THelix has two different constructors.

If a particle with charge q passes through a point (x,y,z) with momentum (px,py,pz) with magnetic field B along an axis (nx,ny,nz), this helix can be constructed like:

THelix p(x,y,z, px,py,pz, q*B, nx,ny,nz);

(nx,ny,nz) defaults to (0,0,1).

A helix in its own frame can be defined with a pivotal point (x0,y0,z0), the velocity at that point (vx0,vy0,vz0), and an angular frequency w. Combining vx0 and vy0 to a transverse velocity vt0 one can parametrize the helix as:

x(t) = x0 - vt0 / w * sin(-w * t + phi0)
y(t) = y0 + vt0 / w * cos(-w * t + phi0)
z(t) = z0 + vz0 * t

The second constructor has 6 parameters,

Example:

THelix pl1(xyz, v, w, range, rtype, axis);

where:

xyz : array of initial position
v : array of initial velocity
w : angular frequency
range: helix range
rtype: kHelixZ specifies allowed drawing range in helix Z direction, i.e., along B field. kLabZ specifies drawing range in lab frame. kHelixX, kHelixY, kLabX, kLabY, kUnchanged ... etc can also be specified
axis : helix axis

Example constructing a helix with several default values and drawing it:

{
   TCanvas* helix_example_c1 = new TCanvas("helix_example_c1");
   TView *view = TView::CreateView(1);
   view->SetRange(-1,-1,-1,1,1,1);
   THelix *helix = new THelix(0., 0., 0., 1., 0., 0.3, 10.);
   helix->Draw();
}

This initializes a helix with its axis in Z direction (rtype=kHelixZ).

Definition at line 36 of file THelix.h.

Public Member Functions
	THelix ()
	Helix default constructor. More...

	THelix (Double_t x, Double_t y, Double_t z, Double_t vx, Double_t vy, Double_t vz, Double_t w)
	Helix normal constructor. More...

	THelix (Double_t xyz, Double_t v, Double_t w, Double_t range=0, EHelixRangeType rtype=kHelixZ, Double_t axis=0)
	Helix normal constructor. More...

	THelix (const THelix &helix)
	Helix copy constructor. More...

virtual	~THelix ()
	Helix destructor. More...

virtual void	Copy (TObject &helix) const
	Copy this helix to obj. More...

virtual void	Draw (Option_t *option="")
	Draw this helix with its current attributes. More...

Option_t *	GetOption () const

virtual void	Print (Option_t *option="") const
	Dump this helix with its attributes. More...

virtual void	SavePrimitive (std::ostream &out, Option_t *option="")
	Save primitive as a C++ statement(s) on output stream out. More...

virtual void	SetAxis (Double_t *axis)
	Set a new axis for the helix. This will make a new rotation matrix. More...

virtual void	SetAxis (Double_t x, Double_t y, Double_t z)
	Set axis. More...

void	SetHelix (Double_t xyz, Double_t v, Double_t w, Double_t range=0, EHelixRangeType type=kUnchanged, Double_t axis=0)
	Set all helix parameters. More...

virtual void	SetOption (Option_t *option="")

virtual void	SetRange (Double_t *range, EHelixRangeType rtype=kHelixZ)
	Set a new range for the helix. This will remake the polyline. More...

virtual void	SetRange (Double_t r1, Double_t r2, EHelixRangeType rtype=kHelixZ)
	Set range. More...

Public Member Functions inherited from TPolyLine3D
	TPolyLine3D ()
	3-D polyline default constructor. More...

	TPolyLine3D (Int_t n, Option_t *option="")
	3-D polyline normal constructor with initialization to 0. More...

	TPolyLine3D (Int_t n, Float_t p, Option_t option="")
	3-D polyline normal constructor. More...

	TPolyLine3D (Int_t n, Double_t p, Option_t option="")
	3-D polyline normal constructor. More...

	TPolyLine3D (Int_t n, Float_t x, Float_t y, Float_t z, Option_t option="")
	3-D polyline normal constructor. More...

	TPolyLine3D (Int_t n, Double_t x, Double_t y, Double_t z, Option_t option="")
	3-D polyline normal constructor. More...

	TPolyLine3D (const TPolyLine3D &polylin)
	3-D polyline copy ctor. More...

virtual	~TPolyLine3D ()
	3-D polyline destructor. More...

virtual Int_t	DistancetoPrimitive (Int_t px, Int_t py)
	Compute distance from point px,py to a 3-D polyline. More...

virtual void	DrawPolyLine (Int_t n, Float_t p, Option_t option="")
	Draw 3-D polyline with new coordinates. More...

virtual void	ExecuteEvent (Int_t event, Int_t px, Int_t py)
	Execute action corresponding to one event. More...

Int_t	GetLastPoint () const

Int_t	GetN () const

Option_t *	GetOption () const

Float_t *	GetP () const

virtual void	ls (Option_t *option="") const
	List this 3-D polyline. More...

virtual Int_t	Merge (TCollection *list)
	Merge polylines in the collection in this polyline. More...

TPolyLine3D &	operator= (const TPolyLine3D &polylin)
	assignment operator More...

virtual void	Paint (Option_t *option="")
	Paint a TPolyLine3D. More...

virtual Int_t	SetNextPoint (Double_t x, Double_t y, Double_t z)
	Set point following LastPoint to x, y, z. More...

virtual void	SetPoint (Int_t point, Double_t x, Double_t y, Double_t z)
	Set point n to x, y, z. More...

virtual void	SetPolyLine (Int_t n, Option_t *option="")
	Re-initialize polyline with n points (0,0,0). More...

virtual void	SetPolyLine (Int_t n, Float_t p, Option_t option="")
	Re-initialize polyline with n points from p. More...

virtual void	SetPolyLine (Int_t n, Double_t p, Option_t option="")
	Re-initialize polyline with n points from p. More...

virtual Int_t	Size () const

Public Member Functions inherited from TObject
	TObject ()
	TObject constructor. More...

	TObject (const TObject &object)
	TObject copy ctor. More...

virtual	~TObject ()
	TObject destructor. More...

void	AbstractMethod (const char *method) const
	Use this method to implement an "abstract" method that you don't want to leave purely abstract. More...

virtual void	AppendPad (Option_t *option="")
	Append graphics object to current pad. More...

virtual void	Browse (TBrowser *b)
	Browse object. May be overridden for another default action. More...

ULong_t	CheckedHash ()
	Checked and record whether for this class has a consistent Hash/RecursiveRemove setup (*) and then return the regular Hash value for this object. More...

virtual const char *	ClassName () const
	Returns name of class to which the object belongs. More...

virtual void	Clear (Option_t *="")

virtual TObject *	Clone (const char *newname="") const
	Make a clone of an object using the Streamer facility. More...

virtual Int_t	Compare (const TObject *obj) const
	Compare abstract method. More...

virtual void	Delete (Option_t *option="")
	Delete this object. More...

virtual void	DrawClass () const
	Draw class inheritance tree of the class to which this object belongs. More...

virtual TObject *	DrawClone (Option_t *option="") const
	Draw a clone of this object in the current selected pad for instance with: `gROOT->SetSelectedPad(gPad)`. More...

virtual void	Dump () const
	Dump contents of object on stdout. More...

virtual void	Error (const char method, const char msgfmt,...) const
	Issue error message. More...

virtual void	Execute (const char method, const char params, Int_t *error=0)
	Execute method on this object with the given parameter string, e.g. More...

virtual void	Execute (TMethod method, TObjArray params, Int_t *error=0)
	Execute method on this object with parameters stored in the TObjArray. More...

virtual void	Fatal (const char method, const char msgfmt,...) const
	Issue fatal error message. More...

virtual TObject *	FindObject (const char *name) const
	Must be redefined in derived classes. More...

virtual TObject *	FindObject (const TObject *obj) const
	Must be redefined in derived classes. More...

virtual Option_t *	GetDrawOption () const
	Get option used by the graphics system to draw this object. More...

virtual const char *	GetIconName () const
	Returns mime type name of object. More...

virtual const char *	GetName () const
	Returns name of object. More...

virtual char *	GetObjectInfo (Int_t px, Int_t py) const
	Returns string containing info about the object at position (px,py). More...

virtual const char *	GetTitle () const
	Returns title of object. More...

virtual UInt_t	GetUniqueID () const
	Return the unique object id. More...

virtual Bool_t	HandleTimer (TTimer *timer)
	Execute action in response of a timer timing out. More...

virtual ULong_t	Hash () const
	Return hash value for this object. More...

Bool_t	HasInconsistentHash () const
	Return true is the type of this object is known to have an inconsistent setup for Hash and RecursiveRemove (i.e. More...

virtual void	Info (const char method, const char msgfmt,...) const
	Issue info message. More...

virtual Bool_t	InheritsFrom (const char *classname) const
	Returns kTRUE if object inherits from class "classname". More...

virtual Bool_t	InheritsFrom (const TClass *cl) const
	Returns kTRUE if object inherits from TClass cl. More...

virtual void	Inspect () const
	Dump contents of this object in a graphics canvas. More...

void	InvertBit (UInt_t f)

virtual Bool_t	IsEqual (const TObject *obj) const
	Default equal comparison (objects are equal if they have the same address in memory). More...

virtual Bool_t	IsFolder () const
	Returns kTRUE in case object contains browsable objects (like containers or lists of other objects). More...

R__ALWAYS_INLINE Bool_t	IsOnHeap () const

virtual Bool_t	IsSortable () const

R__ALWAYS_INLINE Bool_t	IsZombie () const

void	MayNotUse (const char *method) const
	Use this method to signal that a method (defined in a base class) may not be called in a derived class (in principle against good design since a child class should not provide less functionality than its parent, however, sometimes it is necessary). More...

virtual Bool_t	Notify ()
	This method must be overridden to handle object notification. More...

void	Obsolete (const char method, const char asOfVers, const char *removedFromVers) const
	Use this method to declare a method obsolete. More...

void	operator delete (void *ptr)
	Operator delete. More...

void	operator delete[] (void *ptr)
	Operator delete []. More...

void *	operator new (size_t sz)

void *	operator new (size_t sz, void *vp)

void *	operator new[] (size_t sz)

void *	operator new[] (size_t sz, void *vp)

TObject &	operator= (const TObject &rhs)
	TObject assignment operator. More...

virtual void	Pop ()
	Pop on object drawn in a pad to the top of the display list. More...

virtual Int_t	Read (const char *name)
	Read contents of object with specified name from the current directory. More...

virtual void	RecursiveRemove (TObject *obj)
	Recursively remove this object from a list. More...

void	ResetBit (UInt_t f)

virtual void	SaveAs (const char filename="", Option_t option="") const
	Save this object in the file specified by filename. More...

void	SetBit (UInt_t f, Bool_t set)
	Set or unset the user status bits as specified in f. More...

void	SetBit (UInt_t f)

virtual void	SetDrawOption (Option_t *option="")
	Set drawing option for object. More...

virtual void	SetUniqueID (UInt_t uid)
	Set the unique object id. More...

virtual void	SysError (const char method, const char msgfmt,...) const
	Issue system error message. More...

R__ALWAYS_INLINE Bool_t	TestBit (UInt_t f) const

Int_t	TestBits (UInt_t f) const

virtual void	UseCurrentStyle ()
	Set current style settings in this object This function is called when either TCanvas::UseCurrentStyle or TROOT::ForceStyle have been invoked. More...

virtual void	Warning (const char method, const char msgfmt,...) const
	Issue warning message. More...

virtual Int_t	Write (const char *name=0, Int_t option=0, Int_t bufsize=0)
	Write this object to the current directory. More...

virtual Int_t	Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const
	Write this object to the current directory. More...

Public Member Functions inherited from TAttLine
	TAttLine ()
	AttLine default constructor. More...

	TAttLine (Color_t lcolor, Style_t lstyle, Width_t lwidth)
	AttLine normal constructor. More...

virtual	~TAttLine ()
	AttLine destructor. More...

void	Copy (TAttLine &attline) const
	Copy this line attributes to a new TAttLine. More...

Int_t	DistancetoLine (Int_t px, Int_t py, Double_t xp1, Double_t yp1, Double_t xp2, Double_t yp2)
	Compute distance from point px,py to a line. More...

virtual Color_t	GetLineColor () const
	Return the line color. More...

virtual Style_t	GetLineStyle () const
	Return the line style. More...

virtual Width_t	GetLineWidth () const
	Return the line width. More...

virtual void	Modify ()
	Change current line attributes if necessary. More...

virtual void	ResetAttLine (Option_t *option="")
	Reset this line attributes to default values. More...

virtual void	SaveLineAttributes (std::ostream &out, const char *name, Int_t coldef=1, Int_t stydef=1, Int_t widdef=1)
	Save line attributes as C++ statement(s) on output stream out. More...

virtual void	SetLineAttributes ()
	Invoke the DialogCanvas Line attributes. More...

virtual void	SetLineColor (Color_t lcolor)
	Set the line color. More...

virtual void	SetLineColorAlpha (Color_t lcolor, Float_t lalpha)
	Set a transparent line color. More...

virtual void	SetLineStyle (Style_t lstyle)
	Set the line style. More...

virtual void	SetLineWidth (Width_t lwidth)
	Set the line width. More...

Public Member Functions inherited from TAtt3D
	TAtt3D ()

virtual	~TAtt3D ()

virtual void	Sizeof3D () const
	Set total size of this 3D object (used by X3D interface). More...

Protected Member Functions
Double_t	FindClosestPhase (Double_t phi0, Double_t cosine)
	Finds the closest phase to phi0 that gives cos(phase) = cosine. More...

THelix &	operator= (const THelix &)
	assignment operator More...

void	SetRotMatrix ()
	Set the rotational matrix according to the helix axis. More...

Protected Member Functions inherited from TObject
virtual void	DoError (int level, const char location, const char fmt, va_list va) const
	Interface to ErrorHandler (protected). More...

void	MakeZombie ()

Protected Attributes
Double_t	fAxis [3]

Double_t	fPhi0

Double_t	fRange [2]

TRotMatrix *	fRotMat

Double_t	fVt

Double_t	fVz

Double_t	fW

Double_t	fX0

Double_t	fY0

Double_t	fZ0

Protected Attributes inherited from TPolyLine3D
Int_t	fLastPoint
	The index of the last filled point. More...

Int_t	fN
	Number of points. More...

TString	fOption
	options More...

Float_t *	fP
	[3*fN] Array of 3-D coordinates (x,y,z) More...

Protected Attributes inherited from TAttLine
Color_t	fLineColor
	Line color. More...

Style_t	fLineStyle
	Line style. More...

Width_t	fLineWidth
	Line width. More...

Static Protected Attributes
static Int_t	fgMinNSeg =5

Additional Inherited Members
Public Types inherited from TObject
enum	{ kIsOnHeap = 0x01000000, kNotDeleted = 0x02000000, kZombie = 0x04000000, kInconsistent = 0x08000000, kBitMask = 0x00ffffff }

enum	{ kSingleKey = BIT(0), kOverwrite = BIT(1), kWriteDelete = BIT(2) }

enum	EDeprecatedStatusBits { kObjInCanvas = BIT(3) }

enum	EStatusBits { kCanDelete = BIT(0), kMustCleanup = BIT(3), kIsReferenced = BIT(4), kHasUUID = BIT(5), kCannotPick = BIT(6), kNoContextMenu = BIT(8), kInvalidObject = BIT(13) }

Static Public Member Functions inherited from TPolyLine3D
static void	DrawOutlineCube (TList outline, Double_t rmin, Double_t *rmax)
	Draw cube outline with 3d polylines. More...

Static Public Member Functions inherited from TObject
static Long_t	GetDtorOnly ()
	Return destructor only flag. More...

static Bool_t	GetObjectStat ()
	Get status of object stat flag. More...

static void	SetDtorOnly (void *obj)
	Set destructor only flag. More...

static void	SetObjectStat (Bool_t stat)
	Turn on/off tracking of objects in the TObjectTable. More...

#include <THelix.h>

Inheritance diagram for THelix:

[legend]

Constructor & Destructor Documentation

◆ THelix() [1/4]

THelix::THelix ( )

Helix default constructor.

Definition at line 122 of file THelix.cxx.

◆ THelix() [2/4]

THelix::THelix	(	Double_t	x,
		Double_t	y,
		Double_t	z,
		Double_t	vx,
		Double_t	vy,
		Double_t	vz,
		Double_t	w
	)

Helix normal constructor.

Definition at line 135 of file THelix.cxx.

◆ THelix() [3/4]

THelix::THelix	(	Double_t *	xyz,
		Double_t *	v,
		Double_t	w,
		Double_t *	range = `0`,
		EHelixRangeType	rtype = `kHelixZ`,
		Double_t *	axis = `0`
	)

Helix normal constructor.

Definition at line 157 of file THelix.cxx.

◆ THelix() [4/4]

THelix::THelix ( const THelix & helix )

Helix copy constructor.

Definition at line 236 of file THelix.cxx.

◆ ~THelix()

THelix::~THelix ( )

virtual

Helix destructor.

Definition at line 227 of file THelix.cxx.

Member Function Documentation

◆ Copy()

void THelix::Copy ( TObject & helix ) const

virtual

Copy this helix to obj.

Reimplemented from TPolyLine3D.

Definition at line 246 of file THelix.cxx.

◆ Draw()

void THelix::Draw ( Option_t * option = "" )

virtual

Draw this helix with its current attributes.

Reimplemented from TPolyLine3D.

Definition at line 280 of file THelix.cxx.

◆ FindClosestPhase()

Double_t THelix::FindClosestPhase	(	Double_t	phi0,
		Double_t	cosine
	)

protected

Finds the closest phase to phi0 that gives cos(phase) = cosine.

Definition at line 597 of file THelix.cxx.

◆ GetOption()

Option_t* THelix::GetOption ( ) const

inlinevirtual

Reimplemented from TObject.

Definition at line 70 of file THelix.h.

◆ operator=()

THelix & THelix::operator= ( const THelix & hx )

protected

assignment operator

Definition at line 204 of file THelix.cxx.

◆ Print()

void THelix::Print ( Option_t * option = "" ) const

virtual

Dump this helix with its attributes.

Reimplemented from TPolyLine3D.

Definition at line 289 of file THelix.cxx.

◆ SavePrimitive()

void THelix::SavePrimitive	(	std::ostream &	out,
		Option_t *	option = `""`
	)

virtual

Save primitive as a C++ statement(s) on output stream out.

Reimplemented from TPolyLine3D.

Definition at line 298 of file THelix.cxx.

◆ SetAxis() [1/2]

void THelix::SetAxis ( Double_t * axis )

virtual

Set a new axis for the helix. This will make a new rotation matrix.

Definition at line 322 of file THelix.cxx.

◆ SetAxis() [2/2]

void THelix::SetAxis	(	Double_t	x,
		Double_t	y,
		Double_t	z
	)

virtual

Set axis.

Definition at line 347 of file THelix.cxx.

◆ SetHelix()

void THelix::SetHelix	(	Double_t *	xyz,
		Double_t *	v,
		Double_t	w,
		Double_t *	range = `0`,
		EHelixRangeType	type = `kUnchanged`,
		Double_t *	axis = `0`
	)

Set all helix parameters.

Definition at line 84 of file THelix.cxx.

◆ SetOption()

virtual void THelix::SetOption ( Option_t * option = "" )

inlinevirtual

Reimplemented from TPolyLine3D.

Definition at line 73 of file THelix.h.

◆ SetRange() [1/2]

void THelix::SetRange	(	Double_t *	range,
		EHelixRangeType	rtype = `kHelixZ`
	)

virtual

Set a new range for the helix. This will remake the polyline.

Definition at line 357 of file THelix.cxx.

◆ SetRange() [2/2]

void THelix::SetRange	(	Double_t	r1,
		Double_t	r2,
		EHelixRangeType	rtype = `kHelixZ`
	)

virtual

Set range.

Definition at line 550 of file THelix.cxx.

◆ SetRotMatrix()

void THelix::SetRotMatrix ( )

protected

Set the rotational matrix according to the helix axis.

Definition at line 568 of file THelix.cxx.

Member Data Documentation

◆ fAxis

Double_t THelix::fAxis[3]

protected

Definition at line 46 of file THelix.h.

◆ fgMinNSeg

Int_t THelix::fgMinNSeg =5

staticprotected

Definition at line 55 of file THelix.h.

◆ fPhi0

Double_t THelix::fPhi0

protected

Definition at line 43 of file THelix.h.

◆ fRange

Double_t THelix::fRange[2]

protected

Definition at line 48 of file THelix.h.

◆ fRotMat

TRotMatrix* THelix::fRotMat

protected

Definition at line 47 of file THelix.h.

◆ fVt

Double_t THelix::fVt

protected

Definition at line 42 of file THelix.h.

◆ fVz

Double_t THelix::fVz

protected

Definition at line 44 of file THelix.h.

◆ fW

Double_t THelix::fW

protected

Definition at line 45 of file THelix.h.

◆ fX0

Double_t THelix::fX0

protected

Definition at line 39 of file THelix.h.

◆ fY0

Double_t THelix::fY0

protected

Definition at line 40 of file THelix.h.

◆ fZ0

Double_t THelix::fZ0

protected

Definition at line 41 of file THelix.h.

Libraries for THelix:

[legend]

Public Member Functions

Protected Member Functions

Protected Attributes

Static Protected Attributes

Additional Inherited Members

Constructor & Destructor Documentation

◆ THelix() [1/4]

◆ THelix() [2/4]

◆ THelix() [3/4]

◆ THelix() [4/4]

◆ ~THelix()

Member Function Documentation

◆ Copy()

◆ Draw()

◆ FindClosestPhase()

◆ GetOption()

◆ operator=()

◆ Print()

◆ SavePrimitive()

◆ SetAxis() [1/2]

◆ SetAxis() [2/2]

◆ SetHelix()

◆ SetOption()

◆ SetRange() [1/2]

◆ SetRange() [2/2]

◆ SetRotMatrix()

Member Data Documentation

◆ fAxis

◆ fgMinNSeg

◆ fPhi0

◆ fRange

◆ fRotMat

◆ fVt

◆ fVz

◆ fW

◆ fX0

◆ fY0

◆ fZ0