FIND_DECAY and FIND_MCDECAY functor

Create two functor named FIND_DECAY and FIND_MC_DECAY that implements respectively the algorithms DecayFinder (new, see !3091 (merged)) and MCDecayFinder.

To be used in composition with other functors to get information about particles belonging to the decay chain.

FIND_DECAY (FIND_MC_DECAY) is MAP of _FIND_DECAY (_FIND_MC_DECAY), functor accepting const LHCb::Particle* (const LHCb::MCParticle*) or const LHCb::Particle& (const LHCb::MCParticle&) and returning a const LHCb::Particle* (const LHCb::MCParticle*).

TODO:

• Fix test;
• Adapt the functor to support MCParticles.

Perhaps related to issue: #356

Example in the DV MR DaVinci!781 (merged)

cc: @amathad

Phys/FunctorCore/tests/src/InstantiateFunctors.cpp

@@ -235,8 +235,7 @@ using dls_2 = std::invoke_result_t<Functors::Composite::ComputeDecayLengthSignif
 using dls_3 = std::invoke_result_t<Functors::Composite::ComputeDecayLengthSignificance,
                                    LHCb::Event::PV::PrimaryVertex const&, soa_composite>;
 
-auto chi2perdof_func =
-    Functors::chain( FF::ValueOr{0.}, FT::Chi2PerDoF{}, Functors::Particle::GetTrack{} );
+auto chi2perdof_func      = Functors::chain( FF::ValueOr{0.}, FT::Chi2PerDoF{}, Functors::Particle::GetTrack{} );
 using chi2perdof_prepared = decltype( chi2perdof_func.prepare( EventContext{}, Functors::TopLevelInfo{} ) );
 using chi2perdof_1        = std::invoke_result_t<chi2perdof_prepared, bool, LHCb::Particle const&>;
 using chi2perdof_2        = std::invoke_result_t<chi2perdof_prepared, bool, LHCb::Particle const*>;
@@ -245,8 +244,7 @@ using chi2perdof_3 = std::invoke_result_t<chi2perdof_prepared, bool, LHCb::Parti
 using chi2perdof_4 = std::invoke_result_t<chi2perdof_prepared, bool, charged_basic>;
 using chi2perdof_5 = std::invoke_result_t<chi2perdof_prepared, bool, soa_composite>;
 
-auto chi2_func =
-    Functors::chain( FF::ValueOr{0.}, FT::Chi2{}, Functors::Particle::GetTrack{} );
+auto chi2_func      = Functors::chain( FF::ValueOr{0.}, FT::Chi2{}, Functors::Particle::GetTrack{} );
 using chi2_prepared = decltype( chi2_func.prepare( EventContext{}, Functors::TopLevelInfo{} ) );
 using chi2_1        = std::invoke_result_t<chi2_prepared, bool, LHCb::Particle const&>;
 using chi2_2        = std::invoke_result_t<chi2_prepared, bool, LHCb::Particle const*>;
@@ -262,21 +260,18 @@ auto allpv_fd_func =
     // bind map and TES functors with forwarding the arguments
     Functors::bind(
         FF::Map( /* The functor to map over a range. */
-                                   // chain magnitude and flight distance functor
-                                   Functors::chain(
-                                       // get magnitude of the flight distance vector
-                                       FC::Magnitude{},
-                                       // subtract the vertex position from the particle position
-                                       operator-(
-                                           // vertex position: LHCb::Vertex -> Gaudi::XYZPoint -> Vec3
-                                           // Arg1: LHCb::Vertex
-                                           Functors::chain( FC::ToLinAlg{}, FC::Position{},
-                                                            FC::EndVertex{},
-                                                            FC::ForwardArgs<1>() ),
-                                           // end vertex of particle: LHCb::Particle -> Gaudi::XYZPoint -> Vec3
-                                           // Arg0: LHCb::Particle
-                                           Functors::chain( FC::ToLinAlg{}, FC::Position{},
-                                                            FC::ForwardArgs<0>() ) ) ) ),
+                 // chain magnitude and flight distance functor
+                 Functors::chain(
+                     // get magnitude of the flight distance vector
+                     FC::Magnitude{},
+                     // subtract the vertex position from the particle position
+                     operator-(
+                         // vertex position: LHCb::Vertex -> Gaudi::XYZPoint -> Vec3
+                         // Arg1: LHCb::Vertex
+                         Functors::chain( FC::ToLinAlg{}, FC::Position{}, FC::EndVertex{}, FC::ForwardArgs<1>() ),
+                         // end vertex of particle: LHCb::Particle -> Gaudi::XYZPoint -> Vec3
+                         // Arg0: LHCb::Particle
+                         Functors::chain( FC::ToLinAlg{}, FC::Position{}, FC::ForwardArgs<0>() ) ) ) ),
         // get TES object and forward it
         FC::TES<LHCb::Event::PV::PrimaryVertexContainer>(
             /* List of DataHandles */ std::vector{std::string{"FakeLocation"}} ),
@@ -292,15 +287,14 @@ using allpv_fd_func_result_type = std::invoke_result_t<allpv_fd_func_type, bool,
 // Test for ALLPV_IP
 //
 // create an instance of ALLPV IP functor (obtained from functor.code() in python)
-auto allpv_ip_func = Functors::bind(
-    FF::Map( FC::ImpactParameter{} ),
-    Functors::chain(
-        // vertex position: LHCb::Vertex -> Gaudi::XYZPoint -> Vec3
-        FF::Map( Functors::chain( FC::ToLinAlg{}, FC::Position{} ) ),
-        // get TES object and forward it
-        FC::TES<LHCb::Event::PV::PrimaryVertexContainer>(
-            /* List of DataHandles */ std::vector{std::string{"FakeLocation"}} ) ),
-    FC::ForwardArgs<>{} );
+auto allpv_ip_func = Functors::bind( FF::Map( FC::ImpactParameter{} ),
+                                     Functors::chain(
+                                         // vertex position: LHCb::Vertex -> Gaudi::XYZPoint -> Vec3
+                                         FF::Map( Functors::chain( FC::ToLinAlg{}, FC::Position{} ) ),
+                                         // get TES object and forward it
+                                         FC::TES<LHCb::Event::PV::PrimaryVertexContainer>(
+                                             /* List of DataHandles */ std::vector{std::string{"FakeLocation"}} ) ),
+                                     FC::ForwardArgs<>{} );
 // get the type of the prepared functor that is returned when calling prepare() on the above functor
 using allpv_ip_func_type = decltype( allpv_ip_func.prepare( EventContext{}, Functors::TopLevelInfo{} ) );
 // get the result_type of invoking the allpv_ip_func_type with inputs.
@@ -312,24 +306,22 @@ using allpv_ip_func_result_type = std::invoke_result_t<allpv_ip_func_type, bool,
 auto asym_func = operator/(
     operator-(
         Functors::chain( ::FC::Rho_Coordinate{}, ::FT::ThreeMomentum{} ),
-        Functors::chain(
-            ::FF::ValueOr( /* The default value. */ 0.0f ), ::FF::Sum{},
-            ::FF::Map( /* The functor to map over a range. */ Functors::chain(
-                ::FC::Rho_Coordinate{}, ::FT::ThreeMomentum{}, ::FC::To{} ) ),
-            Functors::bind( ::FC::Relations{},
-                            ::FC::TES<LHCb::Relation1D<LHCb::Particle, LHCb::Particle>>(
-                                /* List of DataHandles */ std::vector{std::string{"FakeLocation"}} ),
-                            ::FC::ForwardArgs<>() ) ) ),
+        Functors::chain( ::FF::ValueOr( /* The default value. */ 0.0f ), ::FF::Sum{},
+                         ::FF::Map( /* The functor to map over a range. */ Functors::chain(
+                             ::FC::Rho_Coordinate{}, ::FT::ThreeMomentum{}, ::FC::To{} ) ),
+                         Functors::bind( ::FC::Relations{},
+                                         ::FC::TES<LHCb::Relation1D<LHCb::Particle, LHCb::Particle>>(
+                                             /* List of DataHandles */ std::vector{std::string{"FakeLocation"}} ),
+                                         ::FC::ForwardArgs<>() ) ) ),
     operator+(
         Functors::chain( ::FC::Rho_Coordinate{}, ::FT::ThreeMomentum{} ),
-        Functors::chain(
-            ::FF::ValueOr( /* The default value. */ 0.0f ), ::FF::Sum{},
-            ::FF::Map( /* The functor to map over a range. */ Functors::chain(
-                ::FC::Rho_Coordinate{}, ::FT::ThreeMomentum{}, ::FC::To{} ) ),
-            Functors::bind( ::FC::Relations{},
-                            ::FC::TES<LHCb::Relation1D<LHCb::Particle, LHCb::Particle>>(
-                                /* List of DataHandles */ std::vector{std::string{"FakeLocation"}} ),
-                            ::FC::ForwardArgs<>() ) ) ) );
+        Functors::chain( ::FF::ValueOr( /* The default value. */ 0.0f ), ::FF::Sum{},
+                         ::FF::Map( /* The functor to map over a range. */ Functors::chain(
+                             ::FC::Rho_Coordinate{}, ::FT::ThreeMomentum{}, ::FC::To{} ) ),
+                         Functors::bind( ::FC::Relations{},
+                                         ::FC::TES<LHCb::Relation1D<LHCb::Particle, LHCb::Particle>>(
+                                             /* List of DataHandles */ std::vector{std::string{"FakeLocation"}} ),
+                                         ::FC::ForwardArgs<>() ) ) ) );
 using asym_func_type        = decltype( asym_func.prepare( EventContext{}, Functors::TopLevelInfo{} ) );
 using asym_func_result_type = std::invoke_result_t<asym_func_type, bool, LHCb::Particle const&>;
 
@@ -344,19 +336,24 @@ using npvs_func_res_type = std::invoke_result_t<npvs_func_type, bool, LHCb::RecS
 using inmuon_1           = std::invoke_result_t<FT::InAcceptance, LHCb::Particle const&>;
 
 // Create an instance for FIND_DECAY functor
-using find_decay_func = Functors::chain( ::FF::ValueOr( /* The default value. */ std::integral_constant<int, 0>{} ), ::FC::Rho_Coordinate{}, ::FT::ThreeMomentum{}, ::FF::Front{}, ::Functors::Decay::FindDecay( /* Decay descriptor */ std::string{"[B0->K+ pi-]CC"} ), ::FC::TES<LHCb::Particle::ConstVector>( /* List of DataHandles */ std::vector{std::string{"FakeLocation"}}) );
-//get the type of the prepared functor
+using find_decay_func = Functors::chain(
+    ::FF::ValueOr( /* The default value. */ std::integral_constant<int, 0>{} ), ::FC::Rho_Coordinate{},
+    ::FT::ThreeMomentum{}, ::FF::Front{},
+    ::Functors::Decay::FindDecay( /* Decay descriptor */ std::string{"[B0->K+ pi-]CC"} ),
+    ::FC::TES<LHCb::Particle::ConstVector>( /* List of DataHandles */ std::vector{std::string{"FakeLocation"}} ) );
+// get the type of the prepared functor
 using find_decay_func_type = decltype( find_decay_func.prepare( EventContext{}, Functors::TopLevelInfo{} ) );
 // get the result_type of invoking the find_decay_func_type with inputs.
 // The bool needs to be there since it is a mask to be passed to prepared functor
 // Then the actual input is passed forwarding the arguments (LHCb::Particle const ref).
 using find_decay_func_result_type = std::invoke_result_t<find_decay_func_type, bool, LHCb::Particle const&>;
 // Check no.2: instead of using a dummy tes location, trying passing directly a std::vector<LHCb::Particle const&>
-using find_decay_func2 = Functors::chain( ::FF::ValueOr( /* The default value. */ std::integral_constant<int, 0>{} ), ::FC::Rho_Coordinate{}, ::FT::ThreeMomentum{}, ::FF::Front{}, ::Functors::Decay::FindDecay( /* Decay descriptor */ std::string{"[B0->K+ pi-]CC"} ) );
-using find_decay_func_type2 = decltype( find_decay_func2.prepare( EventContext{}, Functors::TopLevelInfo{} ) );
+using find_decay_func2 = Functors::chain( ::FF::ValueOr( /* The default value. */ std::integral_constant<int, 0>{} ),
+                                          ::FC::Rho_Coordinate{}, ::FT::ThreeMomentum{}, ::FF::Front{},
+                                          ::Functors::Decay::FindDecay( /* Decay descriptor */ std::string{
+                                              "[B0->K+ pi-]CC"} ) );
+using find_decay_func_type2        = decltype( find_decay_func2.prepare( EventContext{}, Functors::TopLevelInfo{} ) );
 using find_decay_func_result_type2 = std::invoke_result_t<find_decay_func_type2, bool, LHCb::Particle const&>;
- 
- 
 
 BOOST_AUTO_TEST_CASE( instantiate_all ) {
   // empty on purpose -- just need to compile and instantiate...