From 9854009505553d6df95ab71f332fe69e6193e755 Mon Sep 17 00:00:00 2001
From: Andreas Stefl <stefl.andreas@gmail.com>
Date: Wed, 28 Feb 2024 22:30:01 +0100
Subject: [PATCH] feat: Use `Barcode` for vertex ID in
 `VertexPerformanceWriter` (#2970)

Instead of decomposing the `Barcode` in primary and secondary we can set the other components to zero and use it as a vertex ID.

It would be handy to have an actual vertex ID and a truth vertex EDM but this is a story for another day.

blocked by
- https://github.com/acts-project/acts/pull/2989
---
 .../Performance/VertexPerformanceWriter.cpp   | 35 +++++++++----------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/Examples/Io/Performance/ActsExamples/Io/Performance/VertexPerformanceWriter.cpp b/Examples/Io/Performance/ActsExamples/Io/Performance/VertexPerformanceWriter.cpp
index ae179a88b0c..7ed676f31fc 100644
--- a/Examples/Io/Performance/ActsExamples/Io/Performance/VertexPerformanceWriter.cpp
+++ b/Examples/Io/Performance/ActsExamples/Io/Performance/VertexPerformanceWriter.cpp
@@ -19,6 +19,7 @@
 #include "Acts/Utilities/MultiIndex.hpp"
 #include "Acts/Utilities/UnitVectors.hpp"
 #include "Acts/Vertexing/TrackAtVertex.hpp"
+#include "ActsExamples/EventData/SimHit.hpp"
 #include "ActsExamples/EventData/SimParticle.hpp"
 #include "ActsExamples/EventData/Trajectories.hpp"
 #include "ActsExamples/Validation/TrackClassification.hpp"
@@ -396,7 +397,7 @@ ActsExamples::ProcessCode ActsExamples::VertexPerformanceWriter::writeT(
     // Containers for storing truth particles and truth vertices that contribute
     // to the reconstructed vertex
     SimParticleContainer particleAtVtx;
-    std::vector<int> contributingTruthVertices;
+    std::vector<SimBarcode> contributingTruthVertices;
 
     if (m_cfg.useTracks) {
       for (const auto& trk : tracksAtVtx) {
@@ -418,8 +419,9 @@ ActsExamples::ProcessCode ActsExamples::VertexPerformanceWriter::writeT(
             // the i-th track parameters
             const auto& particle = associatedTruthParticles[i];
             particleAtVtx.insert(particle);
-            int priVtxId = particle.particleId().vertexPrimary();
-            contributingTruthVertices.push_back(priVtxId);
+            SimBarcode vtxId =
+                particle.particleId().setParticle(0).setSubParticle(0);
+            contributingTruthVertices.push_back(vtxId);
             foundMatchingParams = true;
             break;
           }
@@ -430,18 +432,19 @@ ActsExamples::ProcessCode ActsExamples::VertexPerformanceWriter::writeT(
       }  // end loop tracksAtVtx
     } else {
       for (const auto& particle : allTruthParticles) {
-        int priVtxId = particle.particleId().vertexPrimary();
-        contributingTruthVertices.push_back(priVtxId);
+        SimBarcode vtxId =
+            particle.particleId().setParticle(0).setSubParticle(0);
+        contributingTruthVertices.push_back(vtxId);
       }
     }
 
     // Find true vertex that contributes most to the reconstructed vertex
-    std::map<int, int> fmap;
-    for (int priVtxId : contributingTruthVertices) {
-      fmap[priVtxId]++;
+    std::map<SimBarcode, int> fmap;
+    for (const SimBarcode& vtxId : contributingTruthVertices) {
+      fmap[vtxId]++;
     }
     int maxOccurrence = -1;
-    int maxOccurrenceId = -1;
+    SimBarcode maxOccurrenceId = -1;
     for (auto it : fmap) {
       if (it.second > maxOccurrence) {
         maxOccurrenceId = it.first;
@@ -452,8 +455,8 @@ ActsExamples::ProcessCode ActsExamples::VertexPerformanceWriter::writeT(
     // Count number of reconstructible tracks on truth vertex
     int nTracksOnTruthVertex = 0;
     for (const auto& particle : associatedTruthParticles) {
-      int priVtxId = particle.particleId().vertexPrimary();
-      if (priVtxId == maxOccurrenceId) {
+      SimBarcode vtxId = particle.particleId().setParticle(0).setSubParticle(0);
+      if (vtxId == maxOccurrenceId) {
         ++nTracksOnTruthVertex;
       }
     }
@@ -510,14 +513,10 @@ ActsExamples::ProcessCode ActsExamples::VertexPerformanceWriter::writeT(
 
       for (std::size_t j = 0; j < associatedTruthParticles.size(); ++j) {
         const auto& particle = associatedTruthParticles[j];
-        int priVtxId = particle.particleId().vertexPrimary();
-        int generation = particle.particleId().generation();
+        SimBarcode vtxId =
+            particle.particleId().setParticle(0).setSubParticle(0);
 
-        if (generation > 0) {
-          // truthparticle from secondary vtx
-          continue;
-        }
-        if (priVtxId == maxOccurrenceId) {
+        if (vtxId == maxOccurrenceId) {
           // Vertex found, fill variables
 
           // Helper function for computing the pull