support index-based selection

README.md

@@ -77,3 +77,9 @@ To apply formatting to a file:
 ```
 clang-format -i -style=file /path/to/file.cpp
 ```
+Note that this will reformat the entire file.
+If you are preparing a PR, you can instead use 
+```
+ git clang-format  --style=file $(git merge-base upstream/master HEAD)
+```
+to only format the lines you changed (avoids bloating your PR - unless you wish to clean up the whole file 😉). 

analyzers/dataframe/FCCAnalyses/MCParticle.h

@@ -3,8 +3,10 @@
 #define  MCPARTICLE_ANALYZERS_H
 
 #include <cmath>
+#include <functional>
 #include <vector>
 
+#include "FCCAnalyses/Utils.h"
 #include "ROOT/RVec.hxx"
 #include "TLorentzVector.h"
 #include "edm4hep/MCParticleData.h"
@@ -30,26 +32,32 @@ namespace MCParticle{
     bool  operator() (ROOT::VecOps::RVec<edm4hep::MCParticleData> in);
   };
 
+  /// Template implementation for basic selection function on MC particle data.
+  using MCParticleSelection = Utils::selByPredicate<edm4hep::MCParticleData>;
+
   /// select MCParticles with transverse momentum greater than a minimum value [GeV]
-  struct sel_pt {
+  struct sel_pt : MCParticleSelection {
     sel_pt(float arg_min_pt);
-    float m_min_pt = 20; //> transverse momentum threshold [GeV]
-    ROOT::VecOps::RVec<edm4hep::MCParticleData>  operator() (ROOT::VecOps::RVec<edm4hep::MCParticleData> in);
+  };
+
+  /// select MCParticles with absolute pseudorapidity less than a max value
+  struct sel_eta : MCParticleSelection {
+    sel_eta(float arg_max_eta);
   };
 
   /// select MCParticles with their status
-  struct sel_genStatus {
+  struct sel_genStatus : MCParticleSelection {
     sel_genStatus(int arg_status);
-    int m_status = 1; //> Generator status
-    ROOT::VecOps::RVec<edm4hep::MCParticleData>  operator() (ROOT::VecOps::RVec<edm4hep::MCParticleData> in);
   };
 
   /// select MCParticles with their PDG id
-  struct sel_pdgID {
+  struct sel_pdgID : MCParticleSelection {
     sel_pdgID(int arg_pdg, bool arg_chargeconjugate);
-    int m_pdg = 13;
-    bool m_chargeconjugate = true;
-    ROOT::VecOps::RVec<edm4hep::MCParticleData>  operator() (ROOT::VecOps::RVec<edm4hep::MCParticleData> in);
+  };
+
+  /// select MCParticles with a non-zero charge
+  struct sel_charged : MCParticleSelection {
+    sel_charged();
   };
 
   /// get MC history tree for a given MCParticle index
@@ -116,7 +124,6 @@ namespace MCParticle{
                                         			     ROOT::VecOps::RVec<edm4hep::MCParticleData> in ,
 								     ROOT::VecOps::RVec<int> ind);
 
-
   /// return the parent index of a given list of MC particles
   ROOT::VecOps::RVec<int> get_parentid(ROOT::VecOps::RVec<int> mcind, ROOT::VecOps::RVec<edm4hep::MCParticleData> mc, ROOT::VecOps::RVec<int> parents);
 
@@ -210,6 +217,16 @@ namespace MCParticle{
   /// return the list of stable particles from the decay of a mother particle, looking at the full decay chain recursively. i is the mother index in the Particle block
   std::vector<int> get_list_of_stable_particles_from_decay( int i, ROOT::VecOps::RVec<edm4hep::MCParticleData> in, ROOT::VecOps::RVec<int> ind) ;
 
+  /// return the list of stable particles from the decays of a mother particle,
+  /// looking at the full decay chain recursively. i is the list of mother
+  /// indices to process in the Particle block. Will return a vector of vectors
+  /// - each vector is the set of children for one of the mothers in the input
+  /// vector
+  ROOT::VecOps::RVec<ROOT::VecOps::RVec<int>>
+  get_lists_of_stable_particles_from_decays(
+      ROOT::VecOps::RVec<int> i, ROOT::VecOps::RVec<edm4hep::MCParticleData> in,
+      ROOT::VecOps::RVec<int> ind);
+
   /// return the list of particles from the decay of a mother particle. i is the mother index in the Particle block.
   std::vector<int> get_list_of_particles_from_decay( int i,
 						 ROOT::VecOps::RVec<edm4hep::MCParticleData> in,

analyzers/dataframe/FCCAnalyses/ReconstructedParticle2MC.h

@@ -125,12 +125,44 @@ namespace ReconstructedParticle2MC{
 									 ROOT::VecOps::RVec<edm4hep::ReconstructedParticleData> reco,
 									 ROOT::VecOps::RVec<edm4hep::MCParticleData> mc) ;
 
-  /// select ReconstructedParticles matched to the (stable) MC particles whose indices are passed in a list
-  ROOT::VecOps::RVec<edm4hep::ReconstructedParticleData> selRP_matched_to_list( ROOT::VecOps::RVec<int>   mcParticles_indices,
-										ROOT::VecOps::RVec<int> recind,
-										ROOT::VecOps::RVec<int> mcind,
-										ROOT::VecOps::RVec<edm4hep::ReconstructedParticleData> reco,
-										ROOT::VecOps::RVec<edm4hep::MCParticleData> mc) ;
+  /// select ReconstructedParticles matched to the MC particles whose indices
+  /// are passed in a list
+  /// @param mcParticles_indices indices of the MC particles to look up
+  /// @param recind: reco index component of the MCRecoAssociations
+  /// @param mcind: mc index component of the MCRecoAssociations
+  /// @param reco: full reco particle list (ReconstructedParticles)
+  /// @param mc: full mc particle list (Particles)
+  /// @param require_stable: if set to true, will only match stable particles.
+  /// @return List of ReconstructedParticle candidates with length corresponding
+  /// to the number of *stable* MC particles in the mcParticles_indices vector.
+  /// In presence of unstable particles, no 1:1 correspondence. For
+  /// non-reconstructed stable MC particles, a dummy particle will be inserted.
+  /// If 1:1 length correspondence is required, set require_stable to false.
+  ROOT::VecOps::RVec<edm4hep::ReconstructedParticleData> selRP_matched_to_list(
+      const ROOT::VecOps::RVec<int> &mcParticles_indices,
+      const ROOT::VecOps::RVec<int> &recind,
+      const ROOT::VecOps::RVec<int> &mcind,
+      const ROOT::VecOps::RVec<edm4hep::ReconstructedParticleData> &reco,
+      const ROOT::VecOps::RVec<edm4hep::MCParticleData> &mc,
+      bool require_stable = true);
+  /// select indices of ReconstructedParticles matched to the MC particles whose
+  /// indices are passed in a list
+  /// @param mcParticles_indices indices of the MC particles to look up
+  /// @param recind: reco index component of the MCRecoAssociations
+  /// @param mcind: mc index component of the MCRecoAssociations
+  /// @param mc: full mc particle list (Particles)
+  /// @param require_stable: if set to true, will only match stable particles.
+  /// @return List of ReconstructedParticle candidates with length corresponding
+  /// to the number of *stable* MC particles in the mcParticles_indices vector.
+  /// In presence of unstable particles, no 1:1 correspondence. For
+  /// non-reconstructed stable MC particles, a "-1" entry will be inserted. If
+  /// 1:1 length correspondence is required, set require_stable to false.
+  ROOT::VecOps::RVec<int> selRP_indices_matched_to_list(
+      const ROOT::VecOps::RVec<int> &mcParticles_indices,
+      const ROOT::VecOps::RVec<int> &recind,
+      const ROOT::VecOps::RVec<int> &mcind,
+      const ROOT::VecOps::RVec<edm4hep::MCParticleData> &mc,
+      bool require_stable = true);
 
   /// return the index of the MC particle that is associated to a given track (via the track-reco association)
   int getTrack2MC_index (  int track_index,