refactor: remove division of vertex covariance with weight

[felix-russo]

Removes the division of the vertex covariance matrix with a weight that depends on the annealing temperature.

I believe that the reasoning behind this practice is that the vertex covariance should decrease gradually with temperature. This seems however a bit random to me because

• the temperature is already considered in the track weights
• the chi2 corresponding to the weight is set to the arbitrary value 1
• there is no documentation on this that I know of. For example, https://link.springer.com/book/10.1007/978-3-030-65771-0 on page 154, the authors only mention the inflation of the track covariance matrices Vi, see
  

Let me know if I am missing something!

[codecov]

Codecov Report

Merging #2522 (aad0fc0) into main (ecc68bc) will increase coverage by 0.00%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #2522   +/-   ##
=======================================
  Coverage   49.76%   49.76%           
=======================================
  Files         466      466           
  Lines       26326    26323    -3     
  Branches    12097    12095    -2     
=======================================
- Hits        13101    13100    -1     
  Misses       4624     4624           
+ Partials     8601     8599    -2     

Files	Coverage Δ
...clude/Acts/Vertexing/AdaptiveMultiVertexFitter.ipp	44.07% <ø> (+0.20%)	⬆️

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[github-actions]

📊: Physics performance monitoring for aad0fc0

Full contents

physmon summary

• ✅ CKF truth_smeared
• ✅ IVF truth_smeared
• ✅ AMVF truth_smeared
• ✅ Track Summary CKF truth_smeared
• ✅ Seeding truth_estimated
• ✅ CKF truth_estimated
• ✅ IVF truth_estimated
• ✅ AMVF truth_estimated
• ✅ Track Summary CKF truth_estimated
• ✅ Seeding seeded
• ✅ CKF seeded
• ✅ IVF seeded
• ✅ AMVF seeded
• ✅ AMVF (+grid seeder) seeded
• ✅ Track Summary CKF seeded
• ✅ Seeding orthogonal
• ✅ CKF orthogonal
• ✅ IVF orthogonal
• ✅ AMVF orthogonal
• ✅ Track Summary CKF orthogonal
• ✅ Ambisolver seeded
• ✅ Ambisolver orthogonal
• ✅ Seeding ttbar
• ✅ CKF ttbar
• ✅ Ambisolver
• ✅ Track Summary CKF ttbar
• ✅ AMVF ttbar
• ✅ AMVF (+grid seeder) ttbar
• ✅ Truth tracking (GSF)
• ✅ Truth tracking
• ✅ Particles inital fatras
• ✅ Particles final fatras
• ✅ Particles inital geant4
• ✅ Particles final geant4

[paulgessinger]

Should we try to investigate where this comes from? @baschlag do you remember if this was discussed at some point?

[felix-russo]

I found the same line athena, might be helpful to for tracing where this comes from: https://gitlab.cern.ch/atlas/athena/-/blame/main/Tracking/TrkVertexFitter/TrkVertexFitters/src/AdaptiveMultiVertexFitter.cxx#L137

[baschlag]

Hi. This part was indeed just adopted from the original Athena implementation in order to guarantee numerical agreement between the ACTS and Athena version (which was needed for validating the code). So I think your changes look in fact very reasonable.

[paulgessinger]

Seems good to me then. Let's see what the CI says in terms of Athena outputs after we merge.

[acts-project-service]

🔴 Athena integration test results

🔴 Some tests have failed!

Please investigate the pipeline!

status	job
🟢	run_unit_tests
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsWorkflow.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateTracks.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateActsCoreSpacePoints.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateActsSpacePoints.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateSeeds.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateOrthogonalSeeds.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsValidateClusters.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsPersistifyEDM.sh
🟢	run_ci_tests: ../athena/AtlasTest/CITest/test/ActsKfRefitting.sh
🟢	run_ci_tests: python3 ../athena/Tracking/Acts/ActsGeometry/test/ActsExtrapolationAlgTest.py
🟢	run_ci_tests: python3 ../athena/Tracking/Acts/ActsGeometry/test/ActsITkTest.py
🟢	run_workflow_tests_run4_mc
🟢	run_workflow_tests_run2_mc
🔴	run_workflow_tests_run2_data
🔴	run_workflow_tests_run3_mc
🔴	run_workflow_tests_run3_data

[felix-russo]

Hm.. What should we do?

[paulgessinger]

If we want to tag another non-major version this week, we might have to revert this. That ok for you?

[felix-russo]

Sure, as long as it gets in at some point :)
I will prepare the PRs