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THelix Class Reference

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).
float * q
THelix has two different constructors.
Definition THelix.h:23
Double_t y[n]
Definition legend1.C:17
Double_t x[n]
Definition legend1.C:17

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
double cos(double)
double sin(double)

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");
view->SetRange(-1,-1,-1,1,1,1);
THelix *helix = new THelix(0., 0., 0., 1., 0., 0.3, 10.);
helix->Draw();
}
The Canvas class.
Definition TCanvas.h:23
virtual void Draw(Option_t *option="")
Draw this helix with its current attributes.
Definition THelix.cxx:279
THelix()
Helix default constructor.
Definition THelix.cxx:121
See TView3D.
Definition TView.h:25
static TView * CreateView(Int_t system=1, const Double_t *rmin=0, const Double_t *rmax=0)
Create a concrete default 3-d view via the plug-in manager.
Definition TView.cxx:27
virtual void SetRange(const Double_t *min, const Double_t *max)=0

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

Definition at line 23 of file THelix.h.

Public Member Functions

 THelix ()
 Helix default constructor.
 
 THelix (const THelix &helix)
 Helix copy constructor.
 
 THelix (Double_t const *xyz, Double_t const *v, Double_t w, Double_t const *range=0, EHelixRangeType rtype=kHelixZ, Double_t const *axis=0)
 Helix normal constructor.
 
 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.
 
virtual ~THelix ()
 Helix destructor.
 
virtual void Copy (TObject &helix) const
 Copy this helix to obj.
 
virtual void Draw (Option_t *option="")
 Draw this helix with its current attributes.
 
Option_tGetOption () const
 
virtual void Print (Option_t *option="") const
 Dump this helix with its attributes.
 
virtual void SavePrimitive (std::ostream &out, Option_t *option="")
 Save primitive as a C++ statement(s) on output stream out.
 
virtual void SetAxis (Double_t const *axis)
 Set a new axis for the helix. This will make a new rotation matrix.
 
virtual void SetAxis (Double_t x, Double_t y, Double_t z)
 Set axis.
 
void SetHelix (Double_t const *xyz, Double_t const *v, Double_t w, Double_t const *range=0, EHelixRangeType type=kUnchanged, Double_t const *axis=0)
 Set all helix parameters.
 
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.
 
virtual void SetRange (Double_t r1, Double_t r2, EHelixRangeType rtype=kHelixZ)
 Set range.
 
- Public Member Functions inherited from TPolyLine3D
 TPolyLine3D ()
 3-D polyline default constructor.
 
 TPolyLine3D (const TPolyLine3D &polylin)
 3-D polyline copy ctor.
 
 TPolyLine3D (Int_t n, Double_t const *p, Option_t *option="")
 3-D polyline normal constructor.
 
 TPolyLine3D (Int_t n, Double_t const *x, Double_t const *y, Double_t const *z, Option_t *option="")
 3-D polyline normal constructor.
 
 TPolyLine3D (Int_t n, Float_t const *p, Option_t *option="")
 3-D polyline normal constructor.
 
 TPolyLine3D (Int_t n, Float_t const *x, Float_t const *y, Float_t const *z, Option_t *option="")
 3-D polyline normal constructor.
 
 TPolyLine3D (Int_t n, Option_t *option="")
 3-D polyline normal constructor with initialization to 0.
 
virtual ~TPolyLine3D ()
 3-D polyline destructor.
 
virtual Int_t DistancetoPrimitive (Int_t px, Int_t py)
 Compute distance from point px,py to a 3-D polyline.
 
virtual void DrawPolyLine (Int_t n, Float_t *p, Option_t *option="")
 Draw 3-D polyline with new coordinates.
 
virtual void ExecuteEvent (Int_t event, Int_t px, Int_t py)
 Execute action corresponding to one event.
 
Int_t GetLastPoint () const
 
Int_t GetN () const
 
Option_tGetOption () const
 
Float_tGetP () const
 
virtual void ls (Option_t *option="") const
 List this 3-D polyline.
 
virtual Int_t Merge (TCollection *list)
 Merge polylines in the collection in this polyline.
 
TPolyLine3Doperator= (const TPolyLine3D &polylin)
 assignment operator
 
virtual void Paint (Option_t *option="")
 Paint a TPolyLine3D.
 
virtual Int_t SetNextPoint (Double_t x, Double_t y, Double_t z)
 Set point following LastPoint to x, y, z.
 
virtual void SetPoint (Int_t point, Double_t x, Double_t y, Double_t z)
 Set point n to x, y, z.
 
virtual void SetPolyLine (Int_t n, Double_t *p, Option_t *option="")
 Re-initialize polyline with n points from p.
 
virtual void SetPolyLine (Int_t n, Float_t *p, Option_t *option="")
 Re-initialize polyline with n points from p.
 
virtual void SetPolyLine (Int_t n, Option_t *option="")
 Re-initialize polyline with n points (0,0,0).
 
virtual Int_t Size () const
 
- Public Member Functions inherited from TObject
 TObject ()
 TObject constructor.
 
 TObject (const TObject &object)
 TObject copy ctor.
 
virtual ~TObject ()
 TObject destructor.
 
void AbstractMethod (const char *method) const
 Use this method to implement an "abstract" method that you don't want to leave purely abstract.
 
virtual void AppendPad (Option_t *option="")
 Append graphics object to current pad.
 
virtual void Browse (TBrowser *b)
 Browse object. May be overridden for another default action.
 
ULong_t CheckedHash ()
 Check and record whether this class has a consistent Hash/RecursiveRemove setup (*) and then return the regular Hash value for this object.
 
virtual const char * ClassName () const
 Returns name of class to which the object belongs.
 
virtual void Clear (Option_t *="")
 
virtual TObjectClone (const char *newname="") const
 Make a clone of an object using the Streamer facility.
 
virtual Int_t Compare (const TObject *obj) const
 Compare abstract method.
 
virtual void Delete (Option_t *option="")
 Delete this object.
 
virtual void DrawClass () const
 Draw class inheritance tree of the class to which this object belongs.
 
virtual TObjectDrawClone (Option_t *option="") const
 Draw a clone of this object in the current selected pad for instance with: gROOT->SetSelectedPad(gPad).
 
virtual void Dump () const
 Dump contents of object on stdout.
 
virtual void Error (const char *method, const char *msgfmt,...) const
 Issue error message.
 
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.
 
virtual void Execute (TMethod *method, TObjArray *params, Int_t *error=0)
 Execute method on this object with parameters stored in the TObjArray.
 
virtual void Fatal (const char *method, const char *msgfmt,...) const
 Issue fatal error message.
 
virtual TObjectFindObject (const char *name) const
 Must be redefined in derived classes.
 
virtual TObjectFindObject (const TObject *obj) const
 Must be redefined in derived classes.
 
virtual Option_tGetDrawOption () const
 Get option used by the graphics system to draw this object.
 
virtual const char * GetIconName () const
 Returns mime type name of object.
 
virtual const char * GetName () const
 Returns name of object.
 
virtual char * GetObjectInfo (Int_t px, Int_t py) const
 Returns string containing info about the object at position (px,py).
 
virtual const char * GetTitle () const
 Returns title of object.
 
virtual UInt_t GetUniqueID () const
 Return the unique object id.
 
virtual Bool_t HandleTimer (TTimer *timer)
 Execute action in response of a timer timing out.
 
virtual ULong_t Hash () const
 Return hash value for this object.
 
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.
 
virtual void Info (const char *method, const char *msgfmt,...) const
 Issue info message.
 
virtual Bool_t InheritsFrom (const char *classname) const
 Returns kTRUE if object inherits from class "classname".
 
virtual Bool_t InheritsFrom (const TClass *cl) const
 Returns kTRUE if object inherits from TClass cl.
 
virtual void Inspect () const
 Dump contents of this object in a graphics canvas.
 
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).
 
virtual Bool_t IsFolder () const
 Returns kTRUE in case object contains browsable objects (like containers or lists of other objects).
 
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).
 
virtual Bool_t Notify ()
 This method must be overridden to handle object notification.
 
void Obsolete (const char *method, const char *asOfVers, const char *removedFromVers) const
 Use this method to declare a method obsolete.
 
void operator delete (void *ptr)
 Operator delete.
 
void operator delete[] (void *ptr)
 Operator delete [].
 
voidoperator new (size_t sz)
 
voidoperator new (size_t sz, void *vp)
 
voidoperator new[] (size_t sz)
 
voidoperator new[] (size_t sz, void *vp)
 
TObjectoperator= (const TObject &rhs)
 TObject assignment operator.
 
virtual void Pop ()
 Pop on object drawn in a pad to the top of the display list.
 
virtual Int_t Read (const char *name)
 Read contents of object with specified name from the current directory.
 
virtual void RecursiveRemove (TObject *obj)
 Recursively remove this object from a list.
 
void ResetBit (UInt_t f)
 
virtual void SaveAs (const char *filename="", Option_t *option="") const
 Save this object in the file specified by filename.
 
void SetBit (UInt_t f)
 
void SetBit (UInt_t f, Bool_t set)
 Set or unset the user status bits as specified in f.
 
virtual void SetDrawOption (Option_t *option="")
 Set drawing option for object.
 
virtual void SetUniqueID (UInt_t uid)
 Set the unique object id.
 
virtual void SysError (const char *method, const char *msgfmt,...) const
 Issue system error message.
 
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.
 
virtual void Warning (const char *method, const char *msgfmt,...) const
 Issue warning message.
 
virtual Int_t Write (const char *name=0, Int_t option=0, Int_t bufsize=0)
 Write this object to the current directory.
 
virtual Int_t Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const
 Write this object to the current directory.
 
- Public Member Functions inherited from TAttLine
 TAttLine ()
 AttLine default constructor.
 
 TAttLine (Color_t lcolor, Style_t lstyle, Width_t lwidth)
 AttLine normal constructor.
 
virtual ~TAttLine ()
 AttLine destructor.
 
void Copy (TAttLine &attline) const
 Copy this line attributes to a new TAttLine.
 
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.
 
virtual Color_t GetLineColor () const
 Return the line color.
 
virtual Style_t GetLineStyle () const
 Return the line style.
 
virtual Width_t GetLineWidth () const
 Return the line width.
 
virtual void Modify ()
 Change current line attributes if necessary.
 
virtual void ResetAttLine (Option_t *option="")
 Reset this line attributes to default values.
 
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.
 
virtual void SetLineAttributes ()
 Invoke the DialogCanvas Line attributes.
 
virtual void SetLineColor (Color_t lcolor)
 Set the line color.
 
virtual void SetLineColorAlpha (Color_t lcolor, Float_t lalpha)
 Set a transparent line color.
 
virtual void SetLineStyle (Style_t lstyle)
 Set the line style.
 
virtual void SetLineWidth (Width_t lwidth)
 Set the line width.
 
- Public Member Functions inherited from TAtt3D
 TAtt3D ()
 
virtual ~TAtt3D ()
 
virtual void Sizeof3D () const
 Set total size of this 3D object (used by X3D interface).
 

Protected Member Functions

Double_t FindClosestPhase (Double_t phi0, Double_t cosine)
 Finds the closest phase to phi0 that gives cos(phase) = cosine.
 
THelixoperator= (const THelix &)
 assignment operator
 
void SetRotMatrix ()
 Set the rotational matrix according to the helix axis.
 
- 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).
 
void MakeZombie ()
 

Protected Attributes

Double_t fAxis [3]
 
Double_t fPhi0
 
Double_t fRange [2]
 
TRotMatrixfRotMat
 
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.
 
Int_t fN
 Number of points.
 
TString fOption
 options
 
Float_tfP
 [3*fN] Array of 3-D coordinates (x,y,z)
 
- Protected Attributes inherited from TAttLine
Color_t fLineColor
 Line color.
 
Style_t fLineStyle
 Line style.
 
Width_t fLineWidth
 Line width.
 

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.
 
- Static Public Member Functions inherited from TObject
static Long_t GetDtorOnly ()
 Return destructor only flag.
 
static Bool_t GetObjectStat ()
 Get status of object stat flag.
 
static void SetDtorOnly (void *obj)
 Set destructor only flag.
 
static void SetObjectStat (Bool_t stat)
 Turn on/off tracking of objects in the TObjectTable.
 
- Protected Types inherited from TObject
enum  { kOnlyPrepStep = BIT(3) }
 

#include <THelix.h>

Inheritance diagram for THelix:
[legend]

Constructor & Destructor Documentation

◆ THelix() [1/4]

THelix::THelix ( )

Helix default constructor.

Definition at line 121 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 134 of file THelix.cxx.

◆ THelix() [3/4]

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

Helix normal constructor.

Definition at line 156 of file THelix.cxx.

◆ THelix() [4/4]

THelix::THelix ( const THelix helix)

Helix copy constructor.

Definition at line 235 of file THelix.cxx.

◆ ~THelix()

THelix::~THelix ( )
virtual

Helix destructor.

Definition at line 226 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 245 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 279 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 596 of file THelix.cxx.

◆ GetOption()

Option_t * THelix::GetOption ( ) const
inlinevirtual

Reimplemented from TObject.

Definition at line 57 of file THelix.h.

◆ operator=()

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

assignment operator

Definition at line 203 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 288 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 297 of file THelix.cxx.

◆ SetAxis() [1/2]

void THelix::SetAxis ( Double_t const *  axis)
virtual

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

Definition at line 321 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 346 of file THelix.cxx.

◆ SetHelix()

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

Set all helix parameters.

Definition at line 83 of file THelix.cxx.

◆ SetOption()

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

Reimplemented from TPolyLine3D.

Definition at line 60 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 356 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 549 of file THelix.cxx.

◆ SetRotMatrix()

void THelix::SetRotMatrix ( )
protected

Set the rotational matrix according to the helix axis.

Definition at line 567 of file THelix.cxx.

Member Data Documentation

◆ fAxis

Double_t THelix::fAxis[3]
protected

Definition at line 33 of file THelix.h.

◆ fgMinNSeg

Int_t THelix::fgMinNSeg =5
staticprotected

Definition at line 42 of file THelix.h.

◆ fPhi0

Double_t THelix::fPhi0
protected

Definition at line 30 of file THelix.h.

◆ fRange

Double_t THelix::fRange[2]
protected

Definition at line 35 of file THelix.h.

◆ fRotMat

TRotMatrix* THelix::fRotMat
protected

Definition at line 34 of file THelix.h.

◆ fVt

Double_t THelix::fVt
protected

Definition at line 29 of file THelix.h.

◆ fVz

Double_t THelix::fVz
protected

Definition at line 31 of file THelix.h.

◆ fW

Double_t THelix::fW
protected

Definition at line 32 of file THelix.h.

◆ fX0

Double_t THelix::fX0
protected

Definition at line 26 of file THelix.h.

◆ fY0

Double_t THelix::fY0
protected

Definition at line 27 of file THelix.h.

◆ fZ0

Double_t THelix::fZ0
protected

Definition at line 28 of file THelix.h.

Libraries for THelix:

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