class AliExternalTrackParam: public AliVTrack

 default constructor

 copy constructor

 assignment operator

 create external track parameters from given arguments

 Recreate TrackParams from VTrack
 This is not a copy contructor !

 Constructor from virtual track,
 This is not a copy contructor !

 constructor from the global parameters

 create external track parameters from the global parameters
 x,y,z,px,py,pz and their 6x6 covariance matrix
 A.Dainese 10.10.08

 Resets all the parameters to 0

 Add "something" to the track covarince matrix.
 May be needed to account for unknown mis-calibration/mis-alignment

 This function returns the track momentum
 Results for (nearly) straight tracks are meaningless !

 This function returns the 1/(track momentum)

 This function calculates the transverse impact parameter
 with respect to a point with global coordinates (x,y)
 in the magnetic field "b" (kG)

 This function calculates the transverse impact parameter
 with respect to a point with global coordinates (xv,yv)
 neglecting the track curvature.

 This is the empirical ALEPH parameterization of the Bethe-Bloch formula.
 It is normalized to 1 at the minimum.

 bg - beta*gamma

 The default values for the kp* parameters are for ALICE TPC.
 The returned value is in MIP units

 This is the parameterization of the Bethe-Bloch formula inspired by Geant.

 bg  - beta*gamma
 kp0 - density [g/cm^3]
 kp1 - density effect first junction point
 kp2 - density effect second junction point
 kp3 - mean excitation energy [GeV]
 kp4 - mean Z/A

 The default values for the kp* parameters are for silicon.
 The returned value is in [GeV/(g/cm^2)].

 This is an approximation of the Bethe-Bloch formula,
 reasonable for solid materials.
 All the parameters are, in fact, for Si.
 The returned value is in [GeV/(g/cm^2)]

 This is an approximation of the Bethe-Bloch formula,
 reasonable for gas materials.
 All the parameters are, in fact, for Ne.
 The returned value is in [GeV/(g/cm^2)]

 Transform this track to the local coord. system rotated
 by angle "alpha" (rad) with respect to the global coord. system.

 rotate to new frame, ignore covariance

 Transform this track to the local coord. system rotated by 180 deg.

 Propagate this track to the plane X=xk (cm) in the field "b" (kG)

 Propagate this track to the plane X=xk (cm) in the field "b" (kG)
 Only parameters are propagated, not the matrix. To be used for small
 distances only (<mm, i.e. misalignment)

 Transform this track to the local coord. system rotated
 by angle "alpha" (rad) with respect to the global coord. system,
 and propagate this track to the plane X=xk (cm) in the field "b" (kG)

 Origin: K. Shileev (Kirill.Shileev@cern.ch)
 Extrapolate track along simple helix in magnetic field
 Arguments: len -distance alogn helix, [cm]
            bz  - mag field, [kGaus]
 Returns: x and p contain extrapolated positon and momentum
 The momentum returned for straight-line tracks is meaningless !

 Origin: K. Shileev (Kirill.Shileev@cern.ch)
 Finds point of intersection (if exists) of the helix with the plane.
 Stores result in fX and fP.
 Arguments: planePoint,planeNorm - the plane defined by any plane's point
 and vector, normal to the plane
 Returns: kTrue if helix intersects the plane, kFALSE otherwise.

 Estimate the chi2 of the space point "p" with the cov. matrix "cov"

 Returns the track residuals with the space point "p" having
 the covariance matrix "cov".
 If "updated" is kTRUE, the track parameters expected to be updated,
 otherwise they must be predicted.

 Update the track parameters with the space point "p" having
 the covariance matrix "cov"

 External track parameters -> helix parameters
 "b" - magnetic field (kG)

 Returns the (weighed !) distance of closest approach between
 this track and the track "p".
 Other returned values:
   xthis, xt - coordinates of tracks' reference planes at the DCA

 Propagate this track to the DCA to vertex "vtx",
 if the (rough) transverse impact parameter is not bigger then "maxd".
            Magnetic field is "b" (kG).

 a) The track gets extapolated to the DCA to the vertex.
 b) The impact parameters and their covariance matrix are calculated.

    In the case of success, the returned value is kTRUE
    (otherwise, it's kFALSE)

 Propagate this track to the DCA to vertex "vtx",
 if the (rough) transverse impact parameter is not bigger then "maxd".

 This function takes into account all three components of the magnetic
 field given by the b[3] arument (kG)

 a) The track gets extapolated to the DCA to the vertex.
 b) The impact parameters and their covariance matrix are calculated.

    In the case of success, the returned value is kTRUE
    (otherwise, it's kFALSE)

 This function returns a unit vector along the track direction
 in the global coordinate system.

 This function returns the global track momentum components
 Results for (nearly) straight tracks are meaningless !

 Returns x-component of momentum
 Result for (nearly) straight tracks is meaningless !

 Returns y-component of momentum
 Result for (nearly) straight tracks is meaningless !

 Returns x-component of first track point

 Returns y-component of first track point

 return theta angle of momentum

 Returns the azimuthal angle of momentum
 0 <= phi < 2*pi

 Returns the azimuthal angle of position
 0 <= phi < 2*pi

 return particle mass

 return particle energy

 return pseudorapidity

 return rapidity

 This function returns the global track position

 This function returns the global covariance matrix of the track params

 Cov(x,x) ... :   cv[0]
 Cov(y,x) ... :   cv[1]  cv[2]
 Cov(z,x) ... :   cv[3]  cv[4]  cv[5]
 Cov(px,x)... :   cv[6]  cv[7]  cv[8]  cv[9]
 Cov(py,x)... :   cv[10] cv[11] cv[12] cv[13] cv[14]
 Cov(pz,x)... :   cv[15] cv[16] cv[17] cv[18] cv[19] cv[20]

 Results for (nearly) straight tracks are meaningless !

 This function returns the global track momentum extrapolated to
 the radial position "x" (cm) in the magnetic field "b" (kG)

 This function returns the local Y-coordinate of the intersection
 point between this track and the reference plane "x" (cm).
 Magnetic field "b" (kG)

 This function returns the local Z-coordinate of the intersection
 point between this track and the reference plane "x" (cm).
 Magnetic field "b" (kG)

 This function returns the global track position extrapolated to
 the radial position "x" (cm) in the magnetic field "b" (kG)

 print the parameters and the covariance matrix

 Get sinus at given x

 Get the distance between two tracks at the local position x
 working in the local frame of this track.
 Origin :   Marian.Ivanov@cern.ch

 Draw track line

 Fill points in the polymarker

 *                                                                *
 *       GEANT3 tracking routine in a constant field oriented     *
 *       along axis 3                                             *
 *       Tracking is performed with a conventional                *
 *       helix step method                                        *
 *                                                                *
 *       Authors    R.Brun, M.Hansroul  *********                 *
 *       Rewritten  V.Perevoztchikov                              *
 *                                                                *
 *       Rewritten in C++ by I.Belikov                            *
 *                                                                *
 *  qfield (kG)       - particle charge times magnetic field      *
 *  step   (cm)       - step length along the helix               *
 *  vect[7](cm,GeV/c) - input/output x, y, z, px/p, py/p ,pz/p, p *
 *                                                                *

 Extrapolate this track to the plane X=xk in the field b[].

 X [cm] is in the "tracking coordinate system" of this track.
 b[]={Bx,By,Bz} [kG] is in the Global coordidate system.

 Extrapolate this track params (w/o cov matrix) to the plane X=xk in the field b[].

 X [cm] is in the "tracking coordinate system" of this track.
 b[]={Bx,By,Bz} [kG] is in the Global coordidate system.

Translation: in the event mixing, the tracks can be shifted
of the difference among primary vertices (vTrasl) and
the covariance matrix is changed accordingly
(covV = covariance of the primary vertex).
Origin: "Romita, Rossella" <R.Romita@gsi.de>

 Constrain TPC inner params constrained

 Get local X of the track position estimated at the radius lab radius r.
 The track curvature is accounted exactly

 The flag "dir" can be used to remove the ambiguity of which intersection to take (out of 2 possible)
 0  - take the intersection closest to the current track position
 >0 - go along the track (increasing fX)
 <0 - go backward (decreasing fX)

 This method has 3 modes of behaviour
 1) xyz[3] array is provided but alpSect pointer is 0: calculate the position of track intersection
    with circle of radius xr and fill it in xyz array
 2) alpSect pointer is provided: find alpha of the sector where the track reaches local coordinate xr
    Note that in this case xr is NOT the radius but the local coordinate.
    If the xyz array is provided, it will be filled by track lab coordinates at local X in this sector
 3) Neither alpSect nor xyz pointers are provided: just check if the track reaches radius xr

 Get track parameters at the radius of interest.
 Given function is aimed to be used to interactivelly (tree->Draw())
 access track properties at different radii

 TO BE USED WITH SPECICAL CARE -
     it is aimed to be used for rough calculation as constant field and
     no correction for material is used

 r  - radius of interest
 bz - magentic field
 retun values dependens on parType:
    parType = 0  -gx
    parType = 1  -gy
    parType = 2  -gz

    parType = 3  -pgx
    parType = 4  -pgy
    parType = 5  -pgz

    parType = 6  - r
    parType = 7  - global position phi
    parType = 8  - global direction phi
    parType = 9  - direction phi- positionphi

 Reset the covarince matrix to "something big"

  Sets the parameters, neglect cov matrix

 additional functions from AliVTrack

 Bethe-Bloch formula parameterizations

Deprecated

the calibration interface
--to be used in online calibration/QA
--should also be implemented in ESD so it works offline as well

protected: