DMagneticFieldStepper class. More...

#include <DMagneticFieldStepper.h>

Public Member Functions
	DMagneticFieldStepper (const DMagneticFieldMap *map, double q=1.0)

	DMagneticFieldStepper (const DMagneticFieldMap map, double q, const DVector3 x, const DVector3 *p)

	~DMagneticFieldStepper ()

jerror_t	SetStartingParams (double q, const DVector3 x, const DVector3 p)

jerror_t	SetMagneticFieldMap (const DMagneticFieldMap *map)

jerror_t	SetStepSize (double step)

void	SetCharge (double q)

double	Step (DVector3 newpos=NULL, DVector3 B=NULL, double stepsize=0.0)

double	FastStep (double stepsize=0.0)

void	GetDirs (DVector3 &xdir, DVector3 &ydir, DVector3 &zdir)

void	GetBField (DVector3 &B)

void	GetMomentum (DVector3 &mom)

void	GetPosition (DVector3 &pos)

double	GetCharge (void)

void	GetPosMom (DVector3 &pos, DVector3 &mom)

bool	SwimToPlane (DVector3 &pos, DVector3 &mom, const DVector3 &origin, const DVector3 &norm, double *pathlen=NULL)

bool	DistToPlane (DVector3 &pos, const DVector3 &origin, const DVector3 &norm)

bool	SwimToRadius (DVector3 &pos, DVector3 &mom, double R, double *pathlen=NULL)

bool	DistToRadius (DVector3 &pos, double R)

double	GetRo (void)

double	Getdz_dphi (void)

double	GetStepSize (void) const

bool	SwimToPOCAtoBeamLine (double q, DVector3 &pos, DVector3 &mom)

Private Member Functions
void	CalcDirs (double *Bvals=NULL)

Private Attributes
const DMagneticFieldMap *	bfield
	pointer to magnetic field map More...

double	stepsize
	maximum distance(cm) to move particle when Step() is called More...

double	last_stepsize
	stepsize (cm) used for last step More...

double	q
	electric charge in units of e More...

DVector3	pos
	current position of particle More...

DVector3	mom
	current location of particle More...

DVector3	start_pos
	starting position of track More...

DVector3	start_mom
	starting momentum of track More...

DVector3	B

double	Ro

double	Rp

double	cos_theta

double	sin_theta

DVector3	xdir

DVector3	ydir

DVector3	zdir

Detailed Description

DMagneticFieldStepper class.

This class will step a particle track through a magnetic field. It has methods to find the point on the track which comes closest to a specified point in space.

Definition at line 22 of file DMagneticFieldStepper.h.

Constructor & Destructor Documentation

DMagneticFieldStepper::DMagneticFieldStepper	(	const DMagneticFieldMap *	map,
		double	q = `1.0`
	)

Definition at line 18 of file DMagneticFieldStepper.cc.

DMagneticFieldStepper::DMagneticFieldStepper	(	const DMagneticFieldMap *	map,
		double	q,
		const DVector3 *	x,
		const DVector3 *	p
	)

Definition at line 31 of file DMagneticFieldStepper.cc.

References x.

DMagneticFieldStepper::~DMagneticFieldStepper ( )

Definition at line 44 of file DMagneticFieldStepper.cc.

Member Function Documentation

void DMagneticFieldStepper::CalcDirs ( double * Bvals = NULL )

private

Calculate the directions of the "natural coordinates" (aka reference trajectory coordinate system) in the lab frame using the current momentum and magnetic field at the current position. The results are left in the private member fields, copies of which may be obtained by a subsequent call to the GetDirs(...) and GetRo() methods.

Definition at line 87 of file DMagneticFieldStepper.cc.

References qBr2p.

bool DMagneticFieldStepper::DistToPlane	(	DVector3 &	pos,
		const DVector3 &	origin,
		const DVector3 &	norm
	)

Definition at line 517 of file DMagneticFieldStepper.cc.

bool DMagneticFieldStepper::DistToRadius	(	DVector3 &	pos,
		double	R
	)

Definition at line 710 of file DMagneticFieldStepper.cc.

double DMagneticFieldStepper::FastStep ( double stepsize = 0.0 )

Definition at line 160 of file DMagneticFieldStepper.cc.

References py, x, and y.

Referenced by DReferenceTrajectory::FastSwim(), and DReferenceTrajectory::FastSwimForHitSelection().

void DMagneticFieldStepper::GetBField ( DVector3 & B )

inline

Definition at line 38 of file DMagneticFieldStepper.h.

References B.

Referenced by DReferenceTrajectory::FastSwim(), DReferenceTrajectory::FastSwimForHitSelection(), and DReferenceTrajectory::Swim().

double DMagneticFieldStepper::GetCharge ( void )

inline

Definition at line 41 of file DMagneticFieldStepper.h.

References q.

void DMagneticFieldStepper::GetDirs	(	DVector3 &	xdir,
		DVector3 &	ydir,
		DVector3 &	zdir
	)

Definition at line 348 of file DMagneticFieldStepper.cc.

Referenced by DReferenceTrajectory::FastSwim(), DReferenceTrajectory::FastSwimForHitSelection(), and DReferenceTrajectory::Swim().

double DMagneticFieldStepper::Getdz_dphi ( void )

inline

Definition at line 49 of file DMagneticFieldStepper.h.

References mom, Ro, ydir, and zdir.

void DMagneticFieldStepper::GetMomentum ( DVector3 & mom )

inline

Definition at line 39 of file DMagneticFieldStepper.h.

References mom.

Referenced by DReferenceTrajectory::BrentsAlgorithm(), DReferenceTrajectory::FindPOCAtoLine(), and DReferenceTrajectory::IntersectTracks().

void DMagneticFieldStepper::GetPosition ( DVector3 & pos )

inline

Definition at line 40 of file DMagneticFieldStepper.h.

References pos.

void DMagneticFieldStepper::GetPosMom	(	DVector3 &	pos,
		DVector3 &	mom
	)

inline

Definition at line 42 of file DMagneticFieldStepper.h.

References mom, and pos.

Referenced by DReferenceTrajectory::FastSwim(), DReferenceTrajectory::FastSwimForHitSelection(), and DReferenceTrajectory::Swim().

double DMagneticFieldStepper::GetRo ( void )

inline

Definition at line 48 of file DMagneticFieldStepper.h.

References Ro.

Referenced by DReferenceTrajectory::FastSwim(), DReferenceTrajectory::FastSwimForHitSelection(), and DReferenceTrajectory::Swim().

double DMagneticFieldStepper::GetStepSize ( void ) const

inline

Definition at line 50 of file DMagneticFieldStepper.h.

References stepsize.

void DMagneticFieldStepper::SetCharge ( double q )

inline

Definition at line 33 of file DMagneticFieldStepper.h.

References q.

Referenced by DTrackCandidate_factory_FDCCathodes::GetTrackMatch().

jerror_t DMagneticFieldStepper::SetMagneticFieldMap ( const DMagneticFieldMap * map )

Definition at line 66 of file DMagneticFieldStepper.cc.

jerror_t DMagneticFieldStepper::SetStartingParams	(	double	q,
		const DVector3 *	x,
		const DVector3 *	p
	)

Definition at line 52 of file DMagneticFieldStepper.cc.

References x.

Referenced by DReferenceTrajectory::FastSwim(), DReferenceTrajectory::FastSwimForHitSelection(), and DReferenceTrajectory::Swim().

jerror_t DMagneticFieldStepper::SetStepSize ( double step )

Definition at line 76 of file DMagneticFieldStepper.cc.

Referenced by DTrackCandidate_factory_FDCCathodes::brun(), DReferenceTrajectory::FastSwim(), DReferenceTrajectory::FastSwimForHitSelection(), and DReferenceTrajectory::Swim().

double DMagneticFieldStepper::Step	(	DVector3 *	newpos = `NULL`,
		DVector3 *	B = `NULL`,
		double	stepsize = `0.0`
	)

Definition at line 197 of file DMagneticFieldStepper.cc.

References grkuta_().

Referenced by DReferenceTrajectory::BrentsAlgorithm(), DReferenceTrajectory::FastSwim(), DReferenceTrajectory::FindPOCAtoLine(), DReferenceTrajectory::IntersectTracks(), and DReferenceTrajectory::Swim().

bool DMagneticFieldStepper::SwimToPlane	(	DVector3 &	pos,
		DVector3 &	mom,
		const DVector3 &	origin,
		const DVector3 &	norm,
		double *	pathlen = `NULL`
	)

Swim the particle from the given position/momentum to the plane defined by origin and norm. "origin" should define a point somewhere in the plane and norm a vector normal to the plane. The charge of the particle is set by the constructor or last call to SetStartingParameters(...).

If a non-NULL value is passed for pathlen then the pathlength of the track from the given starting position to the intersection point is given.

THE FOLLOWING FEATURE IS CURRENTLY DISABLED! Note that a check is made that the particle is initially going toward the plane. If the particle appears to be going away from the plane, then the momentum is temporarily flipped as well as the charge so that the particle is swum backwards.

Particles will only be swum a distance of MAX_SWIM_DIST (currently hardwired to 20 meters) along their trajectory before returning boolean true indicating failure to intersect the plane.

On success, a value of false is returned and the values in pos and mom will be updated with the position and momentum at the point of intersection with the plane.

Definition at line 358 of file DMagneticFieldStepper.cc.

References alpha, MAX_SWIM_DIST, and sqrt().

Referenced by DTrackCandidate_factory_FDCCathodes::GetTrackMatch().

bool DMagneticFieldStepper::SwimToPOCAtoBeamLine	(	double	q,
		DVector3 &	pos,
		DVector3 &	mom
	)

Routine to find the position-of-closest approach of a trajectory to the beam line. Upon entry, q, pos, and mom contain a point on a track pointing away from the beamline. (Beamline is assumed to be along z at x=y=0). At return, the pos and mom vectors will contain the position and momentum at the POCA. Upon success, a boolean "false" is returned. If the routine fails, then a boolean "true" is returned and the values of pos and mom are left to what they were upon entry.

Definition at line 526 of file DMagneticFieldStepper.cc.

bool DMagneticFieldStepper::SwimToRadius	(	DVector3 &	pos,
		DVector3 &	mom,
		double	R,
		double *	pathlen = `NULL`
	)

Swim the particle from the point specified by the given position and momentum until it crosses the specified radius R as measured from the beamline.

If a non-NULL value is passed for pathlen then the pathlength of the track from the given starting position to the intersection point is given.

Particles will only be swum a distance of MAX_SWIM_DIST (currently hardwired to 20 meters) along their trajectory before returning boolean true indicating failure to intersect the radius. This can happen if the particle's momentum is too low to reach the radius.

On success, a value of false is returned and the values in pos and mom will be updated with the position and momentum at the point of intersection with the radius.

Definition at line 626 of file DMagneticFieldStepper.cc.

References alpha, MAX_SWIM_DIST, and sqrt().

Member Data Documentation

DVector3 DMagneticFieldStepper::B

private

Definition at line 63 of file DMagneticFieldStepper.h.

Referenced by GetBField().

const DMagneticFieldMap* DMagneticFieldStepper::bfield

private

pointer to magnetic field map

Definition at line 55 of file DMagneticFieldStepper.h.

double DMagneticFieldStepper::cos_theta

private

Definition at line 65 of file DMagneticFieldStepper.h.

double DMagneticFieldStepper::last_stepsize

private

stepsize (cm) used for last step

Definition at line 57 of file DMagneticFieldStepper.h.

DVector3 DMagneticFieldStepper::mom

private

current location of particle

Definition at line 60 of file DMagneticFieldStepper.h.

Referenced by Getdz_dphi(), GetMomentum(), and GetPosMom().

DVector3 DMagneticFieldStepper::pos

private

current position of particle

Definition at line 59 of file DMagneticFieldStepper.h.

Referenced by GetPosition(), and GetPosMom().

double DMagneticFieldStepper::q

private

electric charge in units of e

Definition at line 58 of file DMagneticFieldStepper.h.

Referenced by GetCharge(), and SetCharge().

double DMagneticFieldStepper::Ro

private

Definition at line 64 of file DMagneticFieldStepper.h.

Referenced by Getdz_dphi(), and GetRo().

double DMagneticFieldStepper::Rp

private

Definition at line 64 of file DMagneticFieldStepper.h.

double DMagneticFieldStepper::sin_theta

private

Definition at line 65 of file DMagneticFieldStepper.h.

DVector3 DMagneticFieldStepper::start_mom

private

starting momentum of track

Definition at line 62 of file DMagneticFieldStepper.h.

DVector3 DMagneticFieldStepper::start_pos

private

starting position of track

Definition at line 61 of file DMagneticFieldStepper.h.

double DMagneticFieldStepper::stepsize

private

maximum distance(cm) to move particle when Step() is called

Definition at line 56 of file DMagneticFieldStepper.h.

Referenced by GetStepSize().

DVector3 DMagneticFieldStepper::xdir

private

Definition at line 67 of file DMagneticFieldStepper.h.

DVector3 DMagneticFieldStepper::ydir

private

Definition at line 67 of file DMagneticFieldStepper.h.

Referenced by Getdz_dphi().

DVector3 DMagneticFieldStepper::zdir

private

Definition at line 67 of file DMagneticFieldStepper.h.

Referenced by Getdz_dphi().

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

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation