acts: bug: interpolation out of bounds with ATLAS B-field map
Using the propagator with the ATLAS B-field map can give error messages:
TrackFinding ERROR Step failed with MagneticFieldError:1: Interpolation out of bounds was requested
This can give a lot of messages: ~259 MagneticFieldError
s per ttbar+μ=200 event, each of which produces 2 errors, and 4 warnings (1.6 GB logfile for 1000 events)!
This error is due to InterpolatedBFieldMap::getField()
called for a position outside the mapped ATLAS B-field
- The ATLAS B-field is mapped in (-10000,-10000,-15000) to (10000,10000,15000)
- but I see, calls for e.g.
getField({-2849, -2486, 54450})
- These are presumably for extension of seeds that will eventually be cut or rejected
#1467 removes these error messages by trying to return the edge-bin values instead of giving an error. That is still WiP because I couldn’t yet get it to pass the unit tests: seems to work with B=(0,0,0) at the edges (as for ATLAS), but not otherwise.
Even if that can be resolved, the question remains: why is getField()
called for points so far outside the detector? @Corentin-Allaire suggested (ACTS-ITk meeting) that the world volume is too large. If so, it may be an ATLAS-specific error, but I hope it’s OK to discuss here.
About this issue
- Original URL
- State: closed
- Created 2 years ago
- Comments: 22 (20 by maintainers)
Commits related to this issue
- fix: Fix CKF finalization (#2299) Apparently our CKF was not able to smooth multiple tracks for a single seed in some cases. The problem was that we expected the CKF actor to be called a second tim... — committed to acts-project/acts by andiwand a year ago
- fix: Fix CKF finalization (#2299) Apparently our CKF was not able to smooth multiple tracks for a single seed in some cases. The problem was that we expected the CKF actor to be called a second tim... — committed to paulgessinger/acts by andiwand a year ago
Looked into this today. The underlying bug looks quite significant to me and makes me wonder how the CKF produced any results at all…
Will create a fix and link it here.
https://github.com/acts-project/acts/pull/2299
I have removed the workaround for this issue from #1467 and confirmed that the errors still occur with the latest
main
(ITk ttbar+PU200):So back to square one. What next?