LArReco Calorimetry module places absolute cut on z position which is not detector independent
Christian Farnese is studying calorimetry with the ICARUS detector and reports the following problem:
... I am slowly proceeding on the studies I presented during the last Monday meeting related to dEdx evaluation...
in particular I am now trying to prepare a code that use the dE/dx measurement for the calibration of the detector: so I use a large number of cosmic muon tracks to evaluate channel by channel the dE/dx... but I discover something strange: the dE/dx was calculated only for the collection channel exceeding something like 2000... debugging in icaruscode I understand that there cut was not on the channel number but in the z coordinate... debugging outside icaruscode (installing in particular larreco) I discover that if you look to line 373 of the Calorimetry module in larreco
there is a cut on z at -100, that is clearly a problem for us (our z coordinate arrive to ~ -900)... it seems that removing that line, the problem I found is solved! You can find also just the result on 10 cosmic events: in blu the z coordinate of the 3D points with a dE/dx evaluated before removing the line I mentioned while in red you can see the additional points obtatined removing the line...
Indeed, if one looks at line 373 of the module one see:
if (xyz3d<-100) continue
The commit messaging implies this line appeared as something related to MIcroBooNE where z=0 is at the edge of the TPC, not the center. For ICARUS z=0 is in the center, this line essentially eliminates nearly half the active volume.
I'm assigning to Gianluca since I believe he has already a solution...
Make the cut on trajectory point position configurable.
In addition, make more extreme the value of some extreme constants that were not that extreme after all.
This solves LArSoft issue #23457.
#1 Updated by Tingjun Yang 8 months ago
I think I added that line when we first wrote the module for ArgoNeuT to ignore badly reconstructed points. Since most of the LArTPCs starts from z = 0, we have not had a problem with it yet.
I think the track reconstruction is mature enough that we don't need that check any more. If it causes problems for ICARUS, it should be removed.
#3 Updated by Gianluca Petrillo 8 months ago
- % Done changed from 0 to 90
- Status changed from New to Work in progress
- Co-Assignees Gianluca Petrillo added
A fix is pushed in larreco branch feature/gp_Issue23457 for testing.
The relevant commit is larreco:30baf419.
A new configuration parameter is introduced for
NotOnTrackZcut (default to
-100.0 for backward compatibility) excludes all points with z smaller that the parameter value.
Another change is the change of some "magic" invalid values from
std::numeric_limit<double>::lowest(): 1000 cm (10 m) is not so out of the world for ICARUS.
#6 Updated by Gianluca Petrillo 8 months ago
After having received approval by e-mail by Tingjun and Tracy, I am pushing a change to make this cut optional.
If can be restored in its past glory adding to the configuration of the module:
New commit is larreco:d189c4ca, still in larreco branch feature/gp_Issue23457.
This definitely makes it a breaking change.