feat: GX2F (experimental) + unit test

[AJPfleger]

A first implementation of the new Global Chi Square Fitter (GX2F). It is probably not performant and lacks many features but it is stable and testable. That's why it should live in the namespace Experimental.

[github-actions]

📊: Physics performance monitoring for fb5575a

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
• ✅ AMVF ttbar
• ✅ AMVF (+grid seeder) ttbar
• ✅ Truth tracking (GSF)
• ✅ Truth tracking
• ✅ Particles inital fatras
• ✅ Particles final fatras
• ✅ Particles inital geant4
• ✅ Particles final geant4

[codecov]

Codecov Report

Merging #2305 (fb5575a) into main (d8b6d67) will decrease coverage by 0.16%.
Report is 1 commits behind head on main.
The diff coverage is 33.60%.

@@            Coverage Diff             @@
##             main    #2305      +/-   ##
==========================================
- Coverage   49.70%   49.54%   -0.16%     
==========================================
  Files         452      453       +1     
  Lines       25468    25679     +211     
  Branches    11651    11811     +160     
==========================================
+ Hits        12658    12722      +64     
- Misses       4578     4583       +5     
- Partials     8232     8374     +142     

Files Changed	Coverage Δ
...clude/Acts/Vertexing/AdaptiveMultiVertexFinder.hpp	89.47% <ø> (ø)
...include/Acts/Vertexing/FullBilloirVertexFitter.ipp	27.97% <3.57%> (-5.64%)	⬇️
...nclude/Acts/Vertexing/KalmanVertexTrackUpdater.ipp	14.92% <13.88%> (-0.87%)	⬇️
...e/include/Acts/Vertexing/IterativeVertexFinder.ipp	27.20% <33.33%> (ø)
...nclude/Acts/TrackFitting/GlobalChiSquareFitter.hpp	39.26% <39.26%> (ø)
...clude/Acts/Vertexing/AdaptiveMultiVertexFinder.ipp	40.81% <50.00%> (+0.06%)	⬆️
...ore/include/Acts/Vertexing/KalmanVertexUpdater.ipp	28.57% <66.66%> (ø)
Core/include/Acts/Vertexing/TrackAtVertex.hpp	66.66% <66.66%> (-33.34%)	⬇️
...clude/Acts/Vertexing/AdaptiveMultiVertexFitter.ipp	44.73% <100.00%> (ø)

... and 1 file with indirect coverage changes

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[paulgessinger]

I'll draft this while it's still being worked on.

[benjaminhuth]

Looks good! :)
Some remarks about dead code etc.
You could make the std::couts to logging statements (I left a bunch of comments)...

[benjaminhuth]

Looks good from my side

[benjaminhuth]

Just updated the title so it doesn't get confused with the examples framework

Invalidated by push of 0ec11a6

[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

[paulgessinger]

Unrelated failure.