class AliVertexerTracks: public TObject

 Default constructor

 Standard constructor

 Default Destructor
 The objects pointed by the following pointer are not owned
 by this class and are not deleted

 Primary vertex for current ESD or AOD event
 (Two iterations:
  1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
      + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
  2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)

 Primary vertex using the AliExternalTrackParam's in the TObjArray.
 idOrig must contain the track IDs from AliESDtrack::GetID()
 (Two iterations:
  1st with 5*fNSigma*sigma cut w.r.t. to initial vertex
      + cut on sqrt(d0d0+z0z0) if fConstraint=kFALSE
  2nd with fNSigma*sigma cut w.r.t. to vertex found in 1st iteration)

 find vertex for events with 1 track, using DCA to nominal beam axis

 Get estimate of vertex position in (x,y) from tracks DCA

 Propagate tracks to initial vertex position and store them in a TObjArray

 COPIED from AliTracker

 Propagates the track to the plane X=xk (cm).

  Origin: Marian Ivanov,  Marian.Ivanov@cern.ch

 Removes tracks in trksTree from fit of inVtx

 Removes diamond constraint from fit of inVtx

  Cut values

  Cut values for ITS mode

  Cut values for TPC mode

 Mark the tracks not to be used in the vertex reconstruction.
 Tracks are identified by AliESDtrack::GetID()

 Set initial vertex knowledge

 Calculate the point at minimum distance to prepared tracks (TClonesArray)

 Calculate the point at minimum distance to prepared tracks (array of AliStrLine)

 Extract from the AliExternalTrackParam the global coordinates ri and covariance matrix
 wWi of the space point that it represents (to be used in VertexFitter())

 When the number of tracks is < fMinTracks,
 deal with vertices not found and prepare to exit

 The optimal estimate of the vertex position is given by a "weighted 
 average of tracks positions".
 Original method: V. Karimaki, CMS Note 97/0051

 Return vertex from tracks (AliExternalTrackParam) in array

 Return vertex from array of ESD tracks

 try to find a new vertex

 find and fit multiple vertices

 if multiple vertices are found, try to find the primary one and attach it as fCurrentVertex
 then attach pile-up vertices directly to esdEv

 clusterize tracks using z coordinates of intersection with beam axis
 and compute all vertices

 Configuration of multi-vertexing vis pre-clusterization of tracks