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TruthTrackFinder.cpp
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1 // This file is part of the Acts project.
2 //
3 // Copyright (C) 2019 CERN for the benefit of the Acts project
4 //
5 // This Source Code Form is subject to the terms of the Mozilla Public
6 // License, v. 2.0. If a copy of the MPL was not distributed with this
7 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
8 
10 
11 #include <algorithm>
12 #include <stdexcept>
13 #include <vector>
14 
20 
21 using namespace FW;
22 
24  : BareAlgorithm("TruthTrackFinder", lvl), m_cfg(cfg) {
25  if (m_cfg.inputParticles.empty()) {
26  throw std::invalid_argument("Missing input truth particles collection");
27  }
28  if (m_cfg.inputHitParticlesMap.empty()) {
29  throw std::invalid_argument("Missing input hit-particles map collection");
30  }
31  if (m_cfg.outputProtoTracks.empty()) {
32  throw std::invalid_argument("Missing output proto tracks collection");
33  }
34 }
35 
37  using HitParticlesMap = IndexMultimap<ActsFatras::Barcode>;
38 
39  // prepare input collections
40  const auto& particles =
42  const auto& hitParticlesMap =
43  ctx.eventStore.get<HitParticlesMap>(m_cfg.inputHitParticlesMap);
44  // compute particle_id -> {hit_id...} map from the
45  // hit_id -> {particle_id...} map on the fly.
46  const auto& particleHitsMap = invertIndexMultimap(hitParticlesMap);
47 
48  // prepare output collection
49  ProtoTrackContainer tracks;
50  tracks.reserve(particles.size());
51 
52  // create prototracks for all input particles
53  for (const auto& particle : particles) {
54  // find the corresponding hits for this particle
55  const auto& hits =
56  makeRange(particleHitsMap.equal_range(particle.particleId()));
57  // fill hit indices to create the proto track
59  track.reserve(hits.size());
60  for (const auto& hit : hits) {
61  track.emplace_back(hit.second);
62  }
63  // add proto track to the output collection
64  tracks.emplace_back(std::move(track));
65  }
66 
67  ctx.eventStore.add(m_cfg.outputProtoTracks, std::move(tracks));
68  return ProcessCode::SUCCESS;
69 }