G4FieldUtils.hh

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//
// Helper namespace field_utils
//
// Description:
//
// Simple methods to extract vectors from arrays in conventions of
// the magnetic field integration.
 
// Author: Dmitry Sorokin (CERN, Google Summer of Code 2017), 13.10.2017
// Supervision: John Apostolakis (CERN)
// --------------------------------------------------------------------
#ifndef G4FIELD_UTILS_HH
#define G4FIELD_UTILS_HH
 
#include "G4FieldTrack.hh"
#include "G4Types.hh"
#include "G4ThreeVector.hh"
 
/**
 * @brief field_utils is a helper namespace, including simple methods to extract
 * vectors from arrays in conventions of the magnetic field integration.
 */
 
namespace field_utils
{
  using State = G4double[G4FieldTrack::ncompSVEC];
 
  template <unsigned int N>
  using ShortState = G4double[N];
   
  enum class Value3D
  {
    Position = 0,
    Momentum = 3,
    Spin = 9
  };
 
  enum class Value1D
  {
    KineticEnergy = 6,
    LabTime = 7,
    ProperTime = 8
  };
 
  template <typename ArrayType>
  G4double getValue(const ArrayType& array, Value1D value);
 
  template <typename ArrayType>
  G4double getValue2(const ArrayType& array, Value1D value);
 
  template <typename ArrayType>
  G4double getValue(const ArrayType& array, Value3D value);
 
  template <typename ArrayType>
  G4double getValue2(const ArrayType& array, Value3D value);
 
  template <typename ArrayType>
  G4ThreeVector makeVector(const ArrayType& array, Value3D value);
 
  G4double absoluteError(
    const G4double y[],
    const G4double yerr[],
    G4double hstep);
 
  G4double relativeError2(
    const G4double y[],
    const G4double yerr[],
    G4double hstep,
    G4double errorTolerance);
 
  G4double relativeError(
    const G4double y[],
    const G4double yerr[],
    G4double hstep,
    G4double errorTolerance);
 
  template <typename SourceArray, typename TargetArray>
  void setValue(const SourceArray& src, Value1D value, TargetArray& trg);
 
  template <typename SourceArray, typename TargetArray, typename ...TargetArrays>
  void setValue(const SourceArray& src, Value1D value,
                TargetArray& trg, TargetArrays&... trgs);
 
  void copy(G4double dst[], const G4double src[],
            std::size_t size = G4FieldTrack::ncompSVEC);
 
  G4double inverseCurvatureRadius(G4double particleCharge,
                                  G4double momentum, G4double BField);
 
  template <typename T>
  T clamp(T value, T lo, T hi);
}
 
#include "G4FieldUtils.icc"
 
#endif