refactor: Move MLAmbiguitySolver to Core

CI/physmon/phys_perf_mon.sh

@@ -265,6 +265,15 @@ function trackfinding() {
             $path/performance_finding_ckf_ambi.html \
             $path/performance_finding_ckf_ambi
     fi
+
+    if [ -f $refdir/$path/performance_finding_ckf_ml_solver.root ]; then
+        run_histcmp \
+            $outdir/data/$path/performance_finding_ckf_ml_solver.root \
+            $refdir/$path/performance_finding_ckf_ml_solver.root \
+            "ML Ambisolver | ${name}" \
+            $path/performance_finding_ckf_ml_solver.html \
+            $path/performance_finding_ckf_ml_solver
+    fi
 }
 
 function vertexing() {

CI/physmon/workflows/physmon_trackfinding_ttbar_pu200.py

@@ -19,7 +19,9 @@
     CkfConfig,
     addCKFTracks,
     addAmbiguityResolution,
+    addAmbiguityResolutionML,
     AmbiguityResolutionConfig,
+    AmbiguityResolutionMLConfig,
     addVertexFitting,
     VertexFinder,
     TrackSelectorConfig,
@@ -134,13 +136,25 @@
         outputDirRoot=tp,
     )
 
+    addAmbiguityResolutionML(
+        s,
+        AmbiguityResolutionMLConfig(
+            maximumSharedHits=3, maximumIterations=1000000, nMeasurementsMin=6
+        ),
+        tracks="ckf_tracks",
+        outputDirRoot=tp,
+        onnxModelFile=Path(__file__).resolve().parent.parent.parent.parent
+        / "thirdparty/OpenDataDetector/data/duplicateClassifier.onnx",
+    )
+
     addAmbiguityResolution(
         s,
         AmbiguityResolutionConfig(
             maximumSharedHits=3,
             maximumIterations=100000,
             nMeasurementsMin=6,
         ),
+        tracks="ckf_tracks",
         outputDirRoot=tp,
     )
 
@@ -187,6 +201,17 @@
         tp / "performance_fitting_ambi.root",
         tp / "performance_fitting_ckf_ambi.root",
     )
+
+    shutil.move(
+        tp / "performance_finding_ambiML.root",
+        tp / "performance_finding_ckf_ml_solver.root",
+    )
+
+    shutil.move(
+        tp / "performance_fitting_ambiML.root",
+        tp / "performance_fitting_ckf_ml_solver.root",
+    )
+
     for vertexing in ["amvf_gauss_notime", "amvf_grid_time"]:
         shutil.move(
             tp / f"{vertexing}/performance_vertexing.root",
@@ -200,6 +225,8 @@
         "performance_fitting_ckf.root",
         "performance_finding_ckf_ambi.root",
         "performance_fitting_ckf_ambi.root",
+        "performance_finding_ckf_ml_solver.root",
+        "performance_fitting_ckf_ml_solver.root",
         "performance_vertexing_amvf_gauss_notime.root",
         "performance_vertexing_amvf_grid_time.root",
     ]:

Core/include/Acts/AmbiguityResolution/AmbiguityNetworkConcept.hpp

@@ -0,0 +1,51 @@
+// This file is part of the ACTS project.
+//
+// Copyright (C) 2016 CERN for the benefit of the ACTS project
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+#pragma once
+
+#include "Acts/EventData/TrackContainer.hpp"
+#include "Acts/EventData/TrackContainerFrontendConcept.hpp"
+#include "Acts/EventData/VectorMultiTrajectory.hpp"
+#include "Acts/EventData/VectorTrackContainer.hpp"
+#include "Acts/Utilities/Concepts.hpp"
+
+namespace Acts {
+
+/// @brief Concept for the ambiguity network used in the ambiguity resolution
+///
+/// The ambiguity network correspond to the AmbiguityTrackClassifier found in
+/// the Onnx plugin. It is used to score the tracks and select the best ones.
+///
+/// The constructor of the Ambiguity Solver network should take string as input
+/// corresponding to the path of the ONNX model.
+/// The implementation of the Ambiguity Solver network should have two methods:
+/// - inferScores: takes clusters (a list of track ID associated with a cluster
+/// ID) and the track container and return an outputTensor (list of scores for
+///                each track in the clusters).
+/// - trackSelection: Takes clusters and the output tensor from the inferScores
+///                   method and return the list of track ID to keep.
+///
+/// @tparam N the type of the network
+template <typename network_t>
+concept AmbiguityNetworkConcept = requires(
+    TrackContainer<VectorTrackContainer, VectorMultiTrajectory,
+                   detail::ValueHolder> &tracks,
+    std::unordered_map<std::size_t, std::vector<std::size_t>> &clusters,
+    std::vector<std::vector<float>> &outputTensor, const char *modelPath,
+    network_t &n) {
+  { network_t(modelPath) } -> std::same_as<network_t>;
+
+  {
+    n.inferScores(clusters, tracks)
+  } -> std::same_as<std::vector<std::vector<float>>>;
+  {
+    n.trackSelection(clusters, outputTensor)
+  } -> std::same_as<std::vector<std::size_t>>;
+};
+
+}  // namespace Acts

Core/include/Acts/AmbiguityResolution/AmbiguityResolutionML.hpp

@@ -0,0 +1,136 @@
+// This file is part of the ACTS project.
+//
+// Copyright (C) 2016 CERN for the benefit of the ACTS project
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+#pragma once
+
+#include "Acts/AmbiguityResolution/AmbiguityNetworkConcept.hpp"
+#include "Acts/Definitions/Units.hpp"
+#include "Acts/EventData/TrackContainer.hpp"
+#include "Acts/Utilities/Delegate.hpp"
+#include "Acts/Utilities/Logger.hpp"
+
+#include <cstddef>
+#include <map>
+#include <memory>
+#include <string>
+#include <tuple>
+#include <vector>
+
+namespace Acts {
+
+/// Generic implementation of the machine learning ambiguity resolution
+/// Contains method for data preparations
+template <AmbiguityNetworkConcept AmbiguityNetwork>
+class AmbiguityResolutionML {
+ public:
+  struct Config {
+    /// Path to the model file for the duplicate neural network
+    std::string inputDuplicateNN = "";
+    /// Minimum number of measurement to form a track.
+    std::size_t nMeasurementsMin = 7;
+  };
+  /// Construct the ambiguity resolution algorithm.
+  ///
+  /// @param cfg is the algorithm configuration
+  /// @param logger is the logging instance
+  AmbiguityResolutionML(const Config& cfg,
+                        std::unique_ptr<const Logger> logger = getDefaultLogger(
+                            "AmbiguityResolutionML", Logging::INFO))
+      : m_cfg{cfg},
+        m_duplicateClassifier(m_cfg.inputDuplicateNN.c_str()),
+        m_logger{std::move(logger)} {}
+
+  /// Associate the hits to the tracks
+  ///
+  /// This algorithm performs the mapping of hits ID to track ID. Our final goal
+  /// is too loop over all the tracks (and their associated hits) by order of
+  /// decreasing number hits for this we use a multimap where the key is the
+  /// number of hits as this will automatically perform the sorting.
+  ///
+  /// @param tracks is the input track container
+  /// @param sourceLinkHash is the hash function for the source link, will be used to associate to tracks
+  /// @param sourceLinkEquality is the equality function for the source link used used to associated hits to tracks
+  /// @return an ordered list containing pairs of track ID and associated measurement ID
+  template <TrackContainerFrontend track_container_t,
+            typename source_link_hash_t, typename source_link_equality_t>
+  std::multimap<int, std::pair<std::size_t, std::vector<std::size_t>>>
+  mapTrackHits(const track_container_t& tracks,
+               const source_link_hash_t& sourceLinkHash,
+               const source_link_equality_t& sourceLinkEquality) const {
+    // A map to store (and generate) the measurement index for each source link
+    auto measurementIndexMap =
+        std::unordered_map<SourceLink, std::size_t, source_link_hash_t,
+                           source_link_equality_t>(0, sourceLinkHash,
+                                                   sourceLinkEquality);
+
+    // A map to store the track Id and their associated measurements ID, a
+    // multimap is used to automatically sort the tracks by the number of
+    // measurements
+    std::multimap<int, std::pair<std::size_t, std::vector<std::size_t>>>
+        trackMap;
+    std::size_t trackIndex = 0;
+    std::vector<std::size_t> measurements;
+    // Loop over all the trajectories in the events
+    for (const auto& track : tracks) {
+      // Kick out tracks that do not fulfill our initial requirements
+      if (track.nMeasurements() < m_cfg.nMeasurementsMin) {
+        continue;
+      }
+      measurements.clear();
+      for (auto ts : track.trackStatesReversed()) {
+        if (ts.typeFlags().test(Acts::TrackStateFlag::MeasurementFlag)) {
+          SourceLink sourceLink = ts.getUncalibratedSourceLink();
+          // assign a new measurement index if the source link was not seen yet
+          auto emplace = measurementIndexMap.try_emplace(
+              sourceLink, measurementIndexMap.size());
+          measurements.push_back(emplace.first->second);
+        }
+      }
+      trackMap.emplace(track.nMeasurements(),
+                       std::make_pair(trackIndex, measurements));
+      ++trackIndex;
+    }
+    return trackMap;
+  }
+
+  /// Select the track associated with each cluster
+  ///
+  /// In this algorithm the call the neural network to score the tracks and then
+  /// select the track with the highest score in each cluster
+  ///
+  /// @param clusters is a map of clusters, each cluster correspond to a vector of track ID
+  /// @param tracks is the input track container
+  /// @return a vector of trackID corresponding tho the good tracks
+  template <TrackContainerFrontend track_container_t>
+  std::vector<std::size_t> solveAmbiguity(
+      std::unordered_map<std::size_t, std::vector<std::size_t>>& clusters,
+      const track_container_t& tracks) const {
+    std::vector<std::vector<float>> outputTensor =
+        m_duplicateClassifier.inferScores(clusters, tracks);
+    std::vector<std::size_t> goodTracks =
+        m_duplicateClassifier.trackSelection(clusters, outputTensor);
+
+    return goodTracks;
+  }
+
+ private:
+  // Configuration
+  Config m_cfg;
+
+  // The neural network for duplicate classification, the network
+  // implementation is chosen with the AmbiguityNetwork template parameter
+  AmbiguityNetwork m_duplicateClassifier;
+
+  /// Logging instance
+  std::unique_ptr<const Logger> m_logger = nullptr;
+
+  /// Private access to logging instance
+  const Logger& logger() const { return *m_logger; }
+};
+
+}  // namespace Acts

Core/include/Acts/TrackFinding/detail/AmbiguityTrackClustering.hpp

@@ -15,7 +15,15 @@
 
 namespace Acts::detail {
 
-/// Clusterise tracks based on shared hits
+/// Cluster tracks based on shared hits.
+///
+/// In this algorithm we will loop through all the tracks by decreasing number
+/// of measurements. Cluster are created when a new track is encountered that
+/// doesn't share hits with the leading track of a previous cluster (with the
+/// leading track defined as the track that lead to the cluster creation). If a
+/// track shares hits with the leading track of a cluster, it is added to that
+/// cluster. If a track shares hits with multiple clusters, it is associated to
+/// the cluster with the leading track with the most hits.
 ///
 /// @param trackMap : Multimap storing pair of track ID and vector of measurement ID. The keys are the number of measurement and are just there to facilitate the ordering.
 /// @return an unordered map representing the clusters, the keys the ID of the primary track of each cluster and the store a vector of track IDs.

Core/src/TrackFinding/AmbiguityTrackClustering.cpp

@@ -21,8 +21,9 @@ Acts::detail::clusterDuplicateTracks(
   // different clusters.
   std::unordered_map<std::size_t, std::size_t> hitToTrack;
 
-  // Loop over all the tracks
-  for (const auto& [_, trackValue] : trackMap) {
+  // Loop backward over all the tracks
+  for (auto track = trackMap.rbegin(); track != trackMap.rend(); ++track) {
+    const auto& trackValue = track->second;
     std::vector<std::size_t> hits = trackValue.second;
     auto matchedTrack = hitToTrack.end();
     // Loop over all the hits in the track

Examples/Algorithms/TrackFindingML/CMakeLists.txt

@@ -1,7 +1,5 @@
 set(SOURCES
-    src/AmbiguityResolutionML.cpp
     src/AmbiguityResolutionMLAlgorithm.cpp
-    src/AmbiguityResolutionMLDBScanAlgorithm.cpp
     src/SeedFilterMLAlgorithm.cpp
 )