#include <BFieldComponent3d.h>

Inheritance diagram for BFieldComponent3d:

Collaboration diagram for BFieldComponent3d:

[legend]

Public Member Functions
	BFieldComponent3d ()=default
	The BFieldComponent3d constructor.

virtual	~BFieldComponent3d ()=default
	The BFieldComponent3d destructor.

virtual void	initialize () override
	Initializes the magnetic field component. More...

virtual ROOT::Math::XYZVector	calculate (const ROOT::Math::XYZVector &point) const override
	Calculates the magnetic field vector at the specified space point. More...

virtual void	terminate () override
	Terminates the magnetic field component. More...

void	setMapFilename (const std::string &filename)
	Sets the filename of the magnetic field map. More...

void	setMapSize (int sizeR, int sizePhi, int sizeZ)
	Sets the size of the magnetic field map. More...

void	setMapRegionZ (double minZ, double maxZ, double offset)
	Sets the size of the magnetic field map. More...

void	setMapRegionR (double minR, double maxR)
	Sets the size of the magnetic field map. More...

void	setGridPitch (double pitchR, double pitchPhi, double pitchZ)
	Sets the grid pitch of the magnetic field map. More...

void	setExcludeRegionZ (double minZ, double maxZ)
	Sets the size of the magnetic field map to exclude. More...

void	setExcludeRegionR (double minR, double maxR)
	Sets the size of the magnetic field map to exclude. More...

void	setErrorRegionR (double minR=-1., double maxR=-1., double errBr=0.0, double errBphi=0.0, double errBz=0.0)
	Sets the size of the magnetic field map to apply error on B. More...

void	mirrorPhi (bool mirrorPhi=0.)

void	doInterpolation (bool interpolate=true)

void	enableCoordinate (const std::string &mapEnable="rphiz")
	Option to reduce 3D to 2D map (in coordinates, NOT Br, Bphi, Bz components) More...

Private Member Functions
ROOT::Math::XYZVector	interpolate (unsigned int ir, unsigned int iphi, unsigned int iz, double wr, double wphi, double wz) const
	Interpolate the value of B-field between (ir, iphi, iz) and (ir+1, iphi+1, iz+1) using weights (wr, wphi, wz)

Private Attributes
std::string	m_mapFilename {""}
	The filename of the magnetic field map.

std::vector< ROOT::Math::XYZVector >	m_bmap
	The memory buffer for the magnetic field map.

std::string	m_mapEnable {"rphiz"}
	Enable different dimension, "rphiz", "rphi", "phiz" or "rz" >

bool	m_interpolate {true}
	Flag to switch on/off interpolation >

int	m_mapSize [3]
	The size of the map in r, phi and z.

double	m_mapRegionZ [2] {0}
	The min and max boundaries of the map region in z.

double	m_mapOffset {0}
	Offset required because the accelerator group defines the Belle center as zero.

double	m_mapRegionR [2] {0}
	The min and max boundaries of the map region in r.

double	m_gridPitch [3] {0}
	The grid pitch in r,phi,z.

double	m_igridPitch [3] {0}
	The inverted grid pitch in r,phi,z.

double	m_exRegionZ [2] {0}
	The min and max boundaries of the excluded region in z.

double	m_exRegionR [2] {0}
	The min and max boundaries of the excluded region in r.

bool	m_exRegion {true}
	Flag to indicate whether there is a region to exclude. More...

bool	m_mirrorPhi {true}
	Flag to indicate whether there is a region to exclude. More...

double	m_errRegionR [2] {0}
	The min and max boundaries of the region in r to apply error.

double	m_errB [3] {0}
	The error Br, Bphi, Bz as a scale factor (B_new = m_errB * B_old).

Detailed Description

The BFieldComponent3d class.

This class represents a 3d magnetic field map. The magnetic field map is stored as a grid in cylindrical coordinates. It is defined by a minimum radius and a maximum radius, a minimum z and a maximum z value (phi is assumed to be in 360 degrees range, option to mirror about the x-y plane exist), a pitch size in both, r, z and phi and the number of grid points. The ZOffset is used to account for the fact that the acceleration group defines 0 to be in the center of the detector, while the detector group defines the IP to be the center. The filename points to the zip file containing the magnetic field map.

Definition at line 36 of file BFieldComponent3d.h.

Member Function Documentation

◆ calculate()

ROOT::Math::XYZVector calculate ( const ROOT::Math::XYZVector & point ) const

overridevirtual

Calculates the magnetic field vector at the specified space point.

Parameters

point The space point in [cm] at which the magnetic field vector should be calculated.

Returns: The magnetic field vector at the given space point in [T]. Returns a zero vector XYZVector(0,0,0) if the space point lies outside the region described by the component.

Implements BFieldComponentAbs.

Definition at line 187 of file BFieldComponent3d.cc.

 {
   auto getPhiIndexWeight = [this](double y, double x, double & wphi) -> unsigned int {
     double phi = fast_atan2_minimax<4>(y, x);
     wphi = phi * m_igridPitch[1];
     auto iphi = static_cast<unsigned int>(wphi);
     iphi = min(iphi, static_cast<unsigned int>(m_mapSize[1] - 2));
     wphi -= iphi;
     return iphi;
   };
  
   ROOT::Math::XYZVector B(0, 0, 0);
  
   // If both '3d' and 'Beamline' components are defined in xml file,
   // '3d' component returns zero field where 'Beamline' component is defined.
   // If no 'Beamline' component is defined in xml file, the following function will never be called.
   if (BFieldComponentBeamline::Instance().isInRange(point)) {
     return B;
   }
  
   double z = point.Z();
   // Check if the point lies inside the magnetic field boundaries
   if (z < m_mapRegionZ[0] || z > m_mapRegionZ[1]) return B;
  
   double r2 = point.Perp2();
   // Check if the point lies inside the magnetic field boundaries
   if (r2 < m_mapRegionR[0]*m_mapRegionR[0] || r2 >= m_mapRegionR[1]*m_mapRegionR[1]) return B;
   // Check if the point lies in the exclude region
   if (m_exRegion && (z >= m_exRegionZ[0]) && (z < m_exRegionZ[1]) &&
       (r2 >= m_exRegionR[0]*m_exRegionR[0]) && (r2 < m_exRegionR[1]*m_exRegionR[1])) return B;
  
   // Calculate the lower index of the point in the Z grid
   // Note that z coordinate is inverted to match ANSYS frame
   double wz = (m_mapRegionZ[1] - z) * m_igridPitch[2];
   unsigned int iz = static_cast<int>(wz);
   iz = min(iz, static_cast<unsigned int>(m_mapSize[2] - 2));
   wz -= iz;
  
   if (r2 > 0) {
     double r = sqrt(r2);
  
     // Calculate the lower index of the point in the R grid
     double wr = (r - m_mapRegionR[0]) * m_igridPitch[0];
     auto ir = static_cast<unsigned int>(wr);
     ir = min(ir, static_cast<unsigned int>(m_mapSize[0] - 2));
     wr -= ir;
  
     // Calculate the lower index of the point in the Phi grid
     double ay = std::abs(point.Y());
     double wphi;
     unsigned int iphi = getPhiIndexWeight(ay, point.X(), wphi);
  
     // Get B-field values from map
     ROOT::Math::XYZVector b = interpolate(ir, iphi, iz, wr, wphi, wz); // in cylindrical system
     double norm = 1 / r;
     double s = ay * norm, c = point.X() * norm;
     // Flip sign of By if y<0
     const double sgny = (point.Y() >= 0) - (point.Y() < 0);
     // in cartesian system
     B.SetXYZ(-(b.X() * c - b.Y() * s), -sgny * (b.X() * s + b.Y() * c), b.Z());
   } else {
     // Get B-field values from map in cartesian system assuming phi=0, so Bx = Br and By = Bphi
     B = interpolate(0, 0, iz, 0, 0, wz);
   }
  
   return B;
 }

◆ doInterpolation()

void doInterpolation ( bool interpolate = true )

inline

Parameters

interpolate Flag to switch on/off interpolation

Definition at line 137 of file BFieldComponent3d.h.

137 { m_interpolate = interpolate; }

Belle2::BFieldComponent3d::m_interpolate

bool m_interpolate

Flag to switch on/off interpolation >

Definition: BFieldComponent3d.h:160

◆ enableCoordinate()

void enableCoordinate ( const std::string & mapEnable = "rphiz" )

inline

Option to reduce 3D to 2D map (in coordinates, NOT Br, Bphi, Bz components)

Parameters

mapEnable List of dimensions to enable: "rphiz", "rphi", "phiz" or "rz"

Definition at line 143 of file BFieldComponent3d.h.

◆ initialize()

void initialize ( void )

overridevirtual

Initializes the magnetic field component.

This method opens the magnetic field map file.

Reimplemented from BFieldComponentAbs.

Definition at line 27 of file BFieldComponent3d.cc.

◆ mirrorPhi()

void mirrorPhi ( bool mirrorPhi = 0. )

inline

Parameters

mirrorPhi Flag to enable mirroring in phi about x-z plane

Definition at line 132 of file BFieldComponent3d.h.

◆ setErrorRegionR()

void setErrorRegionR	(	double	minR = `-1.`,
		double	maxR = `-1.`,
		double	errBr = `0.0`,
		double	errBphi = `0.0`,
		double	errBz = `0.0`
	)

inline

Sets the size of the magnetic field map to apply error on B.

Parameters

minR	The left (min) border of the magnetic field map region in r [m] -> [cm].
maxR	The right (max) border of the magnetic field map region in r [m] -> [cm].
errBr	The size of the error on Br, Br_new = errBr*Br [fraction].
errBphi	The size of the error on Bphi, Bphi_new = errBphi*Bphi [fraction].
errBz	The size of the error on Bz, Bz_new = errBz*Bz [fraction].

Definition at line 126 of file BFieldComponent3d.h.

◆ setExcludeRegionR()

void setExcludeRegionR	(	double	minR,
		double	maxR
	)

inline

Sets the size of the magnetic field map to exclude.

Parameters

minR	The left (min) border of the magnetic field map region in r [m] -> [cm].
maxR	The right (max) border of the magnetic field map region in r [m] -> [cm].

Definition at line 116 of file BFieldComponent3d.h.

◆ setExcludeRegionZ()

void setExcludeRegionZ	(	double	minZ,
		double	maxZ
	)

inline

Sets the size of the magnetic field map to exclude.

Parameters

minZ	The left (min) border of the magnetic field map region in z [m] -> [cm].
maxZ	The right (max) border of the magnetic field map region in z [m] -> [cm].

Definition at line 109 of file BFieldComponent3d.h.

◆ setGridPitch()

void setGridPitch	(	double	pitchR,
		double	pitchPhi,
		double	pitchZ
	)

inline

Sets the grid pitch of the magnetic field map.

Parameters

pitchR	The pitch of the grid in r [m] -> [cm].
pitchPhi	The pitch of the grid in phi [degrees] -> [rad] converted back to degrees in the code.
pitchZ	The pitch of the grid in z [m] -> [cm].

Definition at line 102 of file BFieldComponent3d.h.

◆ setMapFilename()

void setMapFilename ( const std::string & filename )

inline

Sets the filename of the magnetic field map.

Parameters

filename The filename of the magnetic field map.

Definition at line 71 of file BFieldComponent3d.h.

◆ setMapRegionR()

void setMapRegionR	(	double	minR,
		double	maxR
	)

inline

Sets the size of the magnetic field map.

Parameters

minR	The left (min) border of the magnetic field map region in r [m] -> [cm].
maxR	The right (max) border of the magnetic field map region in r [m] -> [cm].

Definition at line 94 of file BFieldComponent3d.h.

◆ setMapRegionZ()

void setMapRegionZ	(	double	minZ,
		double	maxZ,
		double	offset
	)

inline

Sets the size of the magnetic field map.

Parameters

minZ	The left (min) border of the magnetic field map region in z [m] -> [cm].
maxZ	The right (max) border of the magnetic field map region in z [m] -> [cm].
offset	The offset in z [m] -> [cm] which is required because the accelerator group defines the Belle center as zero.

Definition at line 87 of file BFieldComponent3d.h.

◆ setMapSize()

void setMapSize	(	int	sizeR,
		int	sizePhi,
		int	sizeZ
	)

inline

Sets the size of the magnetic field map.

Parameters

sizeR	The number of points in the r direction.
sizePhi	The number of points in the phi direction.
sizeZ	The number of points in the z direction.

Definition at line 79 of file BFieldComponent3d.h.

◆ terminate()

void terminate ( void )

overridevirtual

Terminates the magnetic field component.

This method closes the magnetic field map file.

Reimplemented from BFieldComponentAbs.

Definition at line 255 of file BFieldComponent3d.cc.

Member Data Documentation

◆ m_exRegion

bool m_exRegion {true}

private

Flag to indicate whether there is a region to exclude.

>

Definition at line 178 of file BFieldComponent3d.h.

◆ m_mirrorPhi

bool m_mirrorPhi {true}

private

Flag to indicate whether there is a region to exclude.

>

Definition at line 180 of file BFieldComponent3d.h.

The documentation for this class was generated from the following files:

geometry/bfieldmap/include/BFieldComponent3d.h
geometry/bfieldmap/src/BFieldComponent3d.cc

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Member Function Documentation

◆ calculate()

◆ doInterpolation()

◆ enableCoordinate()

◆ initialize()

◆ mirrorPhi()

◆ setErrorRegionR()

◆ setExcludeRegionR()

◆ setExcludeRegionZ()

◆ setGridPitch()

◆ setMapFilename()

◆ setMapRegionR()

◆ setMapRegionZ()

◆ setMapSize()

◆ terminate()

Member Data Documentation

◆ m_exRegion

◆ m_mirrorPhi