added PrimaryVertices factory (subCollection of CentralTrackVertices) (…

…#1609)

### Briefly, what does this PR introduce?


### What kind of change does this PR introduce?
- [ ] Bug fix (issue #__)
- [X] New feature (issue #__)
- [ ] Documentation update
- [ ] Other: __

### Please check if this PR fulfills the following:
- [ ] Tests for the changes have been added
- [ ] Documentation has been added / updated
- [ ] Changes have been communicated to collaborators

### Does this PR introduce breaking changes? What changes might users
need to make to their code?

### Does this PR change default behavior?

---------

Co-authored-by: Xin Dong <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Xin Dong <[email protected]>
Co-authored-by: Dmitry Kalinkin <[email protected]>

src/algorithms/reco/PrimaryVertices.cc

@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// Copyright (C) 2024 Daniel Brandenburg, Xin Dong
+
+#include <edm4eic/ReconstructedParticle.h>
+#include <edm4eic/VertexCollection.h>
+#include <edm4eic/unit_system.h>
+#include <edm4hep/Vector4f.h>
+#include <fmt/core.h>
+#include <podio/RelationRange.h>
+#include <cmath>
+#include <functional>
+#include <gsl/pointers>
+#include <map>
+
+#include "algorithms/reco/PrimaryVertices.h"
+#include "algorithms/reco/PrimaryVerticesConfig.h"
+
+namespace eicrecon {
+
+  /**
+   * @brief Initialize the PrimaryVertices Algorithm
+   *
+   */
+  void PrimaryVertices::init() {
+  }
+
+  /**
+   * @brief Produce a list of primary vertex candidates
+   *
+   * @param rcvtx  - input collection of all vertex candidates
+   * @return edm4eic::VertexCollection
+   */
+  void PrimaryVertices::process(const PrimaryVertices::Input& input,
+                const PrimaryVertices::Output& output) const {
+    const auto [rcvtx] = input;
+    auto [out_primary_vertices] = output;
+
+    // this multimap will store intermediate results
+    // so that we can sort them before filling output
+    // collection
+    std::multimap<int, edm4eic::Vertex, std::greater<int>> primaryVertexMap;
+
+    // our output collection of primary vertex
+    // ordered by N_trk = associatedParticle array size
+    out_primary_vertices->setSubsetCollection();
+
+    trace("We have {} candidate vertices", rcvtx->size());
+
+    for (const auto& vtx: *rcvtx) {
+      const auto &v = vtx.getPosition();
+
+      // some basic vertex selection
+      if (sqrt( v.x*v.x + v.y*v.y ) / edm4eic::unit::mm > m_cfg.maxVr ||
+          fabs( v.z ) / edm4eic::unit::mm > m_cfg.maxVz )
+        continue;
+
+      if (vtx.getChi2() > m_cfg.maxChi2) continue;
+
+      int N_trk = vtx.getAssociatedParticles().size();
+      trace( "\t N_trk = {}", N_trk );
+      primaryVertexMap.insert({N_trk, vtx});
+    } // vertex loop
+
+    bool first = true;
+    // map defined with std::greater<> will be iterated in descending order by the key
+    for (auto [N_trk, vertex] : primaryVertexMap) {
+      // Do not save primary candidates that
+      // are not within range
+      if ( N_trk > m_cfg.maxNtrk
+        || N_trk < m_cfg.minNtrk ){
+        continue;
+      }
+
+      // For logging and development
+      // report the highest N_trk candidate chosen
+      if (first) {
+        trace("Max N_trk Candidate:");
+        trace("\t N_trk = {}", N_trk);
+        trace("\t Primary vertex has xyz=( {}, {}, {} )", vertex.getPosition().x, vertex.getPosition().y, vertex.getPosition().z);
+        first = false;
+      }
+      out_primary_vertices->push_back(vertex);
+    } // loop on primaryVertexMap
+  }
+} // namespace eicrecon

src/algorithms/reco/PrimaryVertices.h

@@ -0,0 +1,38 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// Copyright (C) 2024 Daniel Brandenburg, Xin Dong
+
+#pragma once
+
+#include <algorithms/algorithm.h>
+#include <edm4eic/VertexCollection.h>
+#include <string>                                 // for basic_string
+#include <string_view>                            // for string_view
+
+#include "algorithms/interfaces/WithPodConfig.h"
+#include "algorithms/reco/PrimaryVerticesConfig.h"
+
+
+namespace eicrecon {
+
+using PrimaryVerticesAlgorithm = algorithms::Algorithm<
+   algorithms::Input<edm4eic::VertexCollection>,
+   algorithms::Output<edm4eic::VertexCollection>>;
+
+    class PrimaryVertices :
+       public PrimaryVerticesAlgorithm,
+       public WithPodConfig<PrimaryVerticesConfig>{
+
+       public:
+         PrimaryVertices(std::string_view name)
+              : PrimaryVerticesAlgorithm{name,
+                             {"inputVertices"},
+                             {"outputPrimaryVertices"},
+                             "Sort reconstructed vertices in PrimaryVertices collection"} {}
+
+         void init() final;
+         void process(const Input&, const Output&) const final;
+
+    private:
+
+    };
+} // namespace eicrecon

src/algorithms/reco/PrimaryVerticesConfig.h

@@ -0,0 +1,23 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// Copyright (C) 2024 Xin Dong
+
+#pragma once
+
+#include <string>
+#include <DD4hep/DD4hepUnits.h>
+
+namespace eicrecon {
+
+  struct PrimaryVerticesConfig {
+
+    // For now these are wide open
+    // In the future the cut should depend
+    // on the generator settings
+    float maxVr = 50.0; // mm
+    float maxVz = 500.0; // mm
+    float maxChi2 = 10000.0; //
+    int   minNtrk = 1;  // >=
+    int   maxNtrk = 1000000; // <=
+  };
+
+}  // end eicrecon namespace

src/global/reco/PrimaryVertices_factory.h

@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// Copyright (C) 2024 Xin Dong
+
+#pragma once
+
+#include <JANA/JEvent.h>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "algorithms/reco/PrimaryVertices.h"
+#include "algorithms/reco/PrimaryVerticesConfig.h"
+#include "services/algorithms_init/AlgorithmsInit_service.h"
+#include "extensions/jana/JOmniFactory.h"
+
+namespace eicrecon {
+
+class PrimaryVertices_factory :
+        public JOmniFactory<PrimaryVertices_factory, PrimaryVerticesConfig> {
+
+public:
+    using AlgoT = eicrecon::PrimaryVertices;
+private:
+    std::unique_ptr<AlgoT> m_algo;
+
+    PodioInput<edm4eic::Vertex> m_rc_vertices_input {this};
+
+    // Declare outputs
+    PodioOutput<edm4eic::Vertex> m_primary_vertices_output {this};
+
+    Service<AlgorithmsInit_service> m_algorithmsInit {this};
+
+public:
+    void Configure() {
+        m_algo = std::make_unique<AlgoT>(GetPrefix());
+        m_algo->level((algorithms::LogLevel)logger()->level());
+
+        m_algo->applyConfig(config());
+        m_algo->init();
+    }
+
+    void ChangeRun(int64_t run_number) {
+    }
+
+    void Process(int64_t run_number, uint64_t event_number) {
+        m_algo->process({m_rc_vertices_input()}, {m_primary_vertices_output().get()});
+    }
+};
+
+} // eicrecon

src/global/reco/reco.cc

@@ -11,6 +11,7 @@
 #include <edm4eic/MCRecoParticleAssociation.h>
 #include <edm4eic/ReconstructedParticle.h>
 #include <edm4hep/MCParticle.h>
+#include <fmt/core.h>
 #include <map>
 #include <memory>
 
@@ -44,6 +45,7 @@
 #include "global/reco/ChargedReconstructedParticleSelector_factory.h"
 #include "global/reco/MC2SmearedParticle_factory.h"
 #include "global/reco/MatchClusters_factory.h"
+#include "global/reco/PrimaryVertices_factory.h"
 #include "global/reco/ReconstructedElectrons_factory.h"
 #include "global/reco/ScatteredElectronsEMinusPz_factory.h"
 #include "global/reco/ScatteredElectronsTruth_factory.h"
@@ -384,6 +386,19 @@ void InitPlugin(JApplication *app) {
             app
     ));
 
+    app->Add(new JOmniFactoryGeneratorT<PrimaryVertices_factory>(
+        "PrimaryVertices",
+        {
+          "CentralTrackVertices"
+        },
+        {
+          "PrimaryVertices"
+        },
+        {
+        },
+        app
+    ));
+
 
 }
 } // extern "C"

src/services/io/podio/JEventProcessorPODIO.cc

@@ -221,6 +221,7 @@ JEventProcessorPODIO::JEventProcessorPODIO() {
             "ReconstructedElectrons",
             "ScatteredElectronsTruth",
             "ScatteredElectronsEMinusPz",
+            "PrimaryVertices",
 #if EDM4EIC_VERSION_MAJOR >= 6
             "HadronicFinalState",
 #endif