feat: Initial version of ATLAS-based FTF seeding (#2227)

First few files needed for FTF seeding. Does not create seeds yet, made
to check current progress is compatible.

Author: Rosie-Hasan

Core/include/Acts/Seeding/GNN_DataStorage.hpp

@@ -0,0 +1,319 @@
+// This file is part of the Acts project.
+//
+// Copyright (C) 2021 CERN for the benefit of the Acts project
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#pragma once
+
+// TODO: update to C++17 style
+#include "Acts/Definitions/Algebra.hpp"
+#include "Acts/Seeding/GNN_Geometry.hpp"
+
+#include <algorithm>
+#include <map>
+#include <vector>
+
+namespace Acts {
+
+constexpr size_t MAX_SEG_PER_NODE = 1000;  // was 30
+constexpr size_t N_SEG_CONNS = 6;          // was 6
+
+// new sp struct
+template <typename space_point_t>
+struct FTF_SP {
+  const space_point_t *SP;  // want inside to have pointer
+  int FTF_ID;
+  int combined_ID;
+  FTF_SP(const space_point_t *sp, int id, int combined_id)
+      : SP(sp), FTF_ID(id), combined_ID{combined_id} {
+    if (SP->sourceLinks().size() == 1) {  // pixels have 1 SL
+      m_isPixel = true;
+    } else {
+      m_isPixel = false;
+    }
+    m_phi = std::atan(SP->x() / SP->y());
+  };
+  bool isPixel() const { return m_isPixel; }
+  bool isSCT() const { return !m_isPixel; }
+  float phi() const { return m_phi; }
+  bool m_isPixel;
+  float m_phi;
+};
+
+template <typename space_point_t>
+class TrigFTF_GNN_Node {
+ public:
+  struct CompareByPhi {
+    bool operator()(const TrigFTF_GNN_Node<space_point_t> *n1,
+                    const TrigFTF_GNN_Node<space_point_t> *n2) {
+      return (n1->m_sp_FTF.phi() < n2->m_sp_FTF.phi());
+    }
+  };
+
+  TrigFTF_GNN_Node(const FTF_SP<space_point_t> &FTF_sp, float minT = -100.0,
+                   float maxT = 100.0)
+      : m_sp_FTF(FTF_sp), m_minCutOnTau(minT), m_maxCutOnTau(maxT) {}
+
+  ~TrigFTF_GNN_Node() {}
+
+  inline void addIn(int i) {
+    if (m_in.size() < MAX_SEG_PER_NODE) {
+      m_in.push_back(i);
+    }
+  }
+
+  inline void addOut(int i) {
+    if (m_out.size() < MAX_SEG_PER_NODE) {
+      m_out.push_back(i);
+    }
+  }
+
+  inline bool isConnector() const {
+    if (m_in.empty() || m_out.empty())
+      return false;
+    return true;
+  }
+
+  inline bool isFull() const {
+    if (m_in.size() == MAX_SEG_PER_NODE && m_out.size() == MAX_SEG_PER_NODE)
+      return true;
+    else
+      return false;
+  }
+
+  const FTF_SP<space_point_t> &m_sp_FTF;
+
+  std::vector<unsigned int> m_in;  // indices of the edges in the edge storage
+  std::vector<unsigned int> m_out;
+  float m_minCutOnTau, m_maxCutOnTau;
+};
+
+template <typename space_point_t>
+class TrigFTF_GNN_EtaBin {
+ public:
+  TrigFTF_GNN_EtaBin() { m_vn.clear(); }
+
+  ~TrigFTF_GNN_EtaBin() {
+    for (typename std::vector<TrigFTF_GNN_Node<space_point_t> *>::iterator it =
+             m_vn.begin();
+         it != m_vn.end(); ++it) {
+      delete (*it);
+    }
+  }
+
+  void sortByPhi() {
+    std::sort(m_vn.begin(), m_vn.end(),
+              typename Acts::TrigFTF_GNN_Node<space_point_t>::CompareByPhi());
+  }
+
+  bool empty() const { return m_vn.empty(); }
+
+  void generatePhiIndexing(float dphi) {
+    for (unsigned int nIdx = 0; nIdx < m_vn.size(); nIdx++) {
+      TrigFTF_GNN_Node<space_point_t> *pN = m_vn.at(nIdx);
+      // float phi = pN->m_sp.phi();
+      // float phi = (std::atan(pN->m_sp.x() / pN->m_sp.y()));
+      float phi = pN->m_sp_FTF.phi();
+      if (phi <= M_PI - dphi) {
+        continue;
+      }
+
+      m_vPhiNodes.push_back(
+          std::pair<float, unsigned int>(phi - 2 * M_PI, nIdx));
+    }
+
+    for (unsigned int nIdx = 0; nIdx < m_vn.size(); nIdx++) {
+      TrigFTF_GNN_Node<space_point_t> *pN = m_vn.at(nIdx);
+      float phi = pN->m_sp_FTF.phi();
+      m_vPhiNodes.push_back(std::pair<float, unsigned int>(phi, nIdx));
+    }
+
+    for (unsigned int nIdx = 0; nIdx < m_vn.size(); nIdx++) {
+      TrigFTF_GNN_Node<space_point_t> *pN = m_vn.at(nIdx);
+      float phi = pN->m_sp_FTF.phi();
+      if (phi >= -M_PI + dphi) {
+        break;
+      }
+      m_vPhiNodes.push_back(
+          std::pair<float, unsigned int>(phi + 2 * M_PI, nIdx));
+    }
+  }
+
+  std::vector<TrigFTF_GNN_Node<space_point_t> *> m_vn;
+  // TODO change to
+  // std::vector<std::unique_ptr<TrigFTF_GNN_Node<space_point_t>>> m_vn;
+  std::vector<std::pair<float, unsigned int>> m_vPhiNodes;
+};
+
+template <typename space_point_t>
+class TrigFTF_GNN_DataStorage {
+ public:
+  TrigFTF_GNN_DataStorage(const TrigFTF_GNN_Geometry<space_point_t> &g)
+      : m_geo(g) {
+    m_etaBins.reserve(g.num_bins());
+    for (int k = 0; k < g.num_bins(); k++) {
+      m_etaBins.emplace_back(TrigFTF_GNN_EtaBin<space_point_t>());
+    }
+  }
+
+  ~TrigFTF_GNN_DataStorage() {}
+
+  int addSpacePoint(const FTF_SP<space_point_t> &sp, bool useClusterWidth) {
+    const TrigFTF_GNN_Layer<space_point_t> *pL =
+        m_geo.getTrigFTF_GNN_LayerByKey(sp.combined_ID);
+
+    if (pL == nullptr) {
+      return -1;
+    }
+
+    int binIndex = pL->getEtaBin(sp.SP->z(), sp.SP->r());
+
+    if (binIndex == -1) {
+      return -2;
+    }
+
+    bool isBarrel = (pL->m_layer.m_type == 0);
+
+    if (isBarrel) {
+      float min_tau = -100.0;
+      float max_tau = 100.0;
+      // can't do this bit yet as dont have cluster width
+      if (useClusterWidth) {
+        //   const Trk::SpacePoint* osp = sp.offlineSpacePoint();
+        //   const InDet::PixelCluster* pCL = dynamic_cast<const
+        //   InDet::PixelCluster*>(osp->clusterList().first);
+        //   float cluster_width = pCL->width().widthPhiRZ().y();
+        float cluster_width = 1;  // temporary while cluster width not available
+        min_tau = 6.7 * (cluster_width - 0.2);
+        max_tau =
+            1.6 + 0.15 / (cluster_width + 0.2) + 6.1 * (cluster_width - 0.2);
+      }
+
+      m_etaBins.at(binIndex).m_vn.push_back(new TrigFTF_GNN_Node<space_point_t>(
+          sp, min_tau, max_tau));  // adding ftf member to nodes
+    } else {
+      if (useClusterWidth) {
+        //   const Trk::SpacePoint* osp = sp.offlineSpacePoint();
+        //   const InDet::PixelCluster* pCL = dynamic_cast<const
+        //   InDet::PixelCluster*>(osp->clusterList().first);
+        //   float cluster_width = pCL->width().widthPhiRZ().y();
+        float cluster_width = 1;  // temporary while cluster width not available
+        if (cluster_width > 0.2) {
+          return -3;
+        }
+      }
+      m_etaBins.at(binIndex).m_vn.push_back(
+          new TrigFTF_GNN_Node<space_point_t>(sp));
+    }
+
+    return 0;
+  }
+
+  // for safety to prevent passing as copy
+  TrigFTF_GNN_DataStorage(const TrigFTF_GNN_DataStorage &) = delete;
+  TrigFTF_GNN_DataStorage &operator=(const TrigFTF_GNN_DataStorage &) = delete;
+
+  unsigned int numberOfNodes() const {
+    unsigned int n = 0;
+
+    for (auto &b : m_etaBins) {
+      n += b.m_vn.size();
+    }
+    return n;
+  }
+
+  void getConnectingNodes(
+      std::vector<const TrigFTF_GNN_Node<space_point_t> *> &vn) {
+    vn.clear();
+    vn.reserve(numberOfNodes());
+    for (const auto &b : m_etaBins) {
+      for (typename std::vector<
+               TrigFTF_GNN_Node<space_point_t> *>::const_iterator nIt =
+               b.m_vn.begin();
+           nIt != b.m_vn.end(); ++nIt) {
+        if ((*nIt)->m_in.empty()) {
+          continue;
+        }
+        if ((*nIt)->m_out.empty()) {
+          continue;
+        }
+        vn.push_back(*nIt);
+      }
+    }
+  }
+
+  void sortByPhi() {
+    for (auto &b : m_etaBins) {
+      b.sortByPhi();
+    }
+  }
+
+  void generatePhiIndexing(float dphi) {
+    for (auto &b : m_etaBins) {
+      b.generatePhiIndexing(dphi);
+    }
+  }
+
+  const TrigFTF_GNN_EtaBin<space_point_t> &getEtaBin(int idx) const {
+    if (idx >= static_cast<int>(m_etaBins.size())) {
+      idx = idx - 1;
+    }
+    return m_etaBins.at(idx);
+  }
+
+ protected:
+  const TrigFTF_GNN_Geometry<space_point_t> &m_geo;
+
+  std::vector<TrigFTF_GNN_EtaBin<space_point_t>> m_etaBins;
+};
+
+template <typename space_point_t>
+class TrigFTF_GNN_Edge {
+ public:
+  struct CompareLevel {
+   public:
+    bool operator()(const TrigFTF_GNN_Edge *pS1, const TrigFTF_GNN_Edge *pS2) {
+      return pS1->m_level > pS2->m_level;
+    }
+  };
+
+  TrigFTF_GNN_Edge(TrigFTF_GNN_Node<space_point_t> *n1,
+                   TrigFTF_GNN_Node<space_point_t> *n2, float p1, float p2,
+                   float p3, float p4)
+      : m_n1(n1), m_n2(n2), m_level(1), m_next(1), m_nNei(0) {
+    m_p[0] = p1;
+    m_p[1] = p2;
+    m_p[2] = p3;
+    m_p[3] = p4;
+  }
+
+  TrigFTF_GNN_Edge()
+      : m_n1(nullptr), m_n2(nullptr), m_level(-1), m_next(-1), m_nNei(0){};
+
+  // TrigFTF_GNN_Edge(const TrigFTF_GNN_Edge<space_point_t> &e)
+  //     : m_n1(e.m_n1), m_n2(e.m_n2){};
+
+  // inline void initialize(TrigFTF_GNN_Node<space_point_t> *n1,
+  //                        TrigFTF_GNN_Node<space_point_t> *n2) {
+  //   m_n1 = n1;
+  //   m_n2 = n2;
+  //   m_level = 1;
+  //   m_next = 1;
+  //   m_nNei = 0;
+  // }
+
+  TrigFTF_GNN_Node<space_point_t> *m_n1{nullptr};
+  TrigFTF_GNN_Node<space_point_t> *m_n2{nullptr};
+
+  signed char m_level{-1}, m_next{-1};
+
+  unsigned char m_nNei{0};
+  float m_p[4]{};
+
+  unsigned int m_vNei[N_SEG_CONNS]{};  // global indices of the connected edges
+};
+
+}  // namespace Acts