatchedTrack = EMCALMatchedTracks::iterator;
 } // namespace o2::aod
 #endif // PWGJE_DATAMODEL_EMCALCLUSTERS_H_