[ALICE3] TRK: allow ACTS clustering (#15174)

* [ALICE3] TRK: allow ACTS clustering

* Add ACTS clusterer

Author: njacazio

Detectors/Upgrades/ALICE3/TRK/reconstruction/CMakeLists.txt

@@ -9,10 +9,16 @@
 # granted to it by virtue of its status as an Intergovernmental Organization
 # or submit itself to any jurisdiction.
 
+if(Acts_FOUND)
+  set(actsTarget Acts::Core)
+endif()
+
 o2_add_library(TRKReconstruction
                TARGETVARNAME targetName
                SOURCES src/TimeFrame.cxx
                        src/Clusterer.cxx
+                       $<$<BOOL:${Acts_FOUND}>:src/ClustererACTS.cxx>
+                       $<$<BOOL:${Acts_FOUND}>:src/TrackerACTS.cxx>
                PUBLIC_LINK_LIBRARIES
                        O2::ITStracking
                        O2::GPUCommon
@@ -27,11 +33,23 @@ o2_add_library(TRKReconstruction
                        O2::DataFormatsITS
                        O2::TRKSimulation
                        nlohmann_json::nlohmann_json
+                       ${actsTarget}
                PRIVATE_LINK_LIBRARIES
                        O2::Steer
                        TBB::tbb)
 
+if(Acts_FOUND)
+  target_compile_definitions(${targetName} PUBLIC O2_WITH_ACTS)
+endif()
+
+set(dictHeaders include/TRKReconstruction/TimeFrame.h
+                include/TRKReconstruction/Clusterer.h)
+
+if(Acts_FOUND)
+  list(APPEND dictHeaders include/TRKReconstruction/ClustererACTS.h
+                          include/TRKReconstruction/TrackerACTS.h)
+endif()
+
 o2_target_root_dictionary(TRKReconstruction
-                          HEADERS include/TRKReconstruction/TimeFrame.h
-                                  include/TRKReconstruction/Clusterer.h
+                          HEADERS ${dictHeaders}
                           LINKDEF src/TRKReconstructionLinkDef.h)

Detectors/Upgrades/ALICE3/TRK/reconstruction/include/TRKReconstruction/Clusterer.h

@@ -161,17 +161,17 @@ class Clusterer
   };
   //----------------------------------------------
 
-  void process(gsl::span<const Digit> digits,
-               gsl::span<const DigROFRecord> digitROFs,
-               std::vector<o2::trk::Cluster>& clusters,
-               std::vector<unsigned char>& patterns,
-               std::vector<o2::trk::ROFRecord>& clusterROFs,
-               const ConstDigitTruth* digitLabels = nullptr,
-               ClusterTruth* clusterLabels = nullptr,
-               gsl::span<const DigMC2ROFRecord> digMC2ROFs = {},
-               std::vector<o2::trk::MC2ROFRecord>* clusterMC2ROFs = nullptr);
-
- private:
+  virtual void process(gsl::span<const Digit> digits,
+                       gsl::span<const DigROFRecord> digitROFs,
+                       std::vector<o2::trk::Cluster>& clusters,
+                       std::vector<unsigned char>& patterns,
+                       std::vector<o2::trk::ROFRecord>& clusterROFs,
+                       const ConstDigitTruth* digitLabels = nullptr,
+                       ClusterTruth* clusterLabels = nullptr,
+                       gsl::span<const DigMC2ROFRecord> digMC2ROFs = {},
+                       std::vector<o2::trk::MC2ROFRecord>* clusterMC2ROFs = nullptr);
+
+ protected:
   int mNHugeClus = 0;
   std::unique_ptr<ClustererThread> mThread;
   std::vector<int> mSortIdx; ///< reusable per-ROF sort buffer

Detectors/Upgrades/ALICE3/TRK/reconstruction/include/TRKReconstruction/ClustererACTS.h

@@ -0,0 +1,43 @@
+// Copyright 2019-2026 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 ClustererACTS.h
+/// \brief Definition of the TRK cluster finder
+
+#ifndef ALICEO2_TRK_CLUSTERERACTS_H
+#define ALICEO2_TRK_CLUSTERERACTS_H
+
+#include "TRKReconstruction/Clusterer.h"
+
+namespace o2::trk
+{
+
+class GeometryTGeo;
+
+class ClustererACTS : public Clusterer
+{
+ public:
+  void process(gsl::span<const Digit> digits,
+               gsl::span<const DigROFRecord> digitROFs,
+               std::vector<o2::trk::Cluster>& clusters,
+               std::vector<unsigned char>& patterns,
+               std::vector<o2::trk::ROFRecord>& clusterROFs,
+               const ConstDigitTruth* digitLabels = nullptr,
+               ClusterTruth* clusterLabels = nullptr,
+               gsl::span<const DigMC2ROFRecord> digMC2ROFs = {},
+               std::vector<o2::trk::MC2ROFRecord>* clusterMC2ROFs = nullptr) override;
+
+ private:
+};
+
+} // namespace o2::trk
+
+#endif