AtlasFieldMap.h

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/*
  Copyright (C) 2002-2024 CERN for the benefit of the ATLAS collaboration
*/
 
#ifndef MAGFIELDCONDITIONS_ATLASFIELDMAP_H
#define MAGFIELDCONDITIONS_ATLASFIELDMAP_H 1
 
// MagField includes
#include "CxxUtils/restrict.h"
#include "GaudiKernel/ServiceHandle.h"
#include "MagFieldElements/BFieldCache.h"
#include "MagFieldElements/BFieldCacheZR.h"
#include "MagFieldElements/BFieldCond.h"
#include "MagFieldElements/BFieldMeshZR.h"
#include "MagFieldElements/BFieldZone.h"
 
#include <iostream>
#include <memory>
 
// forward declarations
class TFile;
 
namespace MagField {
 
class AtlasFieldMap
{
public:
  AtlasFieldMap() = default;
  ~AtlasFieldMap() { delete m_meshZR; }
 
  // initialize map from root file
  bool initializeMap(TFile* rootfile,
                     float solenoidCurrent,
                     float toroidCurrent);
 
  // Functions used by getField[ZR] in AtlasFieldCache
  // search for a "zone" to which the point (z,r,phi) belongs
  const BFieldZone* findBFieldZone(double z, double r, double phi) const;
 
  // fast 2d map (made of one zone)
  const BFieldMeshZR* getBFieldMesh() const;
 
  bool solenoidOn() const { return solenoidCurrent() > 0.0; }
  bool toroidOn() const { return toroidCurrent() > 0.0; }
  // magnet currents read with map - needed for scaling
  float solenoidCurrent() const { return m_solenoidCurrent; }
  float toroidCurrent() const { return m_toroidCurrent; }
  int solenoidZoneId() const { return m_solenoidZoneId; }
 
private:
  AtlasFieldMap& operator=(AtlasFieldMap&& other) = delete;
  AtlasFieldMap(const AtlasFieldMap& other) = delete;
  AtlasFieldMap& operator=(const AtlasFieldMap& other) = delete;
  AtlasFieldMap(AtlasFieldMap&& other) = delete;
 
  // slow zone search is used during initialization to build the LUT
  BFieldZone* findZoneSlow(double z, double r, double phi);
 
  // utility functions used by readMap
  int read_packed_data(std::istream& input, std::vector<int>& data) const;
  int read_packed_int(std::istream& input, int& n) const;
  void buildLUT();
  void buildZR();
 
  int memSize() const;
 
  // field map name
  std::string m_filename;
 
  // currents read in with map
  float m_solenoidCurrent{ 0 }; // solenoid current in ampere
  float m_toroidCurrent{ 0 };   // toroid current in ampere
  int m_solenoidZoneId{ -1 };   // solenoid zone id
 
  // full 3d map (made of multiple zones)
  std::vector<BFieldZone> m_zone;
 
  // fast 2d map (made of one zone)
  BFieldMeshZR* m_meshZR{ nullptr };
 
  // data members used in zone-finding
  std::vector<double> m_edge[3];            // zone boundaries in z, r, phi
  std::vector<int> m_edgeLUT[3];            // look-up table for zone edges
  double m_invq[3]{};                       // 1/stepsize in m_edgeLUT
  std::vector<const BFieldZone*> m_zoneLUT; // look-up table for zones
  // more data members to speed up zone-finding
  double m_zmin{ 0 }; // minimum z
  double m_zmax{ 0 }; // maximum z
  int m_nz{ 0 };      // number of z bins in zoneLUT
  double m_rmax{ 0 }; // maximum r
  int m_nr{ 0 };      // number of r bins in zoneLUT
  int m_nphi{ 0 };    // number of phi bins in zoneLUT
  bool m_mapIsInitialized{ false };
};
 
} // namespace MagField
 
#include "AtlasFieldMap.icc"
#endif // MAGFIELDCONDITIONS_ATLASFIELDMAP_H