Task #14281

Milestone #17338: Phase 3 Tracking Data Product

Provide an interface for access of reconstructed track information

Added by Gianluca Petrillo about 4 years ago. Updated about 3 years ago.

Target version:
Start date:
Due date:
% Done:


Estimated time:
100.00 h
Spent time:


Similarly as for clusters (issue #14265), add an interface providing access to track information:

  • providing access to all the pre-computed information currently available (currently recob::Track)
  • no less-than-trivial computation is performed
  • access to lower level associated objects; possibly incomplete list:
    • clusters (ideally via view::Cluster)
    • hits
    • vertices
    • trajectory points ("space points")
    • track seeds
  • access to truth information needs to be considered both in principle and in practice

This interface object, with the candidate name of view::Track, is bound to a main reconstruction action (that is, a track making module).
Careful consideration is needed as how to include vertex information: many tracking algorithms provide vertex information, but vertices can be as well produced by specific algorithms and then associated to tracks, or used as input to reconstruct tracks.
A simple approach is to stick to the same policy as for view::Cluster (issue #14265) and navigate only elements created with the main tracking module. Then, the other connections would be provided by a higher level abstraction (see issue #14061).

This task is related to the redefinition of the track data products, but it's not fully dependent on it since that one mainly deals with content and storage model, while this one mainly deals with access interface.

Related issues

Related to LArSoft - Necessary Maintenance #15453: Remove legacy data members from recob::TrackAssigned02/03/2017

Related to LArSoft - Necessary Maintenance #15446: BezierTrack should be removed from LArSoftClosed02/02/2017

Blocked by LArSoft - Feature #14786: Rediscuss the content of recob::TrackRejected12/08/2016

Associated revisions

Revision f75cbd73 (diff)
Added by Gianluca Petrillo almost 4 years ago

Changed deprecation warning to be less intrusive (see issue #14281 )


#1 Updated by Katherine Lato about 4 years ago

  • Status changed from New to Assigned

#2 Updated by Gianluca Petrillo about 4 years ago

  • Estimated time set to 60.00 h

This step is on hold until the new content of the tracking system is defined.

#3 Updated by Gianluca Petrillo about 4 years ago

  • Blocked by Feature #14786: Rediscuss the content of recob::Track added

#4 Updated by Gianluca Petrillo almost 4 years ago

The first step is the redefinition of the content of recob::Track.
The design and implementation of it is staged:

  1. the new data structures are plugged into LArSoft with an interface as backward-compatible as possible, to minimise the impact on current code
  2. the code is transitioned into the new interface; utilities are provided for writing the new objects in a compliant way and for basic navigation
  3. a complete navigation interface is provided

The delivery time of first stage is constrained by MicroBooNE production, whose official deadline is end of January 2017.

#5 Updated by Gianluca Petrillo almost 4 years ago

The material for stage 1 (see note 4) has been delivered in branches feature/cerati_TrackTrajectory (including lardataobj and others).

This is scheduled for merge into LArSoft v06_23_00 (which was basically delayed to merge it).

#6 Updated by Gianluca Petrillo almost 4 years ago

The new recob::Track class interface is as backward-compatible as possible to the old one.
Some data members are been left in there until there is agreement on how to life without them (issue #15453).

Interface change

Some data members underwent an interface change. These were the only cases where a change was unavoidable.

Return value changed from reference to value, because of internal changes:
  • DirectionAtPoint(), LocationAtPoint(), Vertex(), End(), VertexDirection(), EndDirection() return a TVector3 instead than a TVector3 const&
  • CovarianceAtPoint(), VertexCovariance() and EndCovariance() return a TMatrixD instead of a TMatrixD const&

Typically this is a problem when storing the return into a reference variable, e.g.

TVector const& vertex = track.Vertex();
The most durable, but less readable, way to fix this is to let the compiler do what it takes:
decltype(auto) vertex = track.Vertex();
will have vertex of whatever exact type recob::Track::Vertex() returns.
Be aware that this backward compatibility is going to be removed, and all these methods will return a recob::Track::Point_t or recob::Track::Vector_t as appropriate. Since these vectors have small differences in the interface with respect to TVector3, the following code (e.g., the one using vertex) may have to be fixed.
The same holds for the covariance matrices.

Deprecated methods

A few methods have been formally deprecated. This means that every time you use one of them in your code, the compiler will give you a warning.
You can and should fix your code to avoid that. Please also report cases where LArSoft still uses them, in case we missed (m)any.

  • Extent(std::vector<double>&, std::vector<double>&) const: use Extent() instead; it returns a pair of recob::Track::Point_t. If your use requires std::vector<double>, please contact us so that the downstream interface can be extended to support Point_t as well.
  • NumberFitMomentum(): the new protocol requires the presence of as many momenta as there are points in a track trajectory, or none at all. Therefore, use NumberTrajectoryPoints() to know how many of both there are in the track. Another use in the code was to determine whether there was momentum information available in the track or not. In that case, the usual check if (track.NumberFitMomentum() > 0) should be replaced by if (track.HasMomentum()).
Other data members and methods have been nominally deprecated:
  • TrajectoryAtPoint(size_t, TVector3&, TVector3&): the new method TrajectoryPoint(size_t) (no more At in the name!) returns a TrajectoryPoint_t object with copies of the direction and momentum. Note that this is different from before, where the returned vector was a direction rather than a momentum. Also, the results are not TVector3 any more, but rather Point_t and Vector_t.
  • Direction(double*, double*) has gone through a treatment similar to Extent(TVector3&, TVector3&) (see above); the return type of the replacement, Direction(), is a pair of Vector_t.
  • GlobalToLocalRotationAtPoint(size_t, TMatrixD&), LocalToGlobalRotationAtPoint(size_t, TMatrixD&) should be replaced by GlobalToLocalRotationAtPoint(size_t) and LocalToGlobalRotationAtPoint(size_t) respectively, which return a rotation matrix (Rotation_t) that can be used directly on Point_t and Vector_t objects.

These members have not formally deprecated yet, and the compiler will not issue any warning when used.

An example of dealing with the Extent() change and tips for upgrading TVector3 to GenVector vectors (used by the new recob::Track interface) can be found in the From ROOT vectors (TVector3) to ROOT GenVector wiki page.

#7 Updated by Gianluca Petrillo almost 4 years ago

#8 Updated by Lynn Garren almost 4 years ago

#9 Updated by Katherine Lato over 3 years ago

  • % Done changed from 0 to 60
  • Estimated time changed from 60.00 h to 100.00 h

#10 Updated by Katherine Lato over 3 years ago

as part of a discussion with Erica, Gianluca and Giuseppe, decided that to proceed on this will provide an interface for writing tracks and one for reading tracks that hides connections between tracks in other products.
Giuseppe will take care of the writing interface, Gianluca will take care of the reading interface.

#11 Updated by Katherine Lato over 3 years ago

  • Status changed from Assigned to Accepted
  • Assignee deleted (Gianluca Petrillo)
  • Parent task changed from #14060 to #17338

Moving this task to phase 3 of track work on data products.

#12 Updated by Katherine Lato about 3 years ago

  • Target version set to 2019-1-quarter

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