geometry

Topics
	geometry data objects
	geometry modules

Namespaces
namespace	Belle2::geometry
	Common code concerning the geometry representation of the detector.

Classes
class	BFieldComponent3d
	The BFieldComponent3d class. More...
class	BFieldComponentAbs
	The BFieldComponentAbs class. More...
class	BFieldComponentBeamline
	The BFieldComponentBeamline class. More...
class	BFieldComponentConstant
	The BFieldComponentConstant class. More...
class	BFieldComponentKlm1
	The Bfieldcomponentklm1 class. More...
class	BFieldComponentQuad
	The BFieldComponentQuad class. More...
class	BFieldComponentRadial
	The BFieldComponentRadial class. More...
class	BFieldFrameworkInterface
	Simple BFieldComponent to just wrap the existing BFieldMap with the new BFieldManager. More...
class	BFieldMap
	This class represents the magnetic field of the Belle II detector. More...
class	GeoMagneticField
	The GeoMagneticField class. More...
struct	triangle_t
	Triangle structure. More...
struct	xy_t
	A simple 2d vector structure. More...
class	TriangularInterpolation
	The TriangularInterpolation class. More...
class	BeamlineFieldMapInterpolation
	The BeamlineFieldMapInterpolation class. More...
class	GeoComponent
	Describe one component of the Geometry. More...
class	GeoConfiguration
	configuration of the geometry More...
class	GeoMaterial
	Class to represent a material information in the Database. More...
class	GeoMaterialComponent
	Component of a material. More...
class	GeoMaterialProperty
	Property of a material. More...
class	GeoOpticalSurface
	Represent an optical finish of a surface. More...
class	MagneticFieldComponent3D
	Describe one component of the Geometry. More...
class	MyDBPayloadClass
	Class containing all the parameters needed to create the geometry and suitable to save into a ROOT file to be used from the Database. More...
class	MyDBCreator
	Very simple Creator class which actually does not do anything but shows how creators should implement loading the geometry from database. More...

Functions
BFieldComponentBeamline **	GetInstancePtr ()
	Static function holding the instance.
BFieldComponentRadial::BFieldPoint	operator* (const BFieldComponentRadial::BFieldPoint &v, double a)
	multiply a radial bfield point by a real number
BFieldComponentRadial::BFieldPoint	operator+ (const BFieldComponentRadial::BFieldPoint &u, const BFieldComponentRadial::BFieldPoint &v)
	Add two radial bfield points together.
template<class BFIELDCOMP>
BFIELDCOMP &	addBFieldComponent ()
	Adds a new BField component to the Belle II magnetic field.
ROOT::Math::XYZVector	getBField (const ROOT::Math::XYZVector &point) const
	Returns the magnetic field of the Belle II detector at the specified space point.
virtual void	initialize () override
	Initializes the magnetic field component.
virtual	~BFieldComponentBeamline ()
	The BFieldComponentBeamline destructor.
bool	isInRange (const ROOT::Math::XYZVector &point) const
	Check presence of beamline field at the specific space point in the detector coordinate frame.
virtual ROOT::Math::XYZVector	calculate (const ROOT::Math::XYZVector &point) const override
	Calculates the magnetic field vector at the specified space point.
virtual void	terminate () override
	Terminates the magnetic field component.
static BFieldComponentBeamline &	Instance ()
	BFieldComponentBeamline instance.
	BFieldComponentBeamline ()
	The BFieldComponentBeamline constructor.
ROOT::Math::XYZVector	getField (const ROOT::Math::XYZVector &pos) const override
	return the field assuming we are inside the active region as returned by inside()
ROOT::Math::XYZVector	interpolate (unsigned int ir, unsigned int iphi, unsigned int iz, double wr, double wphi, double wz) const
	Linear interpolate the magnetic field inside a bin.

Detailed Description

Function Documentation

addBFieldComponent()

template<class BFIELDCOMP>

BFIELDCOMP & addBFieldComponent

(

)

Adds a new BField component to the Belle II magnetic field.

The class of the magnetic field component has to inherit from BFieldComponentAbs.

Returns

A reference to the added magnetic field component.

Definition at line 98 of file BFieldMap.h.

  {
    BFIELDCOMP* newComponent = new BFIELDCOMP;
    m_components.push_back(newComponent);
    return *newComponent;
  }

BFieldComponentBeamline()

BFieldComponentBeamline

(

)

The BFieldComponentBeamline constructor.

Definition at line 707 of file BFieldComponentBeamline.cc.

  {
    auto gInstance = GetInstancePtr();
    if (*gInstance != nullptr) {
      B2WARNING("BFieldComponentBeamline: object already instantiated");
    } else {
      *gInstance = this;
    }
  }

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 Cartesian coordinates (x,y,z) 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 661 of file BFieldComponentBeamline.cc.

  {
    ROOT::Math::XYZVector res;
    double s = m_sinBeamCrossAngle, c = m_cosBeamCrossAngle;
    ROOT::Math::XYZVector v = -p; // invert coordinates to match ANSYS one
    double xc = v.X() * c, zs = v.Z() * s, zc = v.Z() * c, xs = v.X() * s;
    ROOT::Math::XYZVector hv{xc - zs, v.Y(), zc + xs};
    ROOT::Math::XYZVector lv{xc + zs, v.Y(), zc - xs};
    ROOT::Math::XYZVector hb = m_her->interpolateField(hv);
    ROOT::Math::XYZVector lb = m_ler->interpolateField(lv);
    ROOT::Math::XYZVector rhb{hb.X()* c + hb.Z()* s, hb.Y(),  hb.Z()* c - hb.X()* s};
    ROOT::Math::XYZVector rlb{lb.X()* c - lb.Z()* s, lb.Y(),  lb.Z()* c + lb.X()* s};
 
    double mhb = std::abs(rhb.X()) + std::abs(rhb.Y()) + std::abs(rhb.Z());
    double mlb = std::abs(rlb.X()) + std::abs(rlb.Y()) + std::abs(rlb.Z());
 
    if (mhb < 1e-10) res = rlb;
    else if (mlb < 1e-10) res = rhb;
    else {
      res = 0.5 * (rlb + rhb);
    }
    return res;
  }

getBField()

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

inlineprivate

Returns the magnetic field of the Belle II detector at the specified space point.

The space point is given in Cartesian coordinates (x,y,z) in [cm].

Parameters

point

The space point in Cartesian coordinates.

Returns

A three vector of the magnetic field in [T] at the specified space point.

Definition at line 106 of file BFieldMap.h.

  {
    ROOT::Math::XYZVector magFieldVec(0.0, 0.0, 0.0);
    //Check that the point makes sense
    if (std::isnan(point.X()) || std::isnan(point.Y()) || std::isnan(point.Z())) {
      B2ERROR("Bfield requested for a position containing NaN, returning field 0");
      return magFieldVec;
    }
    //Loop over all magnetic field components and add their magnetic field vectors
    for (const BFieldComponentAbs* comp : m_components) {
      magFieldVec += comp->calculate(point);
    }
    return magFieldVec;
  }

getField()

ROOT::Math::XYZVector getField ( const ROOT::Math::XYZVector & pos ) const

overridevirtual

return the field assuming we are inside the active region as returned by inside()

small helper function to calculate the bin index and fraction inside the index given a relative coordinate and the coordinate index (0=R, 1=Phi, 2=Z).

Example: If the z grid starts at 5 and goes to 15 with 6 points (pitch size of 2), then calling getIndexWeight(10.5, 2) will return tuple(2, 0.75) since the 10.5 lies in bin "2" and is already 75% to the next bin

It will also cap the index to be inside the valid grid range

Returns a tuple with the bin index as first element and the weight fraction inside the bin as second element

Implements MagneticFieldComponent.

Definition at line 89 of file MagneticFieldComponent3D.cc.

  {
    using std::get;

    auto getIndexWeight = [this](double value, int coordinate) -> std::tuple<unsigned int, double> {
      double weight = value * m_invgridPitch[coordinate];
      auto index = static_cast<unsigned int>(weight);
      index = std::min(index, static_cast<unsigned int>(m_mapSize[coordinate] - 2));
      weight -= index;
      return std::make_tuple(index, weight);
    };
 
    const double z = pos.Z();
    const double r2 = pos.Perp2();
 
    // Calculate the lower index of the point in the Z grid
    // Note that z coordinate is inverted to match ANSYS frame
    const auto iz = getIndexWeight(m_maxZ - z, 2);
 
    // directly on z axis: get B-field values from map in cartesian system assuming phi=0, so Bx = Br and By = Bphi
    if (r2 == 0) return interpolate(0, 0, get<0>(iz), 0, 0, get<1>(iz));
 
    const double r = std::sqrt(r2);
    const auto ir = getIndexWeight(r - m_minR, 0);
 
    // Calculate the lower index of the point in the Phi grid
    const double ay = std::abs(pos.Y());
    const auto iphi = getIndexWeight(fast_atan2_minimax<4>(ay, pos.X()), 1);
 
    // Get B-field values from map in cylindrical coordinates
    ROOT::Math::XYZVector b = interpolate(get<0>(ir), get<0>(iphi), get<0>(iz), get<1>(ir), get<1>(iphi), get<1>(iz));
    // and convert it to cartesian
    const double norm = 1 / r;
    const double s = ay * norm;
    const double c = pos.X() * norm;
    // Flip sign of By if y<0
    const double sgny = (pos.Y() >= 0) - (pos.Y() < 0);
    // in cartesian system
    return ROOT::Math::XYZVector(-(b.X() * c - b.Y() * s), -sgny * (b.X() * s + b.Y() * c), b.Z());
  }

GetInstancePtr()

BFieldComponentBeamline ** GetInstancePtr

(

)

Static function holding the instance.

Definition at line 690 of file BFieldComponentBeamline.cc.

  {
    static BFieldComponentBeamline* gInstance = nullptr;
    return &gInstance;
  }

initialize()

void initialize ( )

overridevirtual

Initializes the magnetic field component.

This method opens the magnetic field map file.

Reimplemented from BFieldComponentAbs.

Definition at line 636 of file BFieldComponentBeamline.cc.

  {
    if (!m_ler) m_ler = new BeamlineFieldMapInterpolation;
    if (!m_her) m_her = new BeamlineFieldMapInterpolation;
    m_ler->init(m_mapFilename_ler, m_interFilename_ler, m_mapRegionR[1]);
    m_her->init(m_mapFilename_her, m_interFilename_her, m_mapRegionR[1]);
  }

Instance()

BFieldComponentBeamline & Instance ( )

static

BFieldComponentBeamline instance.

static function

Returns

reference to the BFieldComponentBeamline instance

Definition at line 697 of file BFieldComponentBeamline.cc.

  {
    auto gInstance = GetInstancePtr();
    if (*gInstance == nullptr) {
      // Constructor creates a new instance, inits gInstance.
      new BFieldComponentBeamline();
    }
    return **gInstance;
  }

interpolate()

ROOT::Math::XYZVector interpolate ( unsigned int ir, unsigned int iphi, unsigned int iz, double wr, double wphi, double wz ) const

private

Linear interpolate the magnetic field inside a bin.

Parameters

ir	number of the bin in r
iphi	number of the bin in phi
iz	number of the bin in z
wr	r weight: fraction we are away from the lower r corner relative to the pitch size
wphi	phi weight: fraction we are away from the lower phi corner relative to the pitch size
wz	phi weight: fraction we are away from the lower z corner relative to the pitch size

Definition at line 143 of file MagneticFieldComponent3D.cc.

  {
    const unsigned int strideZ = m_mapSize[0] * m_mapSize[1];
    const unsigned int strideR = m_mapSize[1];
 
    const double wz0 = 1 - wz1;
    const double wr0 = 1 - wr1;
    const double wphi0 = 1 - wphi1;
    const unsigned int j000 = iz * strideZ + ir * strideR + iphi;
    const unsigned int j001 = j000 + 1;
    const unsigned int j010 = j000 + strideR;
    const unsigned int j011 = j001 + strideR;
    const unsigned int j100 = j000 + strideZ;
    const unsigned int j101 = j001 + strideZ;
    const unsigned int j110 = j010 + strideZ;
    const unsigned int j111 = j011 + strideZ;
    const double w00 = wphi0 * wr0;
    const double w10 = wphi0 * wr1;
    const double w01 = wphi1 * wr0;
    const double w11 = wphi1 * wr1;
    const std::vector<ROOT::Math::XYZVector>& B = m_bmap;
    return
      (B[j000] * w00 + B[j001] * w01 + B[j010] * w10 + B[j011] * w11) * wz0 +
      (B[j100] * w00 + B[j101] * w01 + B[j110] * w10 + B[j111] * w11) * wz1;
  }

isInRange()

bool isInRange

(

const ROOT::Math::XYZVector &

point

)

const

Check presence of beamline field at the specific space point in the detector coordinate frame.

Parameters

point

The space point in Cartesian coordinates (x,y,z) in [cm] at which the magnetic field presence is checked

Returns

true is in case of the magnetic field false – otherwise

Definition at line 650 of file BFieldComponentBeamline.cc.

  {
    if (!m_ler || !m_her) return false;
    double s = m_sinBeamCrossAngle, c = m_cosBeamCrossAngle;
    ROOT::Math::XYZVector v = -p; // invert coordinates to match ANSYS one
    double xc = v.X() * c, zs = v.Z() * s, zc = v.Z() * c, xs = v.X() * s;
    ROOT::Math::XYZVector hv{xc - zs, v.Y(), zc + xs};
    ROOT::Math::XYZVector lv{xc + zs, v.Y(), zc - xs};
    return m_ler->inRange(lv) || m_her->inRange(hv);
  }

operator*()

BFieldComponentRadial::BFieldPoint operator* ( const BFieldComponentRadial::BFieldPoint & v, double a )

inline

multiply a radial bfield point by a real number

Definition at line 72 of file BFieldComponentRadial.cc.

  {
    return {v.r * a, v.z * a};
  }

operator+()

BFieldComponentRadial::BFieldPoint operator+ ( const BFieldComponentRadial::BFieldPoint & u, const BFieldComponentRadial::BFieldPoint & v )

inline

Add two radial bfield points together.

Definition at line 78 of file BFieldComponentRadial.cc.

  {
    return {u.r + v.r, u.z + v.z};
  }

terminate()

void terminate ( )

overridevirtual

Terminates the magnetic field component.

This method closes the magnetic field map file.

Reimplemented from BFieldComponentAbs.

Definition at line 685 of file BFieldComponentBeamline.cc.

  {
  }

~BFieldComponentBeamline()

~BFieldComponentBeamline ( )

virtual

The BFieldComponentBeamline destructor.

Definition at line 644 of file BFieldComponentBeamline.cc.

  {
    if (m_ler) delete m_ler;
    if (m_her) delete m_her;
  }