BFieldManager.h

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
 
#pragma once
 
#include <Math/Vector3D.h>
#include <framework/logging/Logger.h>
#include <framework/gearbox/Unit.h>
#include <framework/database/DBObjPtr.h>
#include <framework/dbobjects/MagneticField.h>
 
namespace Belle2 {
  class BFieldManager {
  public:
    static void getField(const double* pos, double* field);
    static ROOT::Math::XYZVector getField(double x, double y, double z)
    {
      return getField(ROOT::Math::XYZVector(x, y, z));
    }
    static ROOT::Math::XYZVector getField(const ROOT::Math::XYZVector& pos)
    {
      return BFieldManager::getInstance().calculate(pos);
    }
    static ROOT::Math::XYZVector getFieldInTesla(const ROOT::Math::XYZVector& pos)
    {
      return getField(pos) / Unit::T;
    }
    static BFieldManager& getInstance();
  private:
    BFieldManager() = default;
    BFieldManager(BFieldManager&) = delete;
    BFieldManager& operator=(const BFieldManager&) = delete;
    ~BFieldManager() = default;
    ROOT::Math::XYZVector calculate(const ROOT::Math::XYZVector& pos) const;
    DBObjPtr<MagneticField> m_magfield;
  };
 
  inline ROOT::Math::XYZVector BFieldManager::calculate(const ROOT::Math::XYZVector& pos) const
  {
    if (!m_magfield) B2FATAL("Could not load magnetic field configuration from database");
    return m_magfield->getField(pos);
  };
 
  inline void BFieldManager::getField(const double* pos, double* field)
  {
    ROOT::Math::XYZVector fieldvec = getField(ROOT::Math::XYZVector(pos[0], pos[1], pos[2]));
    field[0] = fieldvec.X();
    field[1] = fieldvec.Y();
    field[2] = fieldvec.Z();
  }
}